Genomic analyses in Cornelia de Lange Syndrome and related diagnoses: Novel candidate genes, genotype-phenotype correlations and common mechanisms.

Cornelia de Lange Syndrome (CdLS) is a rare, dominantly inherited multisystem developmental disorder characterized by highly variable manifestations of growth and developmental delays, upper limb involvement, hypertrichosis, cardiac, gastrointestinal, craniofacial, and other systemic features. Pathogenic variants in genes encoding cohesin complex structural subunits and regulatory proteins (NIPBL, SMC1A, SMC3, HDAC8, and RAD21) are the major pathogenic contributors to CdLS. Heterozygous or hemizygous variants in the genes encoding these five proteins have been found to be contributory to CdLS, with variants in NIPBL accounting for the majority (>60%) of cases, and the only gene identified to date that results in the severe or classic form of CdLS when mutated. Pathogenic variants in cohesin genes other than NIPBL tend to result in a less severe phenotype. Causative variants in additional genes, such as ANKRD11, EP300, AFF4, TAF1, and BRD4, can cause a CdLS-like phenotype. The common role that these genes, and others, play as critical regulators of developmental transcriptional control has led to the conditions they cause being referred to as disorders of transcriptional regulation (or "DTRs"). Here, we report the results of a comprehensive molecular analysis in a cohort of 716 probands with typical and atypical CdLS in order to delineate the genetic contribution of causative variants in cohesin complex genes as well as novel candidate genes, genotype-phenotype correlations, and the utility of genome sequencing in understanding the mutational landscape in this population.

Education format and resource preferences among registrants of a pediatric-focused CME website.

BACKGROUND: Despite dramatic increase in Internet-based CME activities, little is known about physician Internet CME preferences. AIMS: To identify the education format and resource preferences among registrants of a pediatric-focused CME website. METHODS: Preferences of physician registrants at PedsEducation.org between July 2000-November 2007 (n = 1388) were assessed via survey. A secondary analysis of respondent demographics vs. reported preferences was conducted. RESULTS: A total of 345 physicians participated (25% response rate). The majority (73%, n = 252) identified free CME as a highly important feature of an Internet CME resource; monthly case series was identified as the least important. Seventy-five percent of respondents (n = 260) identified practice guideline updates as a highly useful practice resource; practice feedback was identified as the least useful. Respondents with < or =10 years practice experience were more likely to identify case-based CME as highly useful to their daily practice (p < 0.001); respondents who spend > or = 90% working time on patient care were more likely to identify Internet CME as a highly useful CME format (p < 0.001). CONCLUSION: Internet CME preferences of PedsEducation.org registrants differ from those typically associated with knowledge gains and behavior changes. Demographic characteristics may influence these preferences.

Phenotypic variability in deficiency of the α subunit of succinate-CoA ligase.

Succinyl-CoA synthetase or succinate-CoA ligase deficiency can result from biallelic mutations in SUCLG1 gene that encodes for the alpha subunit of the succinyl-CoA synthetase. Mutations in this gene were initially associated with fatal infantile lactic acidosis. We describe an individual with a novel biallelic pathogenic mutation in SUCLG1 with a less severe phenotype dominated by behavioral problems. The mutation was identified to be c.512A>G corresponding to a p.Asn171Ser change in the protein. The liquid chromatography tandem mass spectrometry-based enzyme activity assay on cultured fibroblasts revealed a markedly reduced activity of succinyl-CoA synthetase enzyme when both ATP and GTP were substrates, affecting both ADP-forming and GDP-forming functions of the enzyme.

Mutations in the TGF-ß repressor SKI cause Shprintzen-Goldberg syndrome with aortic aneurysm.

Elevated transforming growth factor (TGF)-ß signaling has been implicated in the pathogenesis of syndromic presentations of aortic aneurysm, including Marfan syndrome (MFS) and Loeys-Dietz syndrome (LDS). However, the location and character of many of the causal mutations in LDS intuitively imply diminished TGF-ß signaling. Taken together, these data have engendered controversy regarding the specific role of TGF-ß in disease pathogenesis. Shprintzen-Goldberg syndrome (SGS) has considerable phenotypic overlap with MFS and LDS, including aortic aneurysm. We identified causative variation in ten individuals with SGS in the proto-oncogene SKI, a known repressor of TGF-ß activity. Cultured dermal fibroblasts from affected individuals showed enhanced activation of TGF-ß signaling cascades and higher expression of TGF-ß-responsive genes relative to control cells. Morpholino-induced silencing of SKI paralogs in zebrafish recapitulated abnormalities seen in humans with SGS. These data support the conclusions that increased TGF-ß signaling is the mechanism underlying SGS and that high signaling contributes to multiple syndromic presentations of aortic aneurysm.

Newborn screening: current status.

Newborn screening, which represents one of the major advances in child health of the past century, has been carried out in all fifty U.S. states since the 1970s. Newborn screening programs are state-run, and decisions are left to the individual states regarding the conditions to be screened for, the mechanism for confirmatory testing, follow-up care, and financing of the programs. Laboratory advances in tandem mass spectrometry make it possible to screen newborns for many rare inborn errors of metabolism. This raises many policy issues including screening's cost-effectiveness, ethics, quality, and oversight.

Galactosemia.

Despite the dramatic response of sick neonates with galactosemia to the withdrawal of galactose from the diet, over the long-term, complications, including learning disorders, verbal apraxia, and ataxia, often develop. It is clear that, although lifelong galactose restriction remains the basis of treatment for this disease, additional treatment methods are needed. The neurologist familiar with galactosemia can assist in diagnosis of neonates presenting with central nervous system symptoms. Familiarity with the long-term neurologic consequences of galactosemia can help the neurologist assist the family with prognostic information and to avoid unnecessary tests when complications occur.