Heterozygous Pathogenic Mutation Research Articles

P-39 A LATE ONSET CASE OF CHYLOMICRON RETENTION DISEASE

Abstract Introduction Chylomicron retention disease (CRD) is an uncommon genetic disorder caused by a mutation in the SAR1B gene, which encodes the Sar1b protein. Sar1b plays a role in transporting chylomicrons from the endoplasmic reticulum to the Golgi apparatus. Often diagnosed in the early stages of life, CRD typically presents with failure to thrive, gastrointestinal symptoms and malabsorption of fat, which leads to secondary clinical conditions such as hepatomegaly, neuromuscular disorders, hypolipidemia and deficiencies of fat soluble vitamins (A, D, E, K). Clinical Case A 56-year-old male patient was referred to our endocrinology outpatient clinic with low blood lipid levels. He expressed pain on his hands and feet. He also described vomiting after fat-rich meals since his childhood. He had no history of smoking or alcohol consumption. His father had diabetes mellitus and hypertension, and his uncle had coronary artery disease. His physical examination was normal besides a peripheral sensorial neuropathy. His laboratory findings showed hypolipidemia and hypochromic microcytic anemia, alongside with vitamin B12, vitamin D and iron deficiency (Table 1). An abdominal ultrasonography was performed, the dimensions of both the liver and the spleen was normal, though a grade 1 hepatosteatosis was observed. An electromyelography was performed and the findings were compatible with axonal polyneuropathy. The patient was referred to the department of genetics for evaluation of familial lipid disorders. A genetic analysis was performed, and the analysis revealed a likely pathogenic heterozygous mutation in the NM_016103.4 c.243dupA p.A82fs*35 area of the SAR1B gene. The patient was diagnosed with chylomicron retention disease. He was referred to a dietetician for a low-fat diet. A bone mineral density scan was planned and oral vitamin D treatment was initiated, alongside with oral iron and vitamin B12 treatment. The patient was also referred to departments of neurology, ophtalmology and cardiology for possible systemic involvement. He was also referred to gastroenterology for endoscopic and colonoscopic scanning. Moreover, his close relatives were advised to be evaluated for CRD. Later on, one of his grandchildren was diagnosed with CRD and is currently under treatment in another institution. Conclusion Though rarely diagnosed during adulthood, CRD should still be included in the differential diagnosis of patients with hypolipidemia; especially in cases with vitamin deficiencies. Gastrointestinal symptoms often encountered during childhood may be absent or vague in adulthood, but careful systemic assessment and physical examination gives valuable clues in the diagnosis of CRD, alongside with appropriate laboratory and genetic analysis. Once diagnosed, other family members, especially children, of CRD patients should also be evaluated about this rare genetic disease. Financial disclosures: None Funding resources: NoneTable 1:Laboratory findings of the patient

P-15 DIAGNOSTIC PITFALL - A RARE CASE OF HYPERCALCEMIA

Abstract Introduction Infantile hypercalcaemia type 1 (IIH) is an autosomal recessive disorder characterized by homozygous mutations in the CYP24A1 gene that encodes the 24-hydroxylase enzyme used to inactivate 1,25-(OH)2-vitamin D. Clinical Case A 24-year-old male was referred to our department for the evaluation of hypertension and nephrolithiasis, in the context of hypercalcemia. The general physical examination and the endocrinological assessment revealed no abnormalities. The patient was initially evaluated in nephrology & urology departments, where computed tomography (CT) revealed renal nephrocalcinosis and a lower right renal cyst, with no findings at thoracic level. Laboratory results confirmed hypercalcemia (total calcium 12.6 mg/dL, Ca++ at 5.49 mg/dL), alongside low parathyroid hormone (PTH) at 3 pg/mL. Malignancy was ruled out by normal PTH-related peptide levels (<0.5 pmol/L) and normal 25-hydroxyvitamin D levels (46 ng/mL), though 1,25-dihydroxyvitamin D was slightly elevated (81.8 pg/mL; Ref: 19.9−79.3 pg/mL). Bone metabolism markers, including FGF-23, serum crosslaps, and osteocalcin, were normal, excluding metabolic bone disease. Urine/24h: low urinary calcium (0.27 g/24h) and normal urinary phosphate (0.87 g/24h). In the diagnostic algorithm, hypercalcemia can be PTH-mediated, non-PTH-mediated, medication-induced, and miscellaneous causes. The patient's low PTH and suppressed PTH-rp excluded primary hyperparathyroidism and malignancy-related hypercalcemia. Normal 25(OH) vitamin D and slightly elevated 1,25(OH) vitamin D levels raised the suspicion of extrarenal 1-alpha-hydroxylation of vitamin D, a mechanism seen in granulomatous diseases such as sarcoidosis or tuberculosis, or in lymphomas. However, granulomatous diseases were excluded based on negative chest X-ray and thoracic CT findings and normal angiotensin-converting enzyme (ACE) levels. Other possible malignancies were excluded: germ cell tumors, such as non-seminomatous germ cell tumors, testicular cancers, particularly seminomas or choriocarcinomas, Hodgkin's lymphoma and multiple myeloma. Additionally, through medical history, clinical examination, and laboratory tests, we have also excluded hyperthyroidism, acromegaly, pheochromocytoma, adrenal insufficiency, bed rest/immobilization, parenteral nutrition, and supplements. Consequently, a genetic cause of abnormal renal calcium metabolism was suspected. Genetic testing revealed a heterozygous pathogenic mutation in the CYP24A1 gene, which is linked to Infantile Hypercalcemia Type 1. The patient's diagnosis of IIH was confirmed by the detection of the CYP24A1 mutation. Management of his condition focuses on controlling calcium levels through dietary intake and diuresis to prevent kidney stones, as there is no specific treatment available. Conclusion This case report highlights the importance of determining the etiology of hypercalcemia and the significance of genetic testing in clinical management.

The role of lysosomal acid lipase deficiency in dyslipidemia and liver disorders.

Cholesterol ester storage disease (CESD) is a rare autosomal recessive lysosomal storage disorder caused by mutations in the LIPA gene, leading to reduced lysosomal acid lipase activity, cholesterol ester accumulation, and systemic manifestations including liver dysfunction and dyslipidemia. We report the case of a 25-year-old male presenting with subacute jaundice, hyperbilirubinemia (total bilirubin 51 mg/dL, predominantly direct), and dyslipidemia characterized by elevated total cholesterol and low HDL cholesterol levels. Initial diagnostic workup for acute hepatitis and liver dysfunction, including serological and imaging studies, was unremarkable. Liver biopsy revealed canalicular cholestasis and T-lymphocyte infiltration without fibrosis, raising suspicion for a metabolic or genetic etiology. Genetic analysis confirmed a heterozygous pathogenic mutation (c.894 G>A) in the LIPA gene, establishing the diagnosis of CESD. The patient required advanced management with a molecular adsorbent recirculating system to address refractory hyperbilirubinemia. CESD often mimics other metabolic and hepatic conditions, such as familial hypercholesterolemia or non-alcoholic fatty liver disease, necessitating high clinical suspicion and genetic confirmation for diagnosis. This case underscores the importance of recognizing CESD in patients with atypical dyslipidemia and persistent hepatic abnormalities, as early identification enables targeted therapeutic interventions, including Sebelipase alfa enzyme replacement therapy.

The effect of gene dosage and age at the disease onset on the severity of familial Mediterranean fever

ABSTRACT Objective To compare the demographic and clinical characteristics of familial Mediterranean fever (FMF) patients according to age at disease onset and evaluate the dose effect of the number of pathogenic or likely pathogenic exon 10 mutations of the MEFV gene on disease severity. Methods This medical record review study was performed on 485 pediatric FMF patients with uni- or bialelic exon 10 mutations of the MEFV gene (M694V, M694I, M680I, V726A, R761H, T267I). Patients were grouped according to age at disease onset (Group 1:<6 years; Group 2:6–11 years; and Group 3:>11 years). Disease severity was assessed by the international severity scoring system for FMF (ISSF). Results Of the patients, 294 (60.6%) were classified in Group 1, 152 (31.4%) in Group 2 and 39 (8%) in Group 3. The mean elapsed time to diagnosis was 26.7 ± 27.4 months in Group 1 and was higher than the other groups (p < 0.001). During the attack, fever was higher in Group 1, arthritis in Group 2, and chest pain in Group 3 (p < 0.001). The median ISSF score was similar in patients with uni- or bialelic mutations in Group 1 and 3 (p = 0.086, p = 0.35, respectively) but lower in heterozygous patients in Group 2 (p < 0.001). In Groups 1 and 2, mild disease severity was higher in heterozygotes, while moderate disease severity was higher in homozygotes (p = 0.034, p = 0.001, respectively). Conclusion The presence of pathogenic or likely pathogenic homozygous or compound heterozygous mutations in exon 10 of the MEFV gene in patients with early-onset disease is associated with a more severe disease course compared to patients with heterozygous mutations. The gene dose effect of the number of mutations on disease severity is more common in children aged 6-11 years.

De novo SCN1A missense variant in a patient with Parkinson's disease.

Variants in a gene encoding sodium voltage-gated channel alpha subunit 1 (SCN1A) are known to cause a broad clinical spectrum of epilepsy and associated features, including Dravet syndrome (MIM 607208), non-Dravet developmental and epileptic encephalopathy (MIM 619317), familial febrile seizures (MIM 604403), familial hemiplegic migraine (MIM 609634), and generalized epilepsy with febrile seizures (MIM 604403). In this study, we examined a patient with Parkinson's disease (PD) without any clinical manifestations of epilepsy and associated features. Genomic nucleic acid was extracted, and a complete coding sequence of the human genome (whole-exome sequencing) was sequenced. Moreover, Sanger sequencing of variants of interest was performed to validate the exome-discovered variants. We identified a heterozygous pathogenic missense mutation (c.1498C>T; p.Arg500Trp) in the SCN1A gene in the patient using the whole-exome sequencing approach. The onset of PD features in our patient occurred at the age of 30 years. Biochemical investigations were carried out to rule out any secondary cause of the disease, including Wilson's disease or another metabolic disorder. MRI of the brain and spinal images were unremarkable. Moreover, a dramatic response to carbidopa-levodopa treatment was also observed in the patient. Our results suggest that the pathogenic variant in SCN1A may lead to PD features without epilepsy.

Cryo-EM structure of the human native plasma coagulation factor XIII complex

AbstractThe structure of human coagulation factor XIII (FXIII), a heterotetrameric plasma protransglutaminase that covalently cross-links preformed fibrin polymers, remains elusive until today. The heterotetrameric complex is composed of 2 catalytic FXIII-A and 2 protective FXIII-B subunits. Structural etiology underlying FXIII deficiency has so far been derived from crystallographic structures, all of which are currently available for the FXIII-A2 homodimer only. Here, we present the cryogenic electron microscopy structure of a native, human plasma–derived FXIII-A2B2 complex at 2.4 Å resolution. The structure provides detailed information on FXIII subunit interacting interfaces as the 2 subunits interact strongly in plasma. The native FXIII-A2B2 complex reveals a pseudosymmetric heterotetramer of 2 FXIII-B monomers intercalating with a symmetric FXIII-A2 dimer forming a “crown”-like assembly. The symmetry axes of the A2 and B2 homodimers are twisted relative to each other such that Sushi domain 1 interacts with the catalytic core of the A subunit, and Sushi domain 2 with the symmetry related A′ subunit, and vice versa. We also report 4 novel mutations in the F13A1 gene encoding the FXIII-A subunit from a cohort of patients with severe FXIII deficiency. Our structure reveals the etiological basis of homozygous and heterozygous pathogenic mutations and explains the conditional dominant negative effects of heterozygous mutations. This atomistic description of complex interfaces is consistent with previous biochemical data and shows a congruence between the structural biochemistry of the FXIII complex and the clinical features of FXIII deficiency.

Nodule-specific NRF2-targeted upregulation in patients with KEAP1 mutations and familial nontoxic multinodular goiter.

Kelch-like ECH-associated protein 1 (KEAP1) is associated with nuclear factor erythroid-2 related factor 2 (NRF2) and promotes NRF2 degradation in normal conditions. Genetic abnormality in KEAP1 is a rare disease and presents with familial multinodular goiter. This study assessed the clinical and molecular findings concerning nodular formation in the thyroid gland of patients harboring KEAP1 germline mutations. Next-generation sequencing analysis targeting goiter-associated genes was performed on 39 patients with familial multinodular goiter. The expression of NRF2-targeted genes from surgical thyroid specimens of patients with KEAP1 mutations were analyzed using a whole transcript expression array and immunohistochemistry. We found five probands with pathogenic heterozygous mutations in KEAP1 (p.Q86*, p.L136P, p.V411fs, p.R415C, and p.R483H), which had no meaningful concomitance with mutations of other goiter-associated genes in germline and somatic levels. Their common histopathological features showed multinodular goiters in the entire thyroid gland with few degenerative lesions or complications of malignancy and slow proliferation indicating < 1% at the Ki-67 labeling index. Among 42 NRF2-targeted genes, antioxidant genes were most frequently upregulated (11/12) in the nodule, followed by detoxification genes (6/11). Immunohistochemical analysis showed relatively high expression of glutathione peroxidase 2 and NAD(P)H quinone oxidoreductase 1 (representative NRF2-targeted genes) in the nodules of various patients harboring KEAP1 mutations. KEAP1 germline heterozygous mutations exert excessive NRF2 activity in the thyroid gland and may confer cytoprotective effects even under abundant reactive oxygen species associated with thyroid hormone production, resulting in thyroid hyperplasia with scarce degradation.

6989 Novel Use of Dual GIP/GLP-1 Receptor Agonist in HNF4A-MODY

Abstract Disclosure: A. Mehdi: None. M.C. Foss de Freitas: Advisory Board Member; Self; PTC Pharmaceuticals. Other; Self; Scientific presenter in a symposium funded by Amryt Pharmaceuticals. C.L. Martin: None. B.E. Gregg: None. N. Nachawi: None. E. Frontera: None. E.A. Oral: Consulting Fee; Self; Amryt Pharmaceuticals, Akcea Therapeutics, Ionis Pharmaceuticals Inc., Regeneron Pharmaceuticals. Grant Recipient; Self; Amryt Pharmaceuticals (now part of Cheisi, manufacturer of metreleptin), Akcea Therapeutics, Ionis Pharmaceuticals Inc., Regeneron Pharmaceuticals, Novo Nordisk, Rhythm Pharmaceuticals, Fractyl Laboratories, GI Dynamics (now Morfic Medical. Other; Self; Royalty rights from the use of Metreleptin in lipodystrophy. W.H. Herman: Advisory Board Member; Self; Member of the Data Safety and Monitoring Board for Merck Sharp &amp; Dohme, LLC, Memer of the Data Safety and Monitoring Board for Rivus Pharmaceuticals. Other; Self; Chair for the National Committee for Quality Assurance (NCQA) Healthcare Effectiveness Data and Information Set (HEDIS) Workgroup. D.T. Broome: Consulting Fee; Self; Tayco, Inc. Research Investigator; Self; Novo Nordisk, Fractyl Laboratories, Rhythm Pharmaceuticals, Inc. HNF4A-MODY (formerly MODY-1) is an autosomal dominant form of diabetes caused by a mutation in the transcription factor HNF4A[1],2. Affected patients are initially very sensitive to the anti-hyperglycemic effect of sulfonylureas, but become unresponsive to sulfonylureas at a rate of 1-4% per year3. Recently, the efficacy of glucagon-like peptide-1 receptor agonists has been demonstrated in HNF4A-MODY2, but there have been no reports on the use of dual gastric inhibitory polypeptide/glucagon-like peptide-1 receptor agonists (dual GIP/GLP-1 RA) in HNF4A-MODY. This report describes a patient with HNF4A-MODY who was treated with a dual GIP/GLP-1 RA. A 42-year-old White male with a pathogenic heterozygous mutation in Q268X was diagnosed with HNF4A-MODY at the age of 10 years (part of the RW pedigree)3. He was diagnosed with diabetes at age 20, treated with metformin from age 20 to age 30, and had glipizide extended release added at age 30. His dose of glipizide was titrated over 9-years to the maximum therapeutic dose. At the age of 40, when his HbA1c was no longer controlled, dulaglutide 1.5 mg once weekly was added. Thereafter, his HbA1c was well controlled between 5.5-7.0%, until it increased to 7.7%. He was then transitioned from dulaglutide to tirzepatide 5 mg once weekly for 4 weeks, 7.5 mg once weekly for 4 weeks, then 10 mg once weekly. He has been maintained on tirzepatide 10 mg once weekly, glipizide extended release 10 mg once daily, and metformin 1,000 mg twice daily without significant side effects. His HbA1c improved from 7.7% to 5.8% and he lost 7 lbs since transitioning from dulaglutide to tirzepatide (while on tirzepatide for 4 months in total). During his recent visit, he was without significant hyper- or hypoglycemia and his BMI was 31.2 kg/m2. (down from 32.32 kg/m2). To our knowledge, this is the first case report demonstrating preliminary efficacy of dual GIP/GLP-1 receptor agonist in HNF4A-MODY. While it is known that GIP and GLP-1 can cause glucose stimulated insulin secretion, and the mechanism of GLP-1 was previously described in MODY4, the differential effects and/or predominance of GIP or GLP-1 in MODY requires further investigation.

6415 Resistance to Thyroid Hormone -A Challenge to Manage

Abstract Disclosure: A. Altaf: None. F. Iqbal: None. E. Hamoudeh: None. C. Coyne: None. K. Anne: None. L. Buckley: None. Background: Resistance to thyroid hormone (RTH) or Refetoff syndrome was first introduced in 1967. It is an autosomal dominant or recessive genetic disease with a mutation in the thyroid hormone receptorβ (THR-β) gene or the thyroid hormone receptorα (THR-α) gene. The distinguishing biochemical feature of RTHβ is an elevated level of circulating free thyroid hormones with normal or high TSH concentration and decreased peripheral tissue response to thyroid hormone. Common signs and symptoms in patients with RTHβ are short stature, attention deficit disorder, and resting tachycardia and many patients might be asymptomatic. Case: We report a case of a 36-year-old patient with past medical history of congenital bilateral hearing loss, atrial fibrillation, CHF, and slow learning/comprehending who presented to the ER with shortness of breath and atrial fibrillation with tachycardia. Admission labs revealed elevated TSH 3.9, elevated fT4 3.28, and elevated TT3 205. He reported that for the past year, he has been on levothyroxine 50mcg for abnormal TSH. Levothyroxine was stopped and the patient was discharged on methimazole 10mg daily. Further workup revealed negative thyroglobulin and thyroid peroxidase antibodies. Thyroid ultrasound with Doppler demonstrated a mildly hypervascular thyroid gland without evidence of nodules. Brain MRI was negative for any pituitary abnormalities. HAMA testing continued to show elevated TSH. Patient was followed by cardiology and due to continued atrial fibrillation, had multiple cardioversions and was managed on a beta blocker. Due to his atrial fibrillation, endocrinology service continued his methimazole till his genetic testing came positive for an autosomal dominant heterozygous pathogenic mutation in THRB c.1373 T&amp;gt;C (p. Val458Ala). His thyroid hormones and TSH continue to be elevated. Currently, he is not on thyroid medication and getting monitored. The need for multiple cardioversions for atrial fibrillation in this patient makes resistance to thyroid hormone management challenging. Discussion: Hyperthyroidism is commonly mistaken for RTH. However, the lack of TSH suppression should be further investigated. Most patients with RTHβ are adequately compensated by the increased endogenous supply of thyroid hormone showing increased serum fT3 and fT4 levels and normal or near normal TSH levels. Beta Blockers like atenolol cannot inhibit the conversion of T4 to T3 and can be used for RTHβ with tachycardia. Triiodothyroaceticacid (TRIAC) or dextrothyroxine (DT4) have also been used to treat thyrotoxicosis. In summary, treatment for RTHβ remains a challenge for clinicians, especially in patients with atrial fibrillation and many patients are misdiagnosed and managed as hyperthyroidism. Presentation: 6/3/2024

Expanding the spectrum of progressive familial intrahepatic cholestasis: A report of 3 cases.

Progressive familial intrahepatic cholestasis (PFIC) is a group of autosomal recessive disorders caused by defects in bile secretion or transport usually presenting as cholestasis in pediatric age. Herewith, we describe 3 PFIC cases with diagnostic challenges and highlight the role of genetic analysis. The clinical history, laboratory data, liver biopsy, and molecular analysis for each case were reviewed. Case 1, a Hispanic male from Puerto Rico with hepatomegaly since age 2 months, was eventually diagnosed with PFIC3 following identification of a homozygous splice site variant in ATP binding cassette subfamily B member 4 (ABCB4) (c.2784-12T>C) at age 17 years by whole-exome sequencing (WES). Case 2 was a 37-year-old man with a history of alcoholism, abnormal liver function tests, and ductopenia on biopsy. Molecular testing revealed a pathogenic heterozygous ABCB4 mutation (c.1633C>T) variant leading to a diagnosis of PFIC3. Case 3 was a 2-year-old female initially presenting as a drug-induced liver injury but was diagnosed with PFIC10 following identification of a heterozygous frameshift mutation (p.Asp300Trpfs*19) and a heterozygous missense mutation (c.1357T>C) in myosin VB (MYO5B) by WES. These PFIC cases highlight the heterogenous presentation and diagnostic challenges, and they emphasize the role of next-generation sequencing, particularly the utility of WES.

Carrying both the heterozygous Myh6-R453C and Tnnt2-R92W mutations aggravate the hypertrophic cardiomyopathy phenotype in mice

Hypertrophic cardiomyopathy (HCM) is an inherited disease of the heart muscle that is dominated by variations in eight genes encoding sarcomere proteins. Although there are clinical or basic research reports that carrying double mutations can lead to more severe HCM phenotypes, there are also research reports that after reanalyzing the reported mutations, the severity of clinical symptoms in patients with double mutations did not significantly increase compared to patients with only one mutation. To determine whether double pathogenic mutations can aggravate the phenotype of hypertrophic cardiomyopathy in mice, we constructed mice carrying single pathogenic heterozygous mutation Myh6-R453C or Tnnt2-R92W and mice carrying both pathogenic heterozygous mutations. Our results showed that mice with double heterozygous mutations exhibited significant hypertrophic cardiomyopathy phenotypes at 4 weeks of age, and the degree of hypertrophy was significantly higher than that of single heterozygous mutant mice of the same age. Our study suggests that carrying the two pathogenic heterozygous mutations simultaneously can aggravate the phenotype of HCM in mice, which provides experimental evidence for the genotype-phenotype relationship of double pathogenic mutations and provides reference significance for clinical risk stratification of HCM patients.

Heterozygous variants in transmembrane channel-like 1 gene cause autosomal recessive nonsyndromic hearing loss.

Autosomal recessive non-syndromic hearing loss (ARNSHL) can cause severe or very severe pre-speech hearing loss. Transmembrane channel-like 1 (TMC1) gene is the sixth deafness gene discovered, but the precise extent of its protein structure and function is unknown. First, history collection, audiology examination and imaging examination were performed on the proband and his family members. Peripheral blood of proband and family members was collected, genomic DNA was extracted, exon high-throughput sequencing technology was used to detect the deafness gene mutation of the proband, and Sanger sequencing was performed to verify the TMC1 gene of the proband's parents. The proband was born with hearing impairment, normal tympanic function, inability to induce acoustic reflex in both ears (acoustic reflex threshold is 100 dBHL), and severe sensorineural deafness. One of his sisters has severe sensorineural hearing loss, and neither his parents nor his other sister is hearing impaired. High-throughput sequencing of the proband identified mutations at c.741+3_741+6delAAGT (splicing) and c.884C>T (p.A295V) of the TMC1 gene, two of which were heterozygous mutations. Sanger sequencing confirmed that the c.884C > T mutation was inherited from the mother, while the c.741+3_741+6delAAGT mutation was derived from the father. Prediction of amino acid function suggested that both mutations were pathogenic mutations. In conclusion, we found a new pathogenic complex heterozygous mutation of the TMC1 gene, which enriched the mutation spectrum of the TMC1 gene and provided a basis for genetic counseling and prenatal diagnosis of ARNSHL.

Differentiating non-epileptic seizures from epileptic seizures in Glut1 deficiency syndrome.

To investigate the clinical characteristics of non-epileptic seizures due to transient brain dysfunction caused by energy deficiency after prolonged fasting or exercise in individuals with glucose transporter type 1 deficiency syndrome (Glut1DS), and then elucidate further the seizure features to distinguish non-epileptic seizures from epileptic seizures. This retrospective case-control study included 57 non-epileptic seizures and 23 epileptic seizures (control group) in 14 individuals (11 males, three females; aged 5-44 years, median = 20 years) with Glut1DS, all with a heterozygous pathogenic SLC2A1 mutation. Non-epileptic seizures were classified as paroxysmal altered consciousness (n = 8), movement disorders (n = 35) (eye-head movements, ataxia, spasticity, weakness, involuntary movement), dysaesthesia (n = 8), and vomiting (n = 6) at the peak ages at onset of 5 to 10 years. Ketogenic diet therapy was effective in 33 of 43 (77%) non-epileptic seizures. Providing supplementary food before high-impact exercise or during attacks prevented or mitigated non-epileptic seizures in some individuals. Glut1DS-associated non-epileptic seizures are fundamentally situation-related seizures with specific provoking and ameliorating factors. Non-epileptic seizures can be distinguished from epileptic seizures by the absence of complete consciousness loss and rapid postictal recovery despite prolonged seizures. Non-epileptic seizures are not well recognized but require different therapeutic approaches compared to epileptic seizures. Awareness of the differentiation of non-epileptic seizures from epileptic seizures is essential when performing preventive or therapeutic decision-making for acute exacerbation seizures. Non-epileptic seizures are invariably situation-related seizures. Non-epileptic seizures were classified as altered consciousness, movement disorders, dysaesthesia, and vomiting. Non-epileptic seizures were characterized by the absence of complete consciousness loss and were accompanied by rapid recovery. Non-epileptic seizures can occur simultaneously or consecutively with another. Supplementary food can be effective in preventing the development of sustained exercise-induced movement disorders.

Acute heart failure in a neonate

The male patient, one day old, was admitted to the hospital due to hypoglycemia accompanied by apnea appearing six hours after birth. The patient had transient hypoglycemia early after birth, and acute heart failure suddenly occurred on the eighth day after birth. Laboratory tests showed significantly reduced levels of adrenocorticotropic hormone and cortisol, and pituitary magnetic resonance imaging was normal. Genetic testing results showed that the patient had probably pathogenic compound heterozygous mutations of the TBX19 gene (c.917-2A>G+c.608C>T), inherited respectively from the parents. The patient was conclusively diagnosed with congenital isolated adrenocorticotropic hormone deficiency caused by mutation of the TBX19 gene. Upon initiating hydrocortisone replacement therapy, cardiac function rapidly returned to normal. After being discharged, the patient continued with the hydrocortisone replacement therapy. By the 18-month follow-up, the patient was growing and developing well. In neonates, unexplained acute heart failure requires caution for possible endocrine hereditary metabolic diseases, and timely cortisol testing and genetic testing should be conducted.

Resistance to thyroid hormone and nonfunctioning pituitary microadenoma in a 13-year-old boy with THRB mutation.

Resistance to thyroid hormone (RTH) is a rare syndrome characterized by elevated serum free iodothyronines levels and non-suppressed thyroid stimulating hormones (TSH). The most common cause of RTH is heterozygous pathogenic mutations in thyroid hormone receptor β gene (THRB). Because of the similarities in biochemical profiles, differential diagnosis between RTHβ and TSH-secreting pituitary adenoma (TSHoma) is important, and accurate RTHβ diagnosis is essential to prevent inappropriate treatment. A 13-year-old boy was referred to our hospital for a microadenoma and uncontrolled hyperthyroidism despite use of methimazole for more than one year. He suffered from thyrotoxic clinical features and elevated serum T3 and fT4, and normal ranges for TSH and other pituitary hormones were noted. TSH receptor antibody was undetectable, and pituitary MRI revealed a 3mm-sized microadenoma. A TRH stimulation test showed normal TSH response, and the TSH-α-subunit level was not elevated, which is consistent with RTH. The patient was diagnosed with RTHβ and coexistent non-functioning pituitary microadenoma based on identification of a heterozygous mutation, c.1021C>G (p.Leu341Val), in THRB. Methimazole treatment was stopped, and a β-adrenergic blocking agent was started, subsequently thyrotoxic symptoms were relieved. Currently, only one pediatric case diagnosed with RTH and TSHoma has been reported so far, and this case is the first to report a pediatric case of coexistence of RTH and non-functioning pituitary microadenoma. Also, this case shows that inappropriate secretion of thyroid hormones requires careful clinical diagnosis to avoid unnecessary and potentially harmful management.

Skewed X-chromosome inactivation drives the proportion of DNAAF6-defective airway motile cilia and variable expressivity in primary ciliary dyskinesia

BackgroundPrimary ciliary dyskinesia (PCD) is a rare airway disorder caused by defective motile cilia. Only male patients have been reported with pathogenic mutations in X-linked DNAAF6, which result in the...

A Pilot Study on BRCA1/2 and PI3K Mutations Across Subtypes of Triple Negative Breast Cancer in North Indian Population.

BRCA1/2 are tumor suppressor genes which regulate the DNA repair mechanism. Mutations in BRCA1/2 may increase the risk of breast cancer in patients. In the present study frequency of BRCA1/2 mutations in triple negative breast cancer (TNBC) patients was assessed and correlated with molecular subtypes of TNBC. Blood samples from 65 confirmed cases of TNBC were collected. DNA was isolated from whole blood and libraries were prepared using a BRCA1/2 custom panel. Sequencing was done on Ion torrent S5 sequencer and ion reporter was used for data analysis. Further molecular subtyping of mutation positive TNBC cases was done using immunohistochemistry markers CK5/6; CK4/14; Vimentin and E-Cadherin and androgen receptor (AR) using tissue microarray. Twenty five of 65 patients had heterozygous pathogenic mutations, alterations with conflicting interpretation of pathogenicity, variants of uncertain significance and variants of unknown significance. Nine patients had pathogenic mutation in BRCA 1 gene only and 2 patients had pathogenic mutations in BRCA2 gene. Two patients were transheterozygous for BRCA mutations, that is, had pathogenic mutations in both BRCA1/2 genes simultaneously and 5 were compound heterozygous (involving BRCA2 gene in all the cases). Prevalent subtypes among BRCA positive cases were unclassified subtype (n=4, 33%), Basal like (n=5, 41%), and mesenchymal subtype (n=3, 25%). None of the LAR subtype showed BRCA1/2 mutations. The present study observed that the BRCA1 mutation is more frequent than BRCA2 mutation in TNBC. BRCA1/2 mutations do not correspond to BRCAness or basal phenotype. Considering high incidence of breast cancer and lack of correlation of basal morphology with BRCA1/2 mutation, the molecular methods should be used for screening for BRCA1/2 mutations. This will not only help in familial screening but also in deciding targeted therapy with PARP (poly-ADP ribose polymerase) inhibitors.

Highly efficient CRISPR/Cas9-mediated exon skipping for recessive dystrophic epidermolysis bullosa.

Gene therapy based on the CRISPR/Cas9 system has emerged as a promising strategy for treating the monogenic fragile skin disorder recessive dystrophic epidermolysis bullosa (RDEB). With this approach problematic wounds could be grafted with gene edited, patient-specificskin equivalents. Precise gene editing using homology-directed repair (HDR) is the ultimate goal, however low efficiencies have hindered progress. Reframing strategies based on highly efficient non-homologous end joining (NHEJ) repair aimed at excising dispensable, mutation-harboring exons offer a promising alternative approach for restoring the COL7A1 open reading frame. To this end, we employed an exon skipping strategy using dual single guide RNA (sgRNA)/Cas9 ribonucleoproteins (RNPs) targeted at three novel COL7A1 exons (31, 68, and 109) containing pathogenic heterozygous mutations, and achieved exon deletion rates of up to 95%. Deletion of exon 31 in both primary human RDEB keratinocytes and fibroblasts resulted in the restoration of type VII collagen (C7), leading to increased cellular adhesion in vitro and accurate C7 deposition at the dermal-epidermal junction in a 3D skin model. Taken together, we extend the list of COL7A1 exons amenable to therapeutic deletion. As an incidental finding, we find that long-read Nanopore sequencing detected large on-target structural variants comprised of deletions up to >5 kb at a frequency of ~10%. Although this frequency may be acceptable given the high rates of intended editing outcomes, our data demonstrate that standard short-read sequencing may underestimate the full range of unexpected Cas9-mediated editing events.

P33 A lichenoid eruption and severe eczema in association with IMAGe syndrome

Abstract IMAGe syndrome is a rare genetic disorder. IMAGe is an acronym for; (1)Intrauterine restricted growthMetaphyseal dysplasiaCongenital adrenal hypoplasiaGenitourinary abnormalities in males (cryptorchidism, micropenis, and hypospadias) Diagnosis is established by molecular genetic testing with heterozygous CDKN1C pathogenic mutation or a proband with suggestive findings in the PCNA (proliferating cell nuclear antigen)- binding domain of the maternally expressed allele. Additional features include characteristic facies (frontal bossing), developmental delay, immunodeficiency, osteoporosis and scoliosis. Severe, early onset eczema has been described in association with this syndrome. (2) We present the case of a 15-year-old boy with proven IMAGe syndrome, longstanding history of atopic dermatitis, and new onset lichenoid eruption on the forearms.

A Single nucleotide polymorphism in the ALDH2 gene modifies the risk of esophageal squamous cell carcinoma in BRCA2 p.K3326* carriers.

Esophageal squamous cell carcinoma (ESCC) has a very high incidence rate in northeastern Iran. Our team previously reported the BReast CAncer gene 2 (BRCA2) p.K3326* mutation as a moderately penetrant ESCC susceptibility variant in northern Iran (odds ratio (OR) = 3.64, 95% confidence interval (CI) = 1.74-7.59, P = 0.0003). Recently, it has been reported that aldehydes can induce BRCA2 haploinsufficiency in cells with a heterozygous pathogenic BRCA2 mutation and predispose them to carcinogenic effects. Based on this observation, we speculate that dysfunctional variants in Aldehyde Dehydrogenase 2 Family Member (ALDH2) may result in aldehyde-induced BRCA2 haploinsufficiency and increase cancer risk in BRCA2 mutation carriers. In support of this hypothesis, our team recently reported the breast cancer risk modifying effect of an ALDH2 common polymorphism, rs10744777, among Polish carriers of the BRCA2 p.K3326* mutation. In the current case-control study, we aimed to investigate the ESCC risk modifying effect of this ALDH2 polymorphism among BRCA2 p.K3326* mutation carriers. We assessed the interaction between the ALDH2 rs10744777 polymorphism and BRCA2 p.K3326* mutation in ESCC risk by genotyping this ALDH2 variant in the germline DNA of 746 ESCC cases and 1,373 controls from northern Iran who were previously genotyped for the BRCA2 p.K3326* mutation. Among a total of 464 individuals with TT genotype of the ALDH2 rs10744777 polymorphism, which is associated with lower ALDH2 expression, we found 9 of 164 cases versus 3 of 300 controls who carried the BRCA2 p.K3326* variant (OR = 5.66, 95% CI = 1.22-26.2, P = 0.018). This finding supports our hypothesis that the ALDH2-rs10744777 TT genotype may be a significant risk modifier of ESCC in individuals with a BRCA2 p.K3326* mutation.