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The development of high-throughput technologies has enabled Expanded Carrier screening (ECS) as a more comprehensive and extensive approach for high-risk populations. The available methods of ECS are population-targeted gene-panels according to ethnicity, however these panels should be planned according to a real-world data evaluation. In this study, we estimate the frequency of pathogenic variants for autosomal-recessive and X-linked conditions in Exome Sequencing-ES data for a 176 gene panel proposed from ACMG and ACOG in a Greek cohort. ES data from 1000 unrelated individuals was evaluated for pathogenic SNVs and CNVs. Variants were filtered using 5% Minor Frequency Allele (MAF), ClinVar submissions, and classification with ACMG criteria. For the at-risk couple rate, we hypothesized that both parents carried variants in the same gene. It is noted that many common conditions (hemoglobinopathies, SMA, Fragile-X) may escape NGS-based detection as they require alternative methods for optimal detection. Amongst 1000 participants, 32% were heterozygous for at least one disorder and 14% for two or more, whereby 393 unique pathogenic/likely pathogenic heterozygous variants were identified. We calculated that 1.6% of couples have a risk for at least one AR condition, which means that for 85,000 births per year, 1380 couples require genetic counseling. This study provides data confirming that the ACMG/ACOG ECS list of 176 genes is suitable for carrier screening in Greece, and aids counseling prospective parents for residual risk, however it should be supported by appropriate interpretation and reproductive options, as well as ancillary genetic testing methods., Competing Interests: Competing interests: The authors declare no competing interests. Ethical approval: Ethical approval was obtained from the Bioethics and Ethics committee of the St. Sophia’s Children’s Hospital, National and Kapodistrian University of Athens (Approval number: 3669/12-02-18, 22140/10-09/2024). Written informed consent was obtained from all participants or their legal guardians., (© 2024. The Author(s), under exclusive licence to European Society of Human Genetics.)

Nablus mask-like facial syndrome (NMLFS) is a rare condition characterized by unique facial features, initially described in a 4-year-old boy from Nablus, Palestine. These features include expressionless facial appearance, tight facial skin, blepharophimosis, sparse eyebrows, and a flat nose. Genetic studies have identified a deletion of 8q22.1 as the cause of the syndrome, however while 26 patients have been reported with the deletion, only 13 displayed the characteristic facial features. Here we report on a 35-year-old male with 8q21.3-q22.1 deletion identified by whole exome sequencing and Chromosomal microarray analysis (CMA) that presents with typical and atypical features, including neurodevelopmental disorder, mild facial features, and myopathy, which has not been described in a patient with NMLFS to date. Further research will be required to understand the underlying pathogenetic mechanism of this rare genetic disorder., (© 2024 The Author(s). American Journal of Medical Genetics Part A published by Wiley Periodicals LLC.)

Alport syndrome (AS) is a hereditary glomerulopathy due to pathogenic variants in COL4A3 , COL4A4 , and COL4A5. Treatment with Renin-Angiotensin-Aldosterone System (RAAS) inhibitors can delay progression to end stage renal disease (ESRD). From 2018 until today, we performed Whole Exome Sequencing (WES) in 19 patients with AS phenotype with or without positive family history. Fourteen of these patients were children. Genetic testing was extended to family members at risk. All patients received a genetic diagnosis of AS: five X-linked AS (XLAS) males, five X-linked AS (XLAS) females, six autosomal dominant AS (ADAS), and one autosomal recessive AS (ARAS). After cascade screening four XLAS males and eight XLAS females, six ADAS and three ARAS heterozygotes were added to our initial results. Fifteen patients were eligible to start treatment with RAAS inhibitors after their diagnosis. All XLAS female patients, ARAS heterozygotes, and ADAS have been advised to be followed up, so that therapeutic intervention can begin in the presence of microalbuminuria. Genetic diagnosis of AS ensures early therapeutic intervention and appropriate follow up to delay progression to chronic kidney disease, especially in thet pediatric population.

Purpose: IGSF1 deficiency syndrome (immunoglobulin superfamily member 1) is considered the most common sex-linked cause of secondary congenital hypothyroidism and is characterized by a wide variety of other clinical and biochemical features, including hypoprolactinemia, transient and partial growth hormone deficiency, early/normal timing of testicular enlargement but delayed testosterone rise in puberty, and adult macro-orchidism. Congenital central hypothyroidism is a rare disease (1:65,000 births); the detection of which may be delayed and missed by neonatal screening programs since most neonatal screening programs are based on TSH determination in dried blood spots only. Untreated hypothyroidism may cause abnormal liver biochemistry and non-alcoholic fatty liver disease. Our aim is to report a case of secondary hypothyroidism in an infant with an uncommon initial presentation., Case Presentation (methods/results): A 3-month-old male baby was referred to our hospital due to elevated alpha-fetoprotein levels, hypercholesterolemia, and macrosomia. Initial investigations revealed enlarged fatty liver and central hypothyroidism. Pituitary insufficiency was biochemically excluded and a pituitary MRI showed normal findings. Upon genetic analysis, a hemizygous variant NM_001170961.1:c.2422dup, p.(His808Profs*14), in IGSF1 gene was detected, establishing the diagnosis of the IGSF1 deficiency syndrome. In our patient, no other clinical findings were identified. Treatment with levothyroxine led to the remission of liver disease., Conclusion: Liver disease may be the initial presentation of secondary hypothyroidism in neonates and infants. Macrosomia in patients with isolated secondary central hypothyroidism is a strong indicator of IGSF1 syndrome., (© 2023. The Author(s), under exclusive licence to Hellenic Endocrine Society.)

Whole-Exome Sequencing (WES) has proven valuable in the characterization of underlying genetic defects in most rare diseases (RDs). Copy Number Variants (CNVs) were initially thought to escape detection. Recent technological advances enabled CNV calling from WES data with the use of accurate and highly sensitive bioinformatic tools. Amongst 920 patients referred for WES, 454 unresolved cases were further analysed using the ExomeDepth algorithm. CNVs were called, evaluated and categorized according to ACMG/ClinGen recommendations. Causative CNVs were identified in 40 patients, increasing the diagnostic yield of WES from 50.7% (466/920) to 55% (506/920). Twenty-two CNVs were available for validation and were all confirmed; of these, five were novel. Implementation of the ExomeDepth tool promoted effective identification of phenotype-relevant and/or novel CNVs. Among the advantages of calling CNVs from WES data, characterization of complex genotypes comprising both CNVs and SNVs minimizes cost and time to final diagnosis, while allowing differentiation between true or false homozygosity, as well as compound heterozygosity of variants in AR genes. The use of a specific algorithm for calling CNVs from WES data enables ancillary detection of different types of causative genetic variants, making WES a critical first-tier diagnostic test for patients with RDs., Competing Interests: The authors declare no conflict of interest.

Background: Persistent hyperCKemia results from muscle dysfunction often attributed to genetic alterations of muscle-related genes, such as the dystrophin gene (DMD) . Retrospective assessment of findings from DMD analysis, in association with persistent HyperCKemia, was conducted., Patients and Methods: Evaluation of medical records from 1354 unrelated cases referred during the period 1996-2021. Assessment of data concerning the detection of DMD gene rearrangements and nucleotide variants., Results: A total of 730 individuals (657 cases, 569 of Greek and 88 of Albanian origins) were identified, allowing an overall estimation of dystrophinopathy incidence at ~1:3800 live male births. The heterogeneous spectrum of 275 distinct DMD alterations comprised exon(s) deletions/duplications, nucleotide variants, and rare events, such as chromosome translocation {t(X;20)}, contiguous gene deletions, and a fused gene involving the DMD and the DOCK8 genes. Ethnic-specific findings include a common founder variant in exon 36 ('Hellenic' variant)., Conclusions: Some 50% of hyperCKemia cases were characterized as dystrophinopathies, highlighting that DMD variants may be considered the most common cause of hyperCKemia in Greece. Delineation of the broad genetic and clinical heterogeneity is fundamental for actionable public health decisions and theragnosis, as well as the establishment of guidelines addressing ethical considerations, especially related to the mild asymptomatic patient subgroup.

Introduction: Non-syndromic polydactyly has been associated with pathogenic variants in 11 genes until today, including IQCE gene. More precisely, loss-of-function of IQCE is associated with the autosomal recessive disorder postaxial polydactyly type A7 (PAPA7, MIM #617642)., Case Presentation: A 3-year-old female patient was referred to our genetics department with postaxial polydactyly, syndactyly, brachydactyly, and hypoplastic teeth. Through whole-exome sequencing (WES), a pathogenic IQCE variant was identified (c.895_904del) in the homozygous state, which adequately explained the disease phenotype of our patient. However, copy number variant (CNV) analysis from WES data, using ExomeDepth, revealed a novel, likely pathogenic large deletion involving IQCE genomic regions (DEL:chr7:2606751_2641098) encompassing exons 2-18 of the gene., Conclusion: IQCE gene codes for a 695-amino acid protein located at the base of the primary cilia that positively regulates the Hedgehog signaling pathway. This case report represents the first description of a large deletion in IQCE and indicates that implementation of ExomeDepth in routine WES analysis can contribute valuable information toward elucidating the correct etiology of rare genetic diseases, increasing the diagnostic yield, and minimizing the need for additional tests., Competing Interests: The authors declare no conflict of interest., (Copyright © 2023 by S. Karger AG, Basel.)

Objectives: Genetics of epilepsy are highly heterogeneous and complex. Lesions detected involve genes encoding various types of channels, transcription factors, and other proteins implicated in numerous cellular processes, such as synaptogenesis. Consequently, a wide spectrum of clinical presentations and overlapping phenotypes hinders differential diagnosis and highlights the need for molecular investigations toward delineation of underlying mechanisms and final diagnosis. Characterization of defects may also contribute valuable data on genetic landscapes and networks implicated in epileptogenesis., Methods: This study reports on genetic findings from exome sequencing (ES) data of 107 patients with variable types of seizures, with or without additional symptoms, in the context of neurodevelopmental disorders., Results: Multidisciplinary evaluation of ES, including ancillary detection of copy number variants (CNVs) with the ExomeDepth tool, supported a definite diagnosis in 59.8% of the patients, reflecting one of the highest diagnostic yields in epilepsy., Conclusion: Emerging advances of next-generation technologies and ' in silico ' analysis tools offer the possibility to simultaneously detect several types of variations. Wide assessment of variable findings, specifically those found to be novel and least expected, reflects the ever-evolving genetic landscape of seizure development, potentially beneficial for increased opportunities for trial recruitment and enrollment, and optimized, even personalized, medical management.

ATP6V1B2 pathogenic variants are linked with variable phenotypes, such as dominant deafness-onychodystrophy syndrome (DDOD), autosomal dominant Zimmermann-Laband syndrome type 2 (ZLS2), and some cases of DOORS (deafness, onychodystrophy, osteodystrophy, intellectual disability [ID], and seizures). Epilepsy was first linked to ATP6V1B2, when the p.(Glu374Gln) missense variant was detected in a patient with ID and seizures, but without characteristic features of DDOD or ZLS2 syndromes. We herein report a novel pathogenic ATP6V1B2:p.Glu374Gly variant detected in an adult patient with ID and myoclonic-atonic seizures. The (re)occurrence of different variants affecting the same highly conserved hydrophilic glutamic acid on position 374 of the V-proton ATPase subunit B, indicates a potential novel pathogenic hotspot and a critical role for the specific residue in the development of epilepsy. ATP6V1B2 gene defects should be considered when analyzing patients with epilepsy, even in the absence of most cardinal features of DDOD, DOORS, or ZLS such as deafness, onychodystrophy, and osteodystrophy., (© 2022 Wiley Periodicals LLC.)

About 6000 to 7000 different rare disorders with suspected genetic etiologies have been described and almost 4500 causative gene(s) have been identified. The advent of next-generation sequencing (NGS) technologies has revolutionized genomic research and diagnostics, representing a major advance in the identification of pathogenic genetic variations. This study presents a 3-year experience from an academic genetics center, where 400 patients were referred for genetic analysis of disorders with unknown etiology. A phenotype-driven proband-only exome sequencing (ES) strategy was applied for the investigation of rare disorders, in the context of optimizing ES diagnostic yield and minimizing costs and time to definitive diagnosis. Overall molecular diagnostic yield reached 53% and characterized 243 pathogenic variants in 210 cases, 85 of which were novel and 148 known, contributing information to the community of disease and variant databases. ES provides an opportunity to resolve the genetic etiology of disorders and support appropriate medical management and genetic counseling. In cases with complex phenotypes, the identification of complex genotypes may contribute to more comprehensive clinical management. In the context of effective multidisciplinary collaboration between clinicians and laboratories, ES provides an efficient and appropriate tool for first-tier genomic analysis., (© 2021 Wiley Periodicals LLC.)