Rare Presentation of Homozygous SLC20A2 Mutations Causing Intra‐Arterial Cerebral Vasculopathy and Stroke in Infancy: Case Report and Review of the Literature

Known hereditary human diseases featuring impaired copper trafficking across cellular membranes involve ATP7A (Menkes disease, occipital horn disease, X-linked spinal muscular atrophy type 3) and ATP7B (Wilson disease). Herein, we report a newborn infant of consanguineous parents with a homozygous pathogenic variant in a highly conserved sequence of SLC31A1, coding for the copper influx transporter 1, CTR1. This missense variant, c.236T > C, was detected by whole exome sequencing. The infant was born with pulmonary hypoplasia and suffered from severe respiratory distress immediately after birth, necessitating aggressive mechanical ventilation. At 2 weeks of age, multifocal brain hemorrhages were diagnosed by cerebral ultrasound and magnetic resonance imaging, together with increased tortuosity of cerebral arteries. Ensuing seizures were only partly controlled by antiepileptic drugs, and the infant became progressively comatose. Laboratory investigations revealed very low serum concentrations of copper and ceruloplasmin. No hair shaft abnormalities were detected by dermatoscopy or light microscopic analyses of embedded hair shafts obtained at 4 weeks of life. The infant died after redirection of care and elective cessation of invasive mechanical ventilation at 1 month of age. This case adds SLC31A1 to the genes implicated in severe hereditary disorders of copper transport in humans.

During a 1-year period, 4219 consecutive computerized tomograms (CT) were reviewed for basal ganglia calcification; 14 patients with such calcification were identified. Calcifications on CT scan were bilateral in 12 of these cases and unilateral in 2. All bilateral calcifications were symmetric. The globus pallidus was the site of calcification in 13 of the 14 patients. Bilateral dentate nucleus calcification was seen in one patient. Skull radiograms were normal in all but one. Patients had diverse symptoms that were often explained by other findings, suggesting that calcifications may be coincidental and that basal ganglia calcification may not be a nosologic entity. Disturbances of calcium metabolism were not found in these patients, minimizing the pathophysiologic significance of altered calcium metabolism and the need for extensive endocrinologic evaluation. The finding of basal ganglia calcification alone does not justify invasive diagnostic procedures. Extrapyramidal signs may be associated with basal ganglia calcification; parkinsonism associated with basal ganglia calcification differs from idiopathic parkinsonism in being resistant to levodopa therapy.

Cytochrome c oxidase (COX) deficiency is a phenotypically diverse group of diseases caused by variants in over 30 genes. Biallelic pathogenic variants in COX6B1 have been described in four patients to date with varying disease manifestations. We describe the clinical features and follow-up of a patient with a novel homozygous pathogenic variant in COX6B1 who presented acutely with severe encephalomyopathy associated with an infection. New findings include ophthalmological evaluation and follow-up of neuroradiological investigations. The novel p.Trp31Arg variant was predicted to be pathogenic in silico, and further functional analyses with biochemical analysis of mitochondrial function showed isolated COX deficiency. Muscle biopsy showed a specific lack of COX6B1 protein together with complex IV deficiency on western blot, enzyme histochemistry, and immuno-histochemistry.

Nonketotic hyperglycinemia (NKH) is a relatively well-characterized inborn error of metabolism that results in a combination of lethargy, hypotonia, seizures, developmental arrest, and, in severe cases, death early in life. Three genes encoding components of the glycine cleavage enzyme system-GLDC, AMT, and GCSH-are independently associated with NKH. We report on a patient with severe NKH in whom the homozygous pathogenic variant in AMT (NM_000481.3):c.602_603del (p.Lys201Thrfs*75) and the homozygous likely pathogenic variant in GLDC(NM_000170.2):c.2852C>A (p.Ser951Tyr) were both identified. Our patient demonstrates a novel combination of two homozygous disease-causing variants impacting the glycine cleavage pathway at two different components, and elicits management- and genetic counseling-related challenges for the family.

We report a female in her early childhood with autosomal recessive keratitis-ichthyosis-deafness (KID) syndrome, presenting with congenital erythroderma, sensorineural deafness and developmental delays. Genetic analysis revealed a novel homozygous pathogenic variant in the AP1B1 gene. Initiation of acitretin therapy led to significant dermatologic improvement without adverse effects so far. This case underscores the rarity of autosomal recessive KID syndrome and highlights acitretin's potential as a therapeutic option.

The presence of two different genetic conditions in the same individual is possible, especially in populations with consanguinity. In this case report, we present the coexistence of Artemis deficiency (OMIM 602450) and Three M (3M) syndrome (OMIM 273750). A 10-months-old male patient with neuromotor developmental delay was evaluated for immunodeficiency due to recurrent respiratory infections diarrhea and oral moniliasis from the age of 1.5 months. He had facial dysmorphism with rotated ears, flat nose and hypertelorism. Neurological examination revealed generalized hypotonia and mental motor delay. Immunological screening of the patient demonstrated mild lymphopenia, hypogammaglobulinemia, reduced number of CD3+ T cells (980 cells/mm3) and CD19+ B cells (35 cells/mm3). He was diagnosed with leaky T-B-NK+ SCID. Exome sequence analysis showed the presence of a homozygous pathogenic DCLRE1C variant [c.194C > T; p.T65I (NM_001033855)] and a homozygous pathogenic variant in OBSL1, a gene associated with 3M syndrome [c.3922C > T; p.R1308X (NM_001173431)]. Our proband died of sepsis and multiple organ failure. This case illustrates that different clinical findings in patients might not be explained with a single genetic defect, and consanguinity increases the change for coexistence of autosomal recessive diseases. Clinicians should consider exome sequencing to identify disease-causing mutations in patients with heterogeneity of clinical findings.

MITOCHONDRIAL DISEASES & METABOLIC MYOPATHIES: P.318 RBCK1-related disease: A rare multisystem disorder with polyglucosan storage, autoinflammation, recurrent infections, skeletal, and cardiac myopathy

There is increasing evidence that whole exome sequencing (WES) has a high diagnostic yield and is cost-efficient for individuals with neurological phenotypes. However, there is limited data on the use of WES in non-Western populations, including populations with a high rate of consanguinity. Retrospective chart review was performed on 24 adults with undiagnosed neurological symptoms evaluated in genetics and neurology clinics in a tertiary care facility on the Arabian Peninsula, and had WES between 2014 and 2016. Definitive diagnoses were made in 13/24 (54%) of cases. Of these, 5/13 (38%) revealed novel pathogenic variants. Of the known 19/24 (79%) consanguineous cases, diagnostic rate was slightly higher, 11/19 (58%) as compared to 2/5 (40%) among non-consanguineous cases. Autosomal recessive disorders comprised 10/13 (77%) of molecular diagnoses, all found to be due to homozygous pathogenic variants among consanguineous cases. WES in this cohort of adults with neurological symptoms had a high diagnostic rate likely due to high consanguinity rates in this population, as evidenced by the high diagnostic rate of homozygous pathogenic variants.

To report a homozygous pathogenic variant in PCSK1 in a boy affected with proprotein convertase 1/3 (PC1/3) deficiency. A male infant born to consanguineous Turkish parents presented in the first week of life with transient central diabetes insipidus, watery diarrhea, micropenis due to hypogonadotropic hypogonadism and GH deficiency, and transient asymptomatic hypoglycemia. Further endocrine defects gradually appeared, including central hypothyroidism and mild central hypocortisolism (at 1 year), central diabetes insipidus that reappeared progressively (at 2.5 years), and obesity (at 2 years). Whole-exome sequencing revealed a homozygous nonsense pathogenic variant (NM_000439.4) c. 595 C>T in exon 5 of PCSK1, not yet reported in cases of PC1/3 deficiency. To date, 26 cases of PC1/3 deficiency have been reported in the literature. All individuals had early and severe malabsorptive diarrhea and 83% had polyuria-polydipsia syndrome (before 5 years). Most (79%) had early onset obesity. Various endocrine disorders were present, including GH deficiency (44%), mild central hypothyroidism (56%), central hypogonadism (44%), central hypocortisolism (57%), and postprandial hypoglycemia (52%). When described (n = 15), proinsulin levels were consistently high: between 8 and 154 times the upper limit of normal (mean 74). We described a homozygous nonsense pathogenic variant (NM_000439.4) c. 595 C>T in exon 5 of PCSK1 in a boy with congenital PC1/3 deficiency. Elevated proinsulin could be useful in the diagnosis of this condition.

ObjectivesThe aim of this study was to investigate genetic outcomes, analyze the family experience, and describe the process of implementing genetic sequencing for children with profound sensorineural hearing loss (SNHL) at a tertial audiological center in southern Sweden. DesignThis is a prospective pilot study including eleven children with profound bilateral SNHL who underwent cochlear implant surgery. Genetic diagnostic investigation was performed with whole exome sequencing (WES) complemented with XON-array to identify copy number variants, using a manually curated gene panel incorporating 179 genes associated with non-syndromic and syndromic SNHL. Mitochondrial DNA (mtDNA) from blood was examined separately. A patient reported experience measures (PREM) questionnaire was used to evaluate parental experience. We also describe here the process of implementing WES in an audiology department. ResultsSix female and five male children (mean 3.4 years, SD 3.5 years), with profound bilateral SNHL were included. Genetic variants of interest were found in six subjects (55%), where three (27%) could be classified as pathogenic or likely pathogenic. Among the six cases, one child was found to have a homozygous pathogenic variant in MYO7A and two children had homozygous likely pathogenic variants in SLC26A4 and PCDH15, respectively. One was carrying a compound heterozygote frameshift variant of uncertain significance (VUS) on one allele and in trans, a likely pathogenic deletion on the other allele in PCDH15. Two subjects had homozygous VUS in PCDH15 and ADGRV1, respectively. In five of the cases the variants were in genes associated with Usher syndrome. For one of the likely pathogenic variants, the finding was related to Pendred syndrome. No mtDNA variants related to SNHL were found. The PREM questionnaire revealed that the families had difficulty in fully understanding the results of the genetic analysis. However, the parents of all eleven (100%) subjects still recommended that other families with children with SNHL should undergo genetic testing. Specifically addressed referrals for prompt complementary clinical examination and more individualized care were possible, based on the genetic results. Close clinical collaboration between different specialists, including physicians of audiology, audiologists, clinical geneticists, ophthalmologists, pediatricians, otoneurologists, physiotherapists and hearing habilitation teams was initiated during the implementation of the new regime. For all professionals involved, a better knowledge of the diversity of the genetic background of hearing loss was achieved. ConclusionsWhole exome sequencing and XON-array using a panel of genes associated with SNHL had a high diagnostic yield, added value to the families, and provided guidance for further examinations and habilitation for the child. Great care should be taken to thoroughly inform parents about the genetic test result. Collaborations between departments were intensified and knowledge of hearing genomics was increased among the staff.

Serum Fetuin-A Levels in Patients with Bilateral Basal Ganglia Calcification

Background and importance: Fahr’s syndrome is also known as idiopathic calcification of the basal ganglia. It is described as a rare, degenerative, neuropsychiatric disorder characterized by seizures, extrapyramidal, and neuropsychiatric symptoms as a result of symmetric and bilateral calcifications within the basal ganglia. Involvement of the nucleus pallidus, the putamen, the dentate nucleus of the cerebellum, and the hemispheric white matter at the base of the skull, are common radiological hallmarks of this syndrome. The calcification probably occurs due to lipid deposition and demyelinization. Clinical presentation: We present the case of a post thyroidectomy patient with hypoparathyroidism (HPT) with incidentally detected basal ganglia calcification (BGC). Retrospectively the patient was found to have hypocalcemia, secondary to a total thyroidectomy performed on her, 2 years ago. The second case was that of a 35 year old patient who presented with sudden onset of “worst headache of his life” since the previous night associated with multiple episodes of vomiting. Here we discuss our clinical dilemma and treatment strategy. Conclusion: In presence of BGC, HPT should be investigated, especially in patients who have undergone thyroidectomy, since in the early stage, the recovery could be expedited with a precise diagnosis and prompt treatment. This case report illustrated the benefits of calcium supplementation and calcitriol, even with the patient being in advanced stage of disease.

Fahr’s disease (FD) is a neurodegenerative disease whose aetiology is unknown, characterized by neuropsychiatric and motor problems associated with symmetrical, bilateral calcification of the basal ganglia. A drop in the metabolism and cerebral flow is deemed to be responsible for the onset of psychiatric and motor problems, cognitive deficit, painful symptoms and altered state of consciousness. The term Fahr’s syndrome (FS) is used when an etiological cause responsible for calcification can be identified. Fahr’s syndrome is associated with extremely diverse clinical conditions: calcium/phosphate metabolism disorders (hypo-hyperparathyroidism, pseudo-hypoparathyroidism), systemic lupus erythematosus, encephalitis and neoplasms [1]. Here, we describe clinical and radiological findings of a case of FS associated with micromolecular myeloma and hypothesize that bone remodelling could encourage the depositing of calcium at an intracerebral level as a result of an increase in the levels of alkaline phosphatase (ALP) and alteration of calcium levels. In January 2013, an 82-year-old woman was admitted to our hospital. The patient’s medical records showed a condition of severe osteoporosis with multiple collapsed vertebrae, dysphagia and rapidly ingravescent cognitive impairment over the last 18 months. No motor problems or psychiatric disturbances were reported. An acute onset of drowsiness made it necessary to hospitalize the patient, who appeared to be in generally serious conditions (Glasgow coma score (GCS) 10/15), and prompted us to perform a brain CT. The brain CT scan was negative regarding focal densitometric alterations and localized accumulation of blood, but showed dystrophic calcification of the dentate nuclei with bilateral occipital cortical calcification at the level of the calcarine cortex, as seen in FD (Fig. 1). Blood chemistry analysis also showed: kidney failure (GFR 13 ml/min); anaemia (Hb 9.5 g/dl; n.v. 12–16 g/dl); hypercalcaemia (13.3 mg/dl; n.v. 8.40–10 mg/dl) and hyperphosphatemia (5.9 mg/dl; n.v. 2.8–4.6 mg/dl); increase of ALP (123 U/l; n.v. 35–104 U/l) and inflammatory markers (VES 69 mm/h; n.v. 0–35 mm/h; PCR 18,600 lg/l; n.v. \5,000 lg/l). Protein electrophoresis test showed hypoalbuminemia (33.8 g/l; n.v. 40.2–47.6 g/l), increase of acute phase proteins and hypogammaglobulinemia (8 % n.v. 11.1–18.8 %). Alterations of the calcium and phosphate metabolism are the most common cause of FS. In our patient, the concomitance of calcification of the basal ganglia and hypercalcaemia led us to suspect a condition of secondary FS and hyperparathyroidism, but subsequent serum assays for parathormone (PTH) (40.7 pg/ml; n.v.15–65 pg/ml) and vitamin D (31 ng/ml; n.v. [30 ng/ml) were normal in both cases. During the clinical course, the patient was less drowsy and suffered extremely painful symptoms, visual analogue scale (VAS) 10/10; worsening renal function was also noted. Even though drowsiness and painful symptoms could be attributed to cerebral calcification, was ingravescent kidney failure simply a concomitant pathological condition or was there a link among the clinical picture, calcification of basal ganglia and renal dysfunction? A 24-h urine collection showed significant proteinuria (2,777 mg/ 24 h; n.v. 40–150 mg/24). The finding of proteinuria in the N. Gueli W. Verrusio (&) V. M. Magro M. Zaccone M. Cacciafesta Department of Anesthesiological, Cardiovascular, Respiratory, Nephrological, and Geriatric Sciences, Sapienza University of Rome, Viale del Policlinico 155, 00161 Rome, Italy e-mail: walter.verrusio@uniroma1.it

Cerebral folate transport deficiency due to folate receptor 1 gene (FOLR1) gene mutation results from impaired folate transport across the blood: choroidplexus: cerebrospinal fluid (CSF) barrier. This leads to low CSF 5-methyltetrahydrofolate, the active folate metabolite. We are reporting two children with this treatable cerebral folate transport deficiency. Eight years and 9-month-old female presented with delayed milestones followed by regression, seizures, and intention tremors. On examination child had microcephaly, generalized hypotonia, hyperreflexia, unsteady gait, and incoordination. Magnetic resonance imaging (MRI) of brain revealed dilated ventricular system and cerebellar atrophy. Computed tomography (CT) of brain showed brain calcifications. Whole exome sequencing was finally performed, revealing homozygous nonsense pathogenic variant in FOLR1 gene in exon 3 c.C382T p.R128W, confirming the diagnosis of cerebral folate deficiency. Twelve-year-old female child presented with global developmental delay since birth, myoclonic jerks and cognitive regression. Child had generalized hypotonia and hyperreflexia. Her coordination was markedly affected with intention tremors andunbalanced gait. CT brain showed bilateral basal ganglia and periventricular calcifications with brain atrophic changes. MRI brain showed a prominent cerebellar folia with mild brain atrophic changes. Genetic testing showed a homozygous pathogenic variant was identified in FOLR1 C.327_328 delinsAC, p.Cys109Ter. Both patients were started on intramuscular folinic acid injections with a decrease in seizure frequency. However, their seizures did not stop completely due to late initiation of therapy. In conclusion, cerebral folate transport deficiency should be suspected in every child with global developmental delay, intractable myoclonic epilepsy, ataxia with neuroimaging suggesting cerebellar atrophy and brain calcifications. Response to folinic acid supplementation is partial if diagnosed late and treatment initiation is delayed.

BackgroundIdiopathic basal ganglia calcification (IBGC) is a genetic disorder of the nervous system commonly known as Fahr disease. IBGC patients with a genetic background are considered to have primary familial brain calcification (PFBC), also known as familial basal ganglia calcification (FBGC), or familial Fahr disease. It is a rare degenerative neurological disorder characterized by extensive bilateral basal ganglia calcification that can lead to a range of extrapyramidal symptoms and neuropsychiatric manifestations. Studies have suggested that more than 50 variants of SLC20A2 gene mutations account for approximately 50% of IBGC cases. There is a wide spectrum of mutation types, including frameshift, nonsense, and splice site mutations in addition to deletion and missense mutations. Here we report a case of familial basal ganglia calcification caused by a frameshift mutation in the SLC20A2 gene. We identified a heterozygous mutation in the SLC20A2 gene, c.1097delG (p.G366fs*89). To our knowledge, this mutation site has not been reported before.Case presentationA 57-year-old male patient was admitted to the hospital with “unstable walking and involuntary movements between the eyes and eyebrows for 6 months”. Based on the patient’s family history, symmetrical calcification foci in the bilateral caudate nucleus head, thalamus, cerebellum and parietal lobe indicated by head CT, and gene test results, the diagnosis of familial Fahr disease caused by mutations in the SLC20A2 gene, c.1097delG p.G366fs*89) was confirmed.ConclusionFor the first time, we identified c.1097delG (p.G366fs*89) as a frameshift mutation in the IBGC family. This frameshift mutation caused the condition in this family of patients. This mutation not only broadens the range of known SLC20A2 mutations but also aids in the genetic diagnosis of IBGC.