De Novo Variants in the ATPase Module of MORC2 Cause a Neurodevelopmental Disorder with Growth Retardation and Variable Craniofacial Dysmorphism.

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.

New developmental syndromes: Understanding the family experience.

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.