The standard of care for first-tier clinical investigation of the aetiology of congenital malformations and neurodevelopmental disorders is chromosome microarray analysis (CMA) for copy-number variations (CNVs), often followed by gene(s)-specific sequencing searching for smaller insertion–deletions (indels) and single-nucleotide variant (SNV) mutations. Whole-genome sequencing (WGS) has the potential to capture all classes of genetic variation in one experiment; however, the diagnostic yield for mutation detection of WGS compared to CMA, and other tests, needs to be established. In a prospective study we utilised WGS and comprehensive medical annotation to assess 100 patients referred to a paediatric genetics service and compared the diagnostic yield versus standard genetic testing. WGS identified genetic variants meeting clinical diagnostic criteria in 34% of cases, representing a fourfold increase in diagnostic rate over CMA (8%; P value=1.42E−05) alone and more than twofold increase in CMA plus targeted gene sequencing (13%; P value=0.0009). WGS identified all rare clinically significant CNVs that were detected by CMA. In 26 patients, WGS revealed indel and missense mutations presenting in a dominant (63%) or a recessive (37%) manner. We found four subjects with mutations in at least two genes associated with distinct genetic disorders, including two cases harbouring a pathogenic CNV and SNV. When considering medically actionable secondary findings in addition to primary WGS findings, 38% of patients would benefit from genetic counselling. Clinical implementation of WGS as a primary test will provide a higher diagnostic yield than conventional genetic testing and potentially reduce the time required to reach a genetic diagnosis.

OBJECTIVE -We sought to determine the absolute risk of having a congenital anomaly in relation to periconceptional GHb concentration among women with prepregnancy diabetes.RESEARCH DESIGN AND METHODS -Two reviewers independently retrieved all cohort studies through a systematic literature search between January 1985 and May 2006. For each study, the absolute risk of having a pregnancy affected by a major or minor structural anomaly (diagnosed either antenatally or up to 28 days after conception) was calculated according to the number of SDs of GHb above the mean for nondiabetic, nonpregnant control subjects. A multilevel logistic-normal model was used to pool the data, which were expressed in tabular and graphic formats.RESULTS -In seven cohort studies, there were 117 anomalies among 1,977 pregnancies. At a periconceptional GHb concentration 0 SD above normal, the absolute risk of a pregnancy affected by a congenital anomaly was ϳ2% (95% CI 0.0 -4.4). At 2 SD above normal, the risk was 3% (0.4 -6.1), and at 8 SD it was ϳ10% (2.3-17.8). For each 1-SD unit increase in GHb, the associated risk of a congenital malformation increased by an odds ratio of 1.2 (95% CI 1.1-1.4). The risk in relation to A1C followed the same pattern.CONCLUSIONS -Using data from a limited number of published studies, a practical aid was developed to optimize use of the GHb and A1C concentrations for estimating the absolute risk of a congenital anomaly in the offspring of women with prepregnancy diabetes. Diabetes Care 30:1920-1925, 2007T he offspring of women with prepregnancy diabetes are at increased risk of having a structural congenital anomaly (1-3). It is hypothesized that hyperglycemia exerts a teratogenic effect on the developing fetus (4,5). There is a positive association between poor glycemic control in the periconcep-tion period and the risk of such anomalies (1,6 -10).Those who counsel women with prepregnancy diabetes currently lack a valid, standardized method to estimate of the risk of a fetal anomaly in relation to the periconceptional GHb concentration, a measure of glycemic control (10). We undertook a meta-analysis to determine the absolute risk of congenital anomalies in relation to periconceptional GHb. The abstract of each article was read and determined for eligibility according to the following criteria: 1) a cohort study comprising at least 20 women with prepregnancy diabetes; 2) GHb levels were measured in the periconception period, defined as the period from 17 weeks before conception up to the completion of the first trimester of pregnancy (i.e., up to 16 weeks' gestation); 3) the associated number of congenital malformations was provided at each category of GHb concentration; and 4) reference values for the GHb (i.e., assay mean and SD) were provided for a nondiabetic control population. Full-text articles deemed eligible were reviewed by A.G. and J.G.R. to ensure that they met the inclusion criteria. RESEARCH DESIGN AND METHODS Literature searchTwo investigators independently searched PubMed and Embase databas...

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

Jacobsen syndrome (JS) is a rare contiguous gene disorder characterized by a deletion within the distal part of the long arm of chromosome 11 ranging in size from 7 to 20 Mb. The clinical findings include characteristic dysmorphic features, growth and psychomotor delays and developmental anomalies involving the brain, eyes, heart, kidneys, immune, hematologic, endocrine, and gastrointestinal systems. The majority of cases are due to a terminal deletion of 11q; however interstitial deletions have also been reported. We report on a child with clinical manifestations consistent with JS who had a 2.899 Mb interstitial deletion at 11q24.2-q24.3 which is the smallest interstitial deletion reported so far to our knowledge. This deletion includes the KIRREL3 gene, and given our patient's history of neurocognitive delay and autism spectrum disorder, it raises the possibility that this gene is a candidate for the social and expressive language delay observed in our patient.