MORC2 encodes an ATPase that plays a role in chromatin remodeling, DNA repair, and transcriptional regulation. Heterozygous variants in MORC2 have been reported in individuals with autosomal-dominant Charcot-Marie-Tooth disease type 2Z and spinal muscular atrophy, and the onset of symptoms ranges from infancy to the second decade of life. Here, we present a cohort of 20 individuals referred for exome sequencing who harbor pathogenic variants in the ATPase module of MORC2. Individuals presented with a similar phenotype consisting of developmental delay, intellectual disability, growth retardation, microcephaly, and variable craniofacial dysmorphism. Weakness, hyporeflexia, and electrophysiologic abnormalities suggestive of neuropathy were frequently observed but were not the predominant feature. Five of 18 individuals for whom brain imaging was available had lesions reminiscent of those observed in Leigh syndrome, and five of six individuals who had dilated eye exams had retinal pigmentary abnormalities. Functional assays revealed that these MORC2 variants result in hyperactivation of epigenetic silencing by the HUSH complex, supporting their pathogenicity. The described set of morphological, growth, developmental, and neurological findings and medical concerns expands the spectrum of genetic disorders resulting from pathogenic variants in MORC2.Microrchidia CW-type zinc finger protein 2 (MORC2, MIM: 616661) is a member of a family of ATPases fundamental for epigenetic silencing through chromatin modification. [1][2][3] It has most commonly been associated with autosomal-dominant Charcot-Marie-Tooth (CMT) disease type 2Z (MIM: 616688), a form of axonal neuropathy with progressive weakness, muscle cramps, and sensory impair-ment presenting in childhood or early adulthood. [4][5][6][7] However, some reported individuals presented with hypotonia, generalized muscle weakness, and delayed milestones, 4 or occasionally with spinal muscular atrophy, intellectual disability, hearing loss, pyramidal signs, microcephaly, and brain atrophy, in infancy. 4,5,[8][9][10] The association of MORC2 variants with human disease has only recently

Von Hippel‐Lindau disease (VHL) is a heritable condition caused by pathogenic variants in VHL and is characterized by benign and malignant lesions in the central nervous system (CNS) and abdominal viscera. Due to its variable expressivity, existing efforts to collate VHL patient data do not adequately capture all VHL manifestations. We developed a comprehensive and standardized VHL database in the web‐based application, REDCap, that thoroughly captures all VHL manifestation data. As an initial trial, information from 86 VHL patients from the University Health Network/Hospital for Sick Children was populated into the database. Analysis of this cohort showed missense variants occurring with the greatest frequency, with all variants localizing to the α‐ or β‐domains of VHL. The most prevalent manifestations were central nervous system (CNS), renal, and retinal neoplasms, which were associated with frameshift variants and large deletions. We observed greater age‐related penetrance for CNS hemangioblastomas with truncating variants compared to missense, while the reverse was true for pheochromocytomas. We demonstrate the utility of a comprehensive VHL database, which supports the standardized collection of clinical and genetic data specific to this patient population. Importantly, we expect that its web‐based design will facilitate broader international collaboration and lead to a better understanding of VHL.

We conducted integrative somatic–germline analyses by deeply sequencing 864 cancer-associated genes, complete genomes and transcriptomes for 300 mostly previously treated children and adolescents/young adults with cancer of poor prognosis or with rare tumors enrolled in the SickKids Cancer Sequencing (KiCS) program. Clinically actionable variants were identified in 56% of patients. Improved diagnostic accuracy led to modified management in a subset. Therapeutically targetable variants (54% of patients) were of unanticipated timing and type, with over 20% derived from the germline. Corroborating mutational signatures (SBS3/BRCAness) in patients with germline homologous recombination defects demonstrates the potential utility of PARP inhibitors. Mutational burden was significantly elevated in 9% of patients. Sequential sampling identified changes in therapeutically targetable drivers in over one-third of patients, suggesting benefit from rebiopsy for genomic analysis at the time of relapse. Comprehensive cancer genomic profiling is useful at multiple points in the care trajectory for children and adolescents/young adults with cancer, supporting its integration into early clinical management.

Increased application of next generation sequencing has led to the discovery of a multitude of new neurodevelopmental syndromes, contributing to an increased diagnostic rate for exome sequencing from 25% originally to 40% currently. Owing to the recent recognition of these syndromes, as well as the types of large‐scale studies (with limited phenotype information) often making these discoveries, these disorders may be poorly characterized clinically. As a result there is very limited information and disorder‐specific support available to patients and families. We used a qualitative approach to explore how families experience a diagnosis of a new syndrome. We conducted semi‐structured telephone interviews with parents and adult siblings of children who received a diagnosis of a new syndrome after whole exome sequencing (WES) performed through a translational research study. The interviews were recorded, transcribed verbatim, and transcripts were analyzed using grounded theory methods. Analysis of the 12 interviews revealed that a lack of information about the child's condition continues to play a large role in these families' experiences even after diagnosis. Almost all (92%) participants expressed ongoing uncertainty about their child's health and future. Most (83%) participants were interested in identifying other families with the same syndrome, which was related to both social support and seeking of information. Interestingly, 33% of participants worried about the child's risk for cancer due to their syndrome. Our results highlight some of the needs of families of children with new syndromes, and emphasize important issues care providers should address in pre‐ and post‐test genetic counseling for WES and whole genome sequencing.