Compound Heterozygous Research Articles

Molecular and Clinical Spectrum of Hemoglobin D: An Experience at a Tertiary Care Diagnostic Center

Objective: To determine the clinical and molecular pattern of Hemoglobin D in patients presenting at tertiary care hospital. Study Design: Cross-sectional study. Place and Duration of study: Department of Hematology, Armed Forces Institute of Pathology, Rawalpindi Pakistan, from Jul 2020 to Mar 2021. Methodology: An automated cell analyzer was used to determine the whole blood count and red cell indices. D-10 BIORAD HPLC was used for quantitative assessment of Hb A, Hb F, Hb D and Hb A2. Where D-10 BIORAD HPLC showed an abnormal Hb D, capillary electrophoresis was performed using Sebia Capillary 2 Flex Piercing. Chelex DNA Extraction method was used. Molecular analyses for the confirmation of homozygosity and heterozygosity were done using Polymerase Chain Reaction (PCR) amplification. The clinical symptoms of the patients such as anemia, jaundice, pallor, weakness, hepatomegaly and splenomegaly were also noted Results: Among 90 patients, Hemoglobin D trait was found in 78(80.4%) of the patients out of which HbD-Punjab was seen in 57(73%) and HbD-Iran was found in 21(27%). Compound Heterozygotes (HbD/β) was found in 17(17.5%) and Compound Homozygous HbD/D was found in 02 (2.1%). All HbD-Punjab and HbD-Iran traits patients were asymptomatic, and few clinical symptoms were found in Compound Heterozygotes (HbD/β) and Homozygous HbD/D. Conclusion: Collective clinical history records, full blood count and electrophoresis and molecular results allow for the conclusive detection of the variant of Hemoglobin D. More multicenter, organized and detailed studies with larger sample size are required to draw concrete conclusions.

Canine Multiple System Degeneration Associated with Sequence Variants in SERAC1

Canine multiple system degeneration (CMSD) is an early onset, progressive movement disorder affecting Kerry Blue Terriers and Chinese Crested dogs. The associated pathologic lesions include degeneration of the cerebellum, caudate nucleus, and substantia nigra. CMSD is inherited as an autosomal recessive trait in both dog breeds. Previous linkage mapping localized the CMSD locus to a 15 MB region on canine chromosome 1 (CFA1). Next-generation sequencing was used to generate whole-genome sequences from the DNA of an affected dog from each breed. The resulting sequence reads were aligned to the NCBI canine reference genome (build 3.1). Among the homozygous sequence variants within the CFA1 target region, a nonsense variant in exon 15 of SERAC1 was identified in the affected Kerry Blue Terrier, while in the Chinese Crested dog, a 4 bp deletion in the SERAC1 exon 4 acceptor splice site was found. RT-PCR showed that this deletion resulted in exon 4 skipping. Genotyping of large cohorts of Kerry Blue Terriers and Chinese Crested dogs for the respective breed-specific SERAC1 variants showed complete concordance between genotype and disease phenotype. Genotype–phenotype concordance was also observed in offspring generated by cross breeding between SERAC1-heterozygous Kerry Blue Terrier and Chinese Crested dogs, with only the compound heterozygotes exhibiting the disease phenotype, further confirming the recessive inheritance of CMSD. Variants in human SERAC1 are associated with disorders with a range of ages of disease onset and patterns of clinical signs, but that are all characterized by movement abnormalities similar to those of the dogs with CMSD. Canine CMSD could serve as a valuable model to elucidate the mechanisms underlying SERAC1-deficiency disorders and to evaluate potential therapeutic interventions.

Distribution and classifications of PKHD1 gene variants in a Turkish population using the next generation sequencing method.

Autosomal recessive polycystic kidney disease is an inherited kidney disease. This study aims to detect rare and common DNA variants of the PKHD1 gene using next-generation sequencing (NGS) and to classify them in terms of being pathogenic according to The American College of Medical Genetics and Genomics. NGS analysis was performed on the DNA of 304 patients who were referred to Ege University Molecular Medicine Laboratory with suspected polycystic kidney disease. As a result, a total of 82 different DNA variants, 16 of which were novel, were detected. The breakdown of the variants found is as follows: 73 (89.02%) were missense variants, six (7.32%) nonsense variants, two (2.44%) frameshift deletions, and one (1.22%) nonframeshift deletion. According to The American College of Medical Genetics and Genomics classification of these variants, 26 were benign (Class 5), two were likely benign (Class 4), 36 were of uncertain significance (Class 3), and nine were likely pathogenic (Class 2), nine of which are pathogenic variants (Class 1). Heterozygosity was found in 39 (63.9%) patients, homozygosity in six (9.8%) patients, compound heterozygosity in 12 (19.7%) patients, and complex genotype in four (6.6%) patients in which variants in Class 1, Class 2 and Class 3 were determined according to ACMG classification. When the exon distributions of the DNA variants detected in the PKHD1 gene were analyzed, the most common exons of the DNA variant are exon 32 (n = 9), exon 58 (n = 8), exon 67 (n = 6), exon 61 (n = 5), 30 exons (n = 4). This fast and economical molecular diagnostic approach will provide a reliable prenatal diagnostic option, enabling definitive disease diagnosis and the identification of carriers.

Targeted long-read sequencing identifies missing pathogenic variant in unsolved 11β-hydroxylase deficiency

Background11β-hydroxylase deficiency (11β-OHD), caused by homozygosity or compound heterozygosity CYP11B1 variants, is the second most common cause of congenital adrenal hyperplasia (CAH). Due to the high degree of sequence identity between CYP11B1 and CYP11B2, chimeric genes, and complex structural variants (SVs), the conventional approach to gene testing for 11β-OHD is facing challenges. The study aimed to clarify the underlying genetic causes of two siblings of a Chinese family with 11β-OHD.MethodsPeripheral blood samples and clinical information were collected from subjects and their family members. Sex steroid concentrations were measured using LC-MS/MS. Long-range PCR-based next-generation sequencing (NGS), PCR assay and target long-read sequencing were used to detect the pathogenic variants.ResultsEarly onset hypertension, increased serum levels of adrenocorticotropin (ACTH), progesterone, testosterone, and decreased cortisol and potassium were detected in both affected siblings. Long-range PCR-based NGS identified a heterozygous missense variant (NM_000497.4:c.281 C > T, p.P94> L) in CYP11B1 gene in the two siblings. PCR detected no chimeric CYP11B2/CYP11B1 gene. We finally identified a second pathogenic variant in CYP11B1 gene via target long-read sequencing (T-LRS). This novel variant was a deletion-insertion variant and located chr8:143957269–143,957,579 (hg19) with the insertion of ‘ACAG’ (NM_000497.4:c.954 + 78_980delinsACAG), which was in trans with CYP11B1: c.281 C > T.ConclusionsOur study suggests that the integrated long-range PCR-based NGS and T-LRS seem to be the most reliable and accurate method for 11β-OHD genetic diagnosis and carrier sequencing.

Genetic analysis of a child with autosomal recessive primary microcephaly due to variant of ASPM gene and a literature review

To explore the clinical and genetic characteristics of a child with autosomal recessive primary microcephaly (MCPH). A case study has been carried out on a boy who had presented at the Inner Mongolia Maternity and Child Health Care Hospital for microcephaly and mental deficiency in September 2022. Prenatal ultrasound images were retrospectively analyzed, and whole exome sequencing and Sanger sequencing were carried out for his family. A literature review was also carried out using keywords such as "ASPM gene", "microcephaly", "prenatal diagnosis", "primary microcephaly", "ASPM", "MCPH5", "MCPH", "autosomal recessive microcephaly", and "prenatal diagnosis on ultrasonography" on the PubMed database, Wanfang Data and China National Knowledge until September 2023. This study was approved by the Inner Mongolia Maternity and Child Health Care Hospital (Ethics No. 2021-093-1). The proband had shown progressive reduction in biparietal diameter (BPD) and head circumference (HC) during the fetal period. He was found to harbor compound heterozygous variants of the ASPM gene, which included a paternally derived c.8044C>T (p.R2682X) and a maternally derived c.8652dup (p.A2885Sfs*35). Both variants were classified as pathogenic (PVS1+PM2_Supporting+PP4; PVS1+PM2_Supporting+PM3) based on the guidelines from the American College of Medical Genetics and Genomics (ACMG). For other fetuses in his family, prenatal ultrasound and genetic testing were all normal. Literature research has identified 11 relevant articles, which included 14 MCPH cases. All of the MCPH5 cases had shown various degrees of reduced BPD/HC on fetal imaging (100%, 15/15). Developmental delay, intellectual disability, and attention deficits were noted in all survived cases, with one case having seizures (12.5%, 1/8). Their genotypes had included homozygotes (46.2%, 6/13) and compound heterozygotes (53.8%, 7/13) for nonsense variants (45%, 9/20) and frameshifting variants (55%, 11/20). The compound heterozygous variants c.8044C>T (p.R2682X) and c.8652dup (p.A2885Sfs*35) of the ASPM gene probably underlay the reduced BPD and HC in this proband with MCPH.

8015 Growth Hormone Axis Dysfunction in PMM2-CDG: Exploring the Role of Dynamic Tests for the Management of Short Stature in Two Pediatric Cases

Abstract Disclosure: G. Del Medico: None. E. Procopio: None. L. Ferri: None. A. Barbato: None. A. Morrone: None. S. Stagi: None. PMM2-CDG is the most prevalent congenital disorder of glycosylation (CDG) and is caused by defective phosphomannomutase2 (PMM2) activity. According to the 2019 guidelines, approximately half of PMM2-CDG patients exhibit short stature and low serum levels of insulin-like growth factor-1 (IGF-1), IGF binding protein 3 (IGFBP3), and acid-labile subunit (ALS). Despite this, there is no expert consensus on the endocrinological management of this condition. We investigated the growth hormone (GH) axis in two 12-year-old female patients with PMM2-CDG. The first patient was compound heterozygote for the most common PMM2 gene variants in Italy, p.(Leu32Arg) and p.(Arg141His). She presented with short stature (< 2 Standard Deviation Score, SDS) and low serum levels of IGF-1 and IGF-BP3 (< 2.5° for age and sex). Bone age was significantly delayed. Tanner stage was prepubertal. Somatotropic response to GH stimulation testing (Levodopa) was normal. After the IGF-1 generation test with recombinant GH, serum IGF-1 increased by 115%. The second patient was compound heterozygote for the known PMM2 pathogenetic variant p.(Ala108Val) and the novel p.(Thr171Asnfs*11) variant (only case described in literature). She presented short stature (< 2 SDS) with near-to-normal IGF-1 and IGF-BP3 serum levels (2.5° for age and sex). Bone age was slightly delayed. Tanner stage was prepubertal. She also exhibited severe obesity, hypertriglyceridemia, and hepatic steatosis. Her somatotropic response to two GH stimulation tests (Levodopa and Arginine) was deficient, probably because of her significant overweight. IGF-1 serum levels didn’t increase after the IGF-1 generation test. Hypoglycosylation in PMM2-CDG impairs the IGF1 system on multiple levels. It destabilizes the ternary complex formed by IGF-1 and glycoproteins IGFBP3 and ALS, therefore reducing the half-life of circulating IGF-1. Hypoglycosylation also reduces IGF1 production by impairing its precursor proIGF-1Ea and its cellular secretion. As a result, PMM2-CDG patients have GH insensitivity, with normal GH production but low levels of IGF-1. However, there is a lack of information in the literature on the use of dynamic tests and hormonal therapies (GH and rhIGF-1) in CDG. The IGF-1 generation test in our patients showed partial GH sensitivity in the first patient and GH insensitivity in the second patient. These observations suggest variability. Some PMM2-CDG patients may benefit from an extended trial with GH therapy, while for GH-insensitive patients a trial with recombinant IGF-1 might be considered. This is one of the first reports that explores the potential role of dynamic tests in PMM2-CDG. As the biochemical effects of hypoglycosylation on the GH-IGF1 pathway are becoming clearer more clinical research is needed to reach a consensus on the management and treatment of short stature in these patients. Presentation: 6/3/2024

A TBC1D24 gene variant coincides with STRC compound heterozygosity in a family with hearing loss: a case report

BackgroundHearing loss is a common inborn neurosensory condition. Hearing loss is very heterogeneous, and while screening programs exist for children, adolescents and adults with late-onset hearing loss often do not get referrals to geneticists.ObjectiveTo diagnose the cause of hearing impairment in two related late-onset hearing loss patients—father and son—on a molecular level. Both underwent audiological examinations, and both had moderate hearing loss.Case presentation.We used massive parallel sequencing, Sanger sequencing, MLPA, and standard audiological methods. We identified an inherited autosomal dominant likely causative variant in the TBC1D24 gene of both patients. They did not show any other TBC1D24 spectrum-related symptoms. Furthermore, the younger patient was found to be compound heterozygous for two variants in STRC gene.ConclusionsOnly a few dozen TBC1D24 hearing loss patients have been reported. On the contrary, STRC is a common hearing loss cause. We speculate that in the younger patient, the phenotype is caused by a combination of effects of both genes. The older patient’s phenotype is more likely caused only by the TBC1D24 variant. We believe that more attention should be paid to adolescent and adult-onset hearing loss patients, and more frequent referrals to geneticists are warranted.

NBEAL2 gene mutations do not always lead to gray platelet syndrome: A case report.

Gray platelet syndrome (GPS) is a rare disease caused by homozygosity and compound heterozygosity for autosomal mutations on the NBEAL2 gene, which is characterized by a deficiency of platelet α-granules, bleeding symptoms. However, in this study, we report 2 NBEAL2 gene mutations in an easy bruising family without gray platelet and bleeding. A 33-year-old female nurse sought admission to our laboratory due to a tendency to bruise easily and unwell in daily life. However, there are no signs of petechiae or excessive bleeding in her daily life. Coagulation tests, routine blood tests and platelet staining of blood smears were all normal. The whole exome sequencing and Sanger sequencing were used to identify the causative variant of the patient. Furthermore, the morphology of platelets was examined using electron microscopy. Whole exome sequencing revealed the presence of 2 mutations in the NBEAL2 gene: p.Thr365fs and p.Ala310Thr. This prompted the consideration of a GPS diagnosis. However, platelet electron microscopy did not identify any abnormalities, leading to the exclusion of GPS. These 2 NBEAL2 gene mutations (p.Thr365fs and p.Ala310Thr mutations) do not affect the degranulation of platelets.

Annual change in eGFR in renal hypouricemia: a retrospective pilot study.

Extremely low uric acid (UA) levels or increased urinary UA (Uua) excretion might be risk factors for kidney disease in renal hypouricemia (RHU) patients, but their relationship with kidney dysfunction is unclear. This study investigated time-dependent changes in eGFR in RHU patients. This multicenter retrospective study assessed UA metabolism and changes in eGFR (median 5.5years) in 13 RHU patients. We then compared eGFR change in 7 of 13 RHU patients whose eGFR could be measured for 4years with those in normouricemic group (n = 31). In addition, 7 RHU patients were divided into two groups based on URAT1 gene mutations: homozygote and compound heterozygote mutations (Homo/Com group, n = 3), and wild-type and heterogeneous mutations (WT/Hetero group, n = 4). In 13 RHU patients, the median and mean serum UA (SUA) were 0.8 (0.4-2.5) and 1.1 ± 0.7mg/dL. The median and mean Uua were 44.3 (12.7-141.1) and 49.7 ± 36.2mg/dL. The median and mean urinary urate clearance (Cua/Ccr) were 46.8 (11.3-73.6) and 43.3 ± 19.7%. Over 4years, eGFR did not change in the RHU group but declined in the normouricemic group. Annual mean eGFR decline and change rate in the RHU group were the same as those in the normouricemic group (- 1.09 ± 1.11 vs. - 1.09 ± 1.92mL/min/1.73 m2/year, p = 0.996) (- 1.74 ± 1.96 vs. - 1.36 ± 2.10%, p = 0.664). And no significant difference was found in eGFR decline or change rate between Homo/Com and WT/Hetero groups (- 0.33 ± 1.03 vs. - 1.67 ± 0.85mL/min/1.73 m2/year, p = 0.116) (- 0.61 ± 1.62 vs. - 2.59 ± 1.91%, p = 0.210). RHU from URAT1 genetic mutation may not show eGFR decline over 4 consecutive years.

Commentary on Negative Sweat Chloride Testing in the Setting of a Positive Newborn Screen and CFTR Compound Heterozygosity.

Commentary on Negative Sweat Chloride Testing in the Setting of a Positive Newborn Screen and CFTR Compound Heterozygosity.

Intrafamilial neurological phenotypic variability due to either biallelic or monoallelic pathogenic variants in CACNA1A.

Pathogenic heterozygous variants in CACNA1A are associated with familial hemiplegic migraine, episodic ataxia type 2 and spinocerebellar ataxia type 6, and more recently, neurodevelopmental disorders. We describe a severe, early-onset phenotype including severe muscular hypotonia, early-onset epileptic seizures, apnoea, optic atrophy and dysphagia in three siblings carrying compound heterozygous frameshift variants in CACNA1A. Two male patients died at the age of 5 or 14 months of suspected SIDS or severe developmental epileptic encephalopathy (DEE) with refractory seizures and apnoea. A male child (index patient) developed severe early-onset DEE including seizures and ictal apnoea at the age of 4 weeks. Another male child developed generalized epilepsy and mild intellectual impairment in late infancy, and his mother and his maternal uncle were identified as carriers of a known CACNA1A pathogenic variant [c.2602delG heterozygous, p. (Ala868Profs*24)] with a diagnosis of episodic ataxia type 2. This maternal pathogenic variant c.2602delG was detected in the index patient and child 2. Trio-Exome sequencing identified an additional heterozygous pathogenic variant in the CACNA1A gene, c.5476delC, p.(His1826Thrfs*30) in the index patient and child 2, which was inherited from the asymptomatic father. In conclusion, the novel compound heterozygosity for two frameshift pathogenic variants, maternally [c.2602delG, p.(Ala868Profs*24)] and paternally [c.5476delC, p.(His1826Thrfs*3)] is associated with a severe phenotype of early-onset DEE. This observation highlights the necessity of additional analyses to clarify unusual phenotypes even if a pathogenic variant has already been identified, and expands the clinical spectrum of CACNA1A-related disorders.

Global Presence and Penetrance of CSF1R-Related Disorder.

To highlight the worldwide presence of CSF1R-related disorder (CSF1R-RD), discuss its penetrance, and provide the first haplotype analysis. Data on patients worldwide were collected, including demographics, genotype, family history, and clinical status. For haplotype analysis, polymorphisms of short tandem repeats in 3 distinct families with CSF1R p.Ile794Thr variant were examined. Nineteen new patients were included, at a mean age of 38.7 years (ranging from 11 to 74 years), from 14 families from the Americas, Asia, Australia, and Europe, including the first from Mexico, North Macedonia, and Ukraine. Fifteen CSF1R variants were found, including 8 novel. Three patients were compound heterozygotes with disease onset at 1, 4, and 22 years. Patients with heterozygous CSF1R variants developed symptoms at a mean of 39.0 years (range 8-71 years). Four patients died at a mean of 3.3 years from onset (range 2-5 years). Negative family history was noted in 7 patients. In haplotype analysis, 2 families exhibited shared haplotype encompassing ∼6-Mb region downstream of the CSF1R while the third family displayed a different haplotype. CSF1R-RD has a global prevalence. The reasons for negative family history include de novo variants (as shown by the haplotype analysis), mosaicism, and incomplete penetrance, which are possibly modulated by environmental and genetic factors.

Variants in the β-globin locus are associated with pneumonia in African American children

In African American adults, the strongest genetic predictor of pneumonia appears to be the A allele of rs334, a variant in the β-globin gene which in homozygous form causes sickle cell disease (SCD). No comparable studies have been done in African American children. We performed genome-wide association analyses of 482 African American children with documented pneumonia and 2048 African American controls using genotypes imputed from two reference panels: 1000 Genomes (1KG) (which contains rs334) and TOPMed (does not contain rs334). Using 1KG imputed genotypes, the most significant variant was rs334 (A allele (OR = 2.76 (2.21-3.74), p=5.9x10-19); using TOPMed imputed genotypes the most significant variant was rs2226952, found in the β-globin locus control region (G allele (OR =2.14 (1.78-2.57), p = 5.1x10-16). After conditioning on rs334, the most strongly associated variant in the β-globin locus was rs33930165, (allele T, 1KG: OR=4.09 (2.29-7.29), p=1.7x10-6; TOPMed: OR=3.58 (2.18-5.90), p=4.7x10-7), which as a compound heterozygote with rs334 A allele can cause SCD. To compare the power of different sample sets we developed a way to estimate the power of sample sets with different sample sizes, genotype arrays and imputation platforms. Our results suggest that in African American children the strongest genetic determinants of pneumonia are those that increase the risk of SCD.

MCM9 compound heterozygosity in an adolescent with premature ovarian insufficiency.

Delayed puberty in girls is often related to late maturation but is occasionally the first sign of premature ovarian insufficiency (POI). POI is a condition that affects ovarian function and fertility, and its etiology is unknown in most cases. Genetic factors have recently been identified in 20-25% of women with POI, involving genes that regulate various aspects of ovarian development and maintenance. We report a case of delayed puberty due to POI in an adolescent from a non-consanguineous family who carried two variants in the MCM9 gene. MCM9 is essential for DNA replication and repair, and its dysfunction can lead to chromosomal instability and ovarian failure. Our case highlights the importance of targeted gene panel analysis, particularly in POI patients with negative autoimmunity screening, and evidence of ovarian or uterine dysgenesis on pelvic imaging. Delayed puberty in girls is often self-limiting, but it can also indicate underlying conditions with lifelong implications, such as premature ovarian insufficiency (POI). Patients with POI, negative autoimmune screening, a normal karyotype, and no FMR premutation should undergo further genetic testing, preferably through targeted gene panels. Compound heterozygous variants in MCM9 can cause POI, presenting with delayed puberty and primary amenorrhea in girls without a consanguineous family.

Insights from a Wolfram syndrome cohort: clinical and molecular findings from a specialized diabetes reference center.

Considering the rarity and clinical and molecular diversity of Wolfram syndrome (WS), the objective of this study was to identify patients with a clinical presentation suggestive of WS following up at a single Brazilian diabetes service and analyze their clinical and molecular characteristics. The study included all patients with a clinical presentation of WS following up between 1991 and 2022 with early-onset diabetes mellitus and other WS signs and symptoms. A retrospective analysis was conducted, including patients' age, sex, consanguinity, age at symptom onset, diagnosis of diabetes mellitus, optic atrophy, diabetes insipidus, neurological and psychiatric disorders, hearing loss, urinary disorders, hypogonadism, and WFS1 molecular analysis. Eight patients were identified, all of whom were diagnosed with diabetes mellitus at an average age of 3.7 years. Optic atrophy, diabetes insipidus, and hearing loss were common, while psychiatric and neurological alterations were observed in some cases. Genetic analysis revealed pathogenic variants in homozygosity or compound heterozygosity. The most frequent variant was p. Val412Serfs29, present in five of the seven families. This study represents the second-largest Brazilian sample of WS and is the first cohort from a single center in Southeast Brazil. The patients had an early, severe, and complete clinical presentation. The genetic variants identified were consistent with previous literature descriptions. The variant p. Val412Serfs29 was particularly common in this cohort, highlighting its relevance in the region.

Prenatal diagnostic errors in hemoglobin Bart's hydrops fetalis caused by rare genetic interactions of α-thalassemia.

To describe rare genetic interactions of α-thalassemia alleles causing Hb H disease and Hb Bart's hydrops fetalis which could lead to diagnostic errors in a routine practice. Hematological and molecular characterization were carried out in a Thai family with a risk of having fetus with Hb Bart's hydrops fetalis. Both parents were found to be the thalassemia intermedia patients associated with unusual forms of Hb H disease. DNA analysis of common α-thalassemia mutations in Thailand identified α+-thalassemia (-α3.7 kb del) and unknown α0-thalassemia in the father and α0-thalassemia (--SEA) with unknown α+-thalassemia in the mother. Fetal DNA analysis unlikely identified a homozygosity for α0-thalassemia (--SEA/--SEA). Further analysis identified that the father carried a rare South African α0-thalassemia in combination with α+-thalassemia (--SA/-α), whereas the mother was a patient with Hb H-Queens Park disease (--SEA/ααQP). The fetus was, in fact, a compound heterozygote for (--SA/--SEA). As shown in this study, routine screening for α-thalassemia at prenatal diagnosis in the region should include both common and rare α0-thalassemia alleles found in the population to effectively prevent a fatal condition of Hb Bart's hydrops fetalis syndrome.

Characterization of the Retinal Phenotype Using Multimodal Imaging in Novel Compound Heterozygote Variants of CYP2U1

Characterization of the Retinal Phenotype Using Multimodal Imaging in Novel Compound Heterozygote Variants of CYP2U1

Molecular investigation of MEFV gene polymorphisms among patients with familial mediterranean fever-like symptoms.

The diagnosis of familial Mediterranean fever (FMF) is primarily based on clinical standards. The purpose of this study was to investigate the relevance of Mediterranean fever (MEFV) genetic testing in the diagnosis of FMF as well as to identify the most frequent variant alleles and their relationship to clinical symptoms in Egyptian patients. Egyptian patients with a clinical suspicion of having FMF were studied in order to determine MEFV genotypes. Each patient was meticulously evaluated through an extensive collection of their medical history, a thorough clinical examination, and a series of laboratory tests, encompassing CBC, ESR, and CRP measurements. The MEFV variant screening procedure included the use of reverse dot blot hybridization. The average age of our patients when they were given a diagnosis was 22.8 ±1.404 years old. The predominant clinical manifestations identified were abdominal pain, fever, and arthralgia. Molecular interrogation of the MEFV gene unveiled that a significant proportion of the cohort, constituting 72 individuals (60%), displayed heterozygosity, whereas a smaller fraction, comprising 12 subjects (10%), demonstrated homozygosity and an equivalent number (10%) exhibited compound heterozygosity. Pertaining to the distribution of allele variants, E148Q emerged as the most prevalent, succeeded by M694I, accounting for 12.5% of the cases, and M680I (G/A), representing 10.41%. This notable prevalence of heterozygous genotypes among the Egyptian demographic, preliminarily identified as potential FMF cases, underscores the imperative for molecular diagnostics to enhance the precision of FMF identification.

Congenital bile acid synthetic disorder type 3 caused by CYP7B1 gene variation in 2 cases and literature review

Objective: To summarize the clinical features and genetic characteristics of Congenital bile acid synthetic disorder type 3 (BASD3) disorder caused by CYP7B1 gene variation. Methods: This was a case series study. Clinical data and genetic results of 2 cases of congenital bile acid synthetic disorder type 3 caused by CYP7B1 gene variations in the Department of Infectious Diseases, Children's Hospital of Fudan University at Xiamen and Department of Pediatrics, Women and Children's Hospital, School of Medicine, Xiamen University from January 2021 to December 2023 were retrospectively collected and analyzed. Literature up to December 2023 was searched from electronic databases of China National Knowledge Infrastructure (CNKI), Wanfang Data and PubMed with the combined keywords of " Congenital bile acid synthetic disorder type 3""Oxysterol 7-alpha-hydroxylase""Oxysterol 7α-Hydroxylase Deficiency""BASD3" and "CYP7B1 liver" both in Chinese and English. The main clinical features and genetic characteristics of BASD3 disorder caused by CYP7B1 gene variations were summarized. Results: Two BASD3 patients, 1 male and 1 female, were admitted at the ages of 3 months and 18 days, and 2 months and 7 days, respectively. Both patients presented with neonatal cholestasis and hepatomegaly. Biochemical evidence indicated direct hyper-bilirubinemia with elevated aminotransferase levels, while gamma-glutamyltransferase (GGT) and total bile acid levels were normal or nearly normal. Patient 1 was a compound heterozygotes of the CYP7B1 gene variants c.525-526insCAAGTTGG(p.Asp176GInfs*15) and c.334C>T(p.Arg112Ter). Patient 1 jaundice resolved and liver function tests normalized after oral administration of chenodeoxycholic acid (CDCA). Patient 2 was homozygous for variant c.334C>T(p.Arg112Ter) in CYP7B1 gene. Patient 2 was in liver failure status already and not reactive to oral CDCA administration. Patient 2 received living-related liver transplantation for enhanced abdominal CT revealed a liver tumor likely vascular origin. Literature review revealed no cases of BASD3 reported in Chinese literature, including 2 patients in this study, while 12 patients (9 males and 3 females) were reported in 9 English literatures. All of the 12 manifested jaundice and hepatosplenomegaly in infancy, with cirrhosis, liver failure, kidney enlargement, hypoglycemia, and spontaneous bleeding in some cases, polycystic kidney disease was demonstrated in 5 cases of them. The c.334C>T (p.Arg112Ter) of the CYP7B1 gene was homozygous in 4 cases and compound heterozygous in 2 cases. Among the 12 children, 6 cases received CDCA treatment, while 6 cases not. Four survived with their native liver in the 6 cases who received CDCA therapy, while none in the 6 cases not received CDCA therapy. Conclusions: BASD3 is a rare hereditary cholestatic disorder. Markedly elevated levels of conjugated bilirubin and aminotransferases, with normal or nearly normal GGT and total bile acid levels can serve as diagnostic clue. c.334C>T is the most common pathogenic variant of the CYP7B1 gene. Timely administration of CDCA may save the liver.

Low penetrance of frequent ATP7B mutations explains the low prevalence of Wilson disease. Lessons from real-life registries.

Background & AimsWilson disease (WD) is a copper metabolism disorder caused by mutations in ATP7B gene, with significant clinical variability. Several studies have analyzed the prevalence and penetrance of mutations. We evaluated both characteristics for our more frequent mutations. MethodsEvaluation of 260 patients from the National Registry: clinical, analytical and genetic data. Estimation of homozygotes and total cases according to Hardy-Weinberg equilibrium and comparison with Registry records. ResultsThe estimated number of homozygotes were higher than registered: p.Met645Arg (1949/6), p.His1069Gln (20/8), p.Leu708Pro (63/24) and p.Gly869Arg (147/0). p.Met645Arg homozygotes presented less cirrhosis at diagnosis, extrahepatic disease and Kayser-Fleischer ring (KFR) and more presymptomatic cases and diagnosis after 40 years of age than p.Leu708Pro and p.His1069Gln homozygotes. p.Met645Arg homozygotes presented more late diagnosis than p.Met645Arg compound heterozygotes. Compound heterozygotes carrying p.Met645Arg or p.Gly869Arg showed less cirrhosis at diagnosis, KFR and neurological symptoms and more hepatic and presymptomatic cases, despite clearly low ceruloplasmin levels. The estimated prevalence was 1:3.785, predicting more than 10.500 patients. ConclusionsThe widespread mutations p.Met645Arg and p.Gly869Arg show low penetrance. WD might be underdiagnosed in Spain due to less severe phenotype of the most frequent mutations, a crucial fact to avoid misdiagnosis and to offer early therapy.