Integrated genome and transcriptome sequencing identifies a noncoding mutation in the genome replication factor DONSON as the cause of microcephaly-micromelia syndrome.

While next-generation sequencing has accelerated the discovery of human disease genes, progress has been largely limited to the "low hanging fruit" of mutations with obvious exonic coding or canonical splice site impact. In contrast, the lack of high-throughput, unbiased approaches for functional assessment of most noncoding variants has bottlenecked gene discovery. We report the integration of transcriptome sequencing (RNA-seq), which surveys all mRNAs to reveal functional impacts of variants at the transcription level, into the gene discovery framework for a unique human disease, microcephaly-micromelia syndrome (MMS). MMS is an autosomal recessive condition described thus far in only a single First Nations population and causes intrauterine growth restriction, severe microcephaly, craniofacial anomalies, skeletal dysplasia, and neonatal lethality. Linkage analysis of affected families, including a very large pedigree, identified a single locus on Chromosome 21 linked to the disease (LOD > 9). Comprehensive genome sequencing did not reveal any pathogenic coding or canonical splicing mutations within the linkage region but identified several nonconserved noncoding variants. RNA-seq analysis detected aberrant splicing in DONSON due to one of these noncoding variants, showing a causative role for DONSON disruption in MMS. We show that DONSON is expressed in progenitor cells of embryonic human brain and other proliferating tissues, is co-expressed with components of the DNA replication machinery, and that Donson is essential for early embryonic development in mice as well, suggesting an essential conserved role for DONSON in the cell cycle. Our results demonstrate the utility of integrating transcriptomics into the study of human genetic disease when DNA sequencing alone is not sufficient to reveal the underlying pathogenic mutation.

The differential diagnosis of spastic diplegia.

Spastic diplegia is the most common form of cerebral palsy worldwide. Many disorders mimic spastic diplegia, which can result in misdiagnosis for the child with resultant negative treatment and family counselling implications. In this paper, the authors provide a brief review of spastic diplegia and the various disorders in the differential diagnosis. We also provide a diagnostic algorithm to assist physicians in making the correct diagnosis.

The registry and follow-up of complex pediatric therapies program of Western Canada: a mechanism for service, audit, and research after life-saving therapies for young children.

Newly emerging health technologies are being developed to care for children with complex cardiac defects. Neurodevelopmental and childhood school-related outcomes are of great interest to parents of children receiving this care, care providers, and healthcare administrators. Since the 1970s, neonatal follow-up clinics have provided service, audit, and research for preterm infants as care for these at-risk children evolved. We have chosen to present for this issue the mechanism for longitudinal follow-up of survivors that we have developed for western Canada patterned after neonatal follow-up. Our program provides registration for young children receiving complex cardiac surgery, heart transplantation, ventricular assist device support, and extracorporeal life support among others. The program includes multidisciplinary assessments with appropriate neurodevelopmental intervention, active quality improvement evaluations, and outcomes research. Through this mechanism, consistently high (96%) follow-up over two years is maintained.

Two-year general and neurodevelopmental outcome after neonatal complex cardiac surgery in patients with deletion 22q11.2: a comparative study.

OBJECTIVE: Neonatal complex cardiac surgery carries a significant risk for adverse neurodevelopmental outcome. We hypothesized this risk to be higher in patients with deletion 22q11.2. METHODS: From 1996 to 2004, neonates who had complex cardiac surgery at age 6 weeks or less had multisite, multidisciplinary health and neurodevelopmental outcomes (Bayley Scales of Infant Development II; mental and psychomotor developmental indices [MDI, PDI] as mean [SD] and delay [<70]) assessed at 18 to 24 months of age. All 16 patients with deletion 22q11.2 (group 1) were compared with 16 patients without deletion 22q11.2 (group 2) having undergone neonatal complex cardiac surgery at the same center and matched for cardiac lesion, socioeconomic status, and year of operation. Outcomes were compared by univariate and multivariate analyses. RESULTS: Heart lesions in each group consisted of 6 (37.5%) cases of interrupted aortic arch, 6 (37.5%) cases of truncus arteriosus, and 4 (25%) cases of tetralogy of Fallot. Outcomes were available for all survivors. Mortality was 3 (19%) and 1 (6%) in groups 1 and 2, respectively (P = .6). MDI and PDI scores were 66.1 (10.6) and 55.0 (9.4) for group 1 and 86.3 (14.6) and 82.3 (14.3) for group 2 (P < .001). Only deletion 22q11.2 was significant in stepwise multiple regression to predict MDI and PDI scores. Mental delay occurred in 8 (61.5%) of 13 in group 1 and 2 (13.8%) of 15 in group 2 (P = .016). Psychomotor delay occurred in 11 (84.6%) of 13 in group 1 and 1 (6.7%) of 15 in group 2 (P < .001). CONCLUSION: Neonates affected by deletion 22q11.2 and having neonatal complex cardiac surgery have significantly worse neurodevelopmental outcome than do those without deletion 22q11.2.