Secondary ACMG and non-ACMG genetic findings in a multiethnic cohort of 16,713 pediatric participants.

PURPOSE: Clinical next-generation sequencing is an effective approach for identifying pathogenic sequence variants that are medically actionable for participants and families but are not associated with the participant's primary diagnosis. These variants are called secondary findings (SFs). According to the literature, there is no report of the types and frequencies of SFs in a large pediatric cohort which includes substantial African-American participants. We sought to investigate the types (including American College of Medical Genetics and Genomics [ACMG] and non-ACMG recommended gene lists), frequencies, and rates of SFs, as well as the effects of SF disclosure on the participants and families of a large pediatric cohort at the Center for Applied Genomics at The Children's Hospital of Philadelphia (CHOP). METHODS: We systematically identified pathogenic (P) and likely pathogenic (LP) variants in established disease-causing genes, adhering to ACMG v3.2 secondary finding guidelines and beyond. For non-ACMG secondary findings, akin to incidental findings in clinical settings, we utilized a set of criteria focusing on pediatric onset, high penetrance, moderate to severe phenotypes, and the clinical actionability of the variants. This criteria-based approach was applied rather than using a fixed gene list to ensure that the variants identified are likely to impact participant health significantly. To identify and categorize these variants, we employed a clinical-grade variant classification standard per ACMG/AMP recommendations; additionally, we conducted a detailed literature search to ensure a comprehensive exploration of potential secondary findings relevant to pediatric participants. RESULTS: We report a distinctive distribution of 1,464 P/LP SF variants in 16,713 participants. There were 427 unique variants in ACMG genes and 265 in non-ACMG genes. The most frequently mutated genes among the ACMG and non-ACMG gene lists were TTR (41.6%) and CHEK2 (7.16%), respectively. Overall, variants of possible medical importance were found in 8.76% of participants in both ACMG (5.81%) and non-ACMG (2.95%) genes.

Novel insights into the phenotypic spectrum and pathogenesis of Hardikar syndrome.

PURPOSE: Hardikar syndrome (HS, MIM #301068) is a female-specific multiple congenital anomaly syndrome characterized by retinopathy, orofacial clefting, aortic coarctation, biliary dysgenesis, genitourinary malformations, and intestinal malrotation. We previously showed that heterozygous nonsense and frameshift variants in MED12 cause HS. The phenotypic spectrum of disease and the mechanism by which MED12 variants cause disease is unknown. We aim to expand the phenotypic and molecular landscape of HS and elucidate the mechanism by which MED12 variants cause disease. METHODS: We assembled and clinically and molecularly characterized a cohort of 11 previously-unreported individuals with HS. We additionally studied the effect of MED12 deficiency on ciliary biology and hedgehog and YAP signaling, pathways implicated in diseases with phenotypic overlap with HS. RESULTS: We report novel phenotypes associated with HS, including cardiomyopathy, arrhythmia, and vascular anomalies and expand the molecular landscape of HS to include splice site variants. We additionally demonstrate that MED12 deficiency causes decreased cell ciliation and impairs hedgehog and YAP signaling. CONCLUSION: Our data support updating HS standard-of-care to include regular cardiac imaging, arrhythmia screening, and vascular imaging. We further propose that dysregulation of ciliogenesis and YAP and hedgehog signaling contributes to the pathogenesis of HS.

Punctal Atresia As a Clinical Indicator of Systemic Genetic Anomalies.

BACKGROUND: Punctal atresia or agenesis (PA) is a rare congenital anomaly characterized by the absence or closure of the tear duct puncta, potentially linked to systemic genetic anomalies. The necessity of a genetic workup based solely on the presence of PA remains uncertain. This study investigates a cohort of PA patients, examining the prevalence and types of associated syndromes. METHODS: A retrospective medical records review of all patients diagnosed with PA at the Children's Hospital of Philadelphia between 2009-2023 was conducted, analyzing medical histories and genetic testing results. Primary outcomes included the prevalence of systemic syndromes, while secondary outcomes focused on the variety of associated syndromes. RESULTS: Forty-four patients were included, of which 31 were male (70%) with a mean ± SD age 3.3 ± 3.3 years. Overall, 87 puncta in the study cohort were affected, and 26 cases (59%) were bilateral. Systemic abnormalities or genetic syndromes were identified in 19 patients (43%), with the most common being Ectodermal Dysplasia and Down syndrome. Additional rare syndromes were demonstrated. No significant association was found between systemic abnormalities and gender, bilaterality, or the number of puncta involved. CONCLUSIONS: A high incidence of systemic syndromes (43%) was observed in the study cohort. In individuals with PA who also exhibit extraocular disease, systemic evaluation and genetic workup should be considered. Syndromic diagnoses identified in our cohort also include: Branchio-oto-renal syndrome, 22q11.2 deletion syndrome, 1q21.1 microdeletion syndrome, NF1, monosomy 4q and trisomy 6q, which represent novel associations. The lack of correlation between PA's phenotypic severity and systemic abnormalities highlights the need to obtain a comprehensive medical history and consider a systemic workup in PA patients.

An Adolescent Boy With Hypoxia, Microscopic Hematuria, and Hypertension.

A 13-year-old boy presented with hypoxia, microscopic hematuria, and elevated blood pressures. Persistent microscopic hematuria and hypertension led to investigation of glomerular and non-glomerular causes of hematuria. After reviewing his clinical course, family history, and laboratory testing, an additional test was sent, revealing the diagnosis.

Burden re-analysis of neurodevelopmental disorder cohorts for prioritization of candidate genes.

This study aimed to uncover novel genes associated with neurodevelopmental disorders (NDD) by leveraging recent large-scale de novo burden analysis studies to enhance a virtual gene panel used in a diagnostic setting. We re-analyzed historical trio-exome sequencing data from 745 individuals with NDD according to the most recent diagnostic standards, resulting in a cohort of 567 unsolved individuals. Next, we designed a virtual gene panel containing candidate genes from three large de novo burden analysis studies in NDD and prioritized candidate genes by stringent filtering for ultra-rare de novo variants with high pathogenicity scores. Our analysis revealed an increased burden of de novo variants in our selected candidate genes within the unsolved NDD cohort and identified qualifying de novo variants in seven candidate genes: RIF1, CAMK2D, RAB11FIP4, AGO3, PCBP2, LEO1, and VCP. Clinical data were collected from six new individuals with de novo or inherited LEO1 variants and three new individuals with de novo PCBP2 variants. Our findings add additional evidence for LEO1 as a risk gene for autism and intellectual disability. Furthermore, we prioritize PCBP2 as a candidate gene for NDD associated with motor and language delay. In summary, by leveraging de novo burden analysis studies, employing a stringent variant filtering pipeline, and engaging in targeted patient recruitment, our study contributes to the identification of novel genes implicated in NDDs.