Sudden death and aborted sudden death have been observed in patients with biallelic variants in TECRL. However, phenotypes have only begun to be described and no data are available on medical therapy after long-term follow-up. An international, multi-centre retrospective review was conducted. We report new cases associated with TECRL variants and long-term follow-up from previously published cases. We present 10 cases and 37 asymptomatic heterozygous carriers. Median age at onset of cardiac symptoms was 8 years (range 1–22 years) and cases were followed for an average of 10.3 years (standard deviation 8.3), right censored by death in three cases. All patients on metoprolol, bisoprolol, or atenolol were transitioned to nadolol or propranolol due to failure of therapy. Phenotypes typical of both long QT syndrome and catecholaminergic polymorphic ventricular tachycardia (CPVT) were observed. We also observed divergent phenotypes in some cases despite identical homozygous variants. None of 37 heterozygous family members had a cardiac phenotype. Patients with biallelic pathogenic TECRL variants present with variable cardiac arrhythmia phenotypes, including those typical of long QT syndrome and CPVT. Nadolol and propranolol may be superior beta-blockers in this setting. No cardiac disease or sudden death was present in patients with a heterozygous genotype.
The diagnostic yield of genetic testing for ocular/oculocutaneous albinism (OA/OCA) in a diverse pediatric population in the United States (U.S.) is unclear. Phenotypes of 53 patients who presented between 2006–2022 with OA/OCA were retrospectively correlated with genetic testing results. Genetic diagnostic yield was defined as detection of pathogenic/likely pathogenic variant(s) matching the anticipated inheritance for that gene–disease relationship. Variant reclassifications of those with variants of uncertain significance (VUS) and without positive diagnostic yield were completed. Overall initial genetic diagnostic yield of OA/OCA was 66%. There was no significant difference (p = 0.59) between race and ethnicities (Black (78%), White (59%), Hispanic/Latino (64%)); however, the diagnostic yield of OA (33%) was significantly lower (p = 0.007) than OCA (76%). Causative variants in OCA2 (28%) and TYR (20%) were most common. Further, Hermansky–Pudlak syndrome variants were identified in 9% of patients. Re-classification of VUS in non-diagnostic cases resulted in genetic diagnoses for 29% of individuals and increased overall diagnostic yield to 70% of all subjects. There is a high diagnostic yield of genetic testing of patients overall with OA/OCA in a diverse U.S. based pediatric population. Presence or absence of cutaneous involvement of albinism significantly affects genetic diagnostic yield.
The aim of this study was to evaluate the diagnostic yield from prior genetic testing in a 20-year cohort of pediatric patients with congenital cataracts. A retrospective review of patients with congenital cataracts who underwent genetic testing was completed from 2003–2022. The diagnostic yield of the test was determined by variant classification and inheritance pattern. Variants from initial testing underwent reclassification in accordance with ACMG-AMP (American College of Medical Genetics and Genomics—American Association of Molecular Pathology) 2015 or 2020 ACMG CNV guidelines. A total of 95 variants were identified in 52 patients with congenital cataracts (42 bilateral, 10 unilateral); 42 % were White, 37% were Hispanic, 8% were Black, and 6% were Asian. The majority of patients (92%) did not have a family history of congenital cataracts but did have systemic illnesses (77%). Whole exome sequencing and targeted congenital cataract panels showed diagnostic yields of 46.2% and 37.5%, respectively. Microarray had the lowest yield at 11%. Compared to the initial classification, 16% (15 of 92 variants) had discrepant reclassifications. More testing is needed, and an increased focus is warranted in the field of ocular genetics on congenital cataracts, particularly in those with systemic illnesses and no family history, to advance our knowledge of this potentially blinding condition.
19 July 2022 in The Journal of Molecular Diagnostics
In 2019, the American College of Medical Genetics and Genomics and the Clinical Genome Resource published updated technical standards for the interpretation and reporting of copy number variants (CNVs), introducing a semiquantitative classification system to improve standardization and consistency between laboratories. Evaluation of these guidelines' performance will inform laboratories about the impact of their implementation into clinical practice. A total of 145 difficult-to-classify CNVs, originally assessed by an academic molecular diagnostic laboratory, were re-interpreted/classified according to the American College of Medical Genetics and Genomics-Clinical Genome Resource guidelines. Classifications between interpretation systems were then compared. The concordance rate was 60.7%, and significantly more variants of uncertain significance were obtained when using the guidelines (n = 98) versus the laboratory's classification system (n = 49; P < 0.001). The concordance rate was presumably impacted by the intentionally unclear nature of the selected variants. The difference in variant of uncertain significance rate was largely due to laboratory-specific practices for variant interpretation and reporting and differences in utilization of general population data. Laboratory-specific policies and practices may need to be addressed for true standardization. Challenges to consistent guideline utilization are centered around the general lack of high-quality curated data available for CNV interpretations and the inherent subjectivity in the selection of evidence criteria and application of evidence points. Multiple aspects of the guidelines were highlighted to further improve classification standardization.
10 April 2024 in American Journal of Medical Genetics Part A
CHARGE syndrome is a rare multi‐system condition associated with CHD7 variants. However, ocular manifestations and particularly ophthalmic genotype–phenotype associations, are not well‐studied. This study evaluated ocular manifestations and genotype–phenotype associations in pediatric patients with CHARGE syndrome. A retrospective chart review included pediatric patients under 20 years‐old with clinical diagnosis of CHARGE syndrome and documented ophthalmic examination. Demographics, genetic testing, and ocular findings were collected. Comprehensive literature review enhanced the genotype–phenotype analysis. Forty‐two patients (20 male) underwent eye examination at an average age of 9.45 ± 6.52 years‐old. Thirty‐nine (93%) had ophthalmic manifestations in at least one eye. Optic nerve/chorioretinal colobomas were most common (38 patients), followed by microphthalmia (13), cataract (6), and iris colobomas (4). Extraocular findings included strabismus (32 patients), nasolacrimal duct obstructions (11, 5 with punctal agenesis), and cranial nerve VII palsy (10). Genotype–phenotype analyses (27 patients) showed variability in ocular phenotypes without association to location or variant types. Splicing (10 patients) and frameshift (10) variants were most prevalent. Patients with CHARGE syndrome may present with a myriad of ophthalmic manifestations. There is limited data regarding genotype–phenotype correlations and additional studies are needed.
1 May 2021 in The Journal of Molecular Diagnostics
Diagnostic laboratories gather phenotypic data through requisition forms, but there is no consensus as to which data are essential for variant interpretation. The ClinGen Cardiomyopathy Variant Curation Expert Panel defined a phenotypic data set for hypertrophic cardiomyopathy (HCM) variant interpretation, with the goal of standardizing requisition forms. Phenotypic data elements listed on requisition forms from nine leading cardiomyopathy testing laboratories were compiled to assess divergence in data collection. A pilot of 50 HCM cases was implemented to determine the feasibility of harmonizing data collection. Laboratory directors were surveyed to gauge potential for adoption of a minimal data set. Wide divergence was observed in the phenotypic data fields in requisition forms. The 50-case pilot showed that although demographics and assertion of a clinical diagnosis of HCM had 86% to 98% completion, specific phenotypic features, such as degree of left ventricular hypertrophy, ejection fraction, and suspected syndromic disease, were completed only 24% to 44% of the time. Nine data elements were deemed essential for variant classification by the expert panel. Participating laboratories unanimously expressed a willingness to adopt these data elements in their requisition forms. This study demonstrates the value of comparing and sharing best practices through an expert group, such as the ClinGen Program, to enhance variant interpretation, providing a foundation for leveraging cumulative case-level data in public databases and ultimately improving patient care.