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Rubinstein-Taybi syndrome (RSTS) is an autosomal dominant disorder, caused by loss-of-function variants in CREBBP or EP300. Affected individuals present with distinctive craniofacial features, broad thumbs and/or halluces, and intellectual disability. RSTS phenotype has been well characterized in individuals of European descent but not in other populations. In this study, individuals from diverse populations with RSTS were assessed by clinical examination and facial analysis technology. Clinical data of 38 individuals from 14 different countries were analyzed. The median age was 7 years (age range: 7 months to 47 years), and 63% were females. The most common phenotypic features in all population groups included broad thumbs and/or halluces in 97%, convex nasal ridge in 94%, and arched eyebrows in 92%. Face images of 87 individuals with RSTS (age range: 2 months to 47 years) were collected for evaluation using facial analysis technology. We compared images from 82 individuals with RSTS against 82 age- and sex-matched controls and obtained an area under the receiver operating characteristic curve (AUC) of 0.99 (p < .001), demonstrating excellent discrimination efficacy. The discrimination was, however, poor in the African group (AUC: 0.79; p = .145). Individuals with EP300 variants were more effectively discriminated (AUC: 0.95) compared with those with CREBBP variants (AUC: 0.93). This study shows that clinical examination combined with facial analysis technology may enable earlier and improved diagnosis of RSTS in diverse populations., (© 2020 Wiley Periodicals LLC.)

Background: We report here clinical, cytogenetic and molecular data for a pair of monochorionic diamniotic twins with paternal isodisomy for chromosome 19. Both twins presented with dysmorphic features and global developmental delay. This represents, to our knowledge, the first individual human case of paternal uniparental disomy for chromosome 19 (UPD19)., Methods: Whole-exome sequencing, together with conventional karyotype and SNP array analysis were performed along with genome-wide DNA methylation array for delineation of the underlying molecular defects., Results: Conventional karyotyping on amniocytes and lymphocytes showed normal karyotypes for both twins. Whole-exome sequencing did not identify any pathogenic sequence variants but >5000 homozygous exonic variants on chromosome 19, suggestive of UPD19. SNP arrays on blood and buccal DNA both showed paternal isodisomy for chromosome 19. Losses of imprinting for known imprinted genes on chromosome 19 were identified, including ZNF331 , PEG3 , ZIM2 and MIMT1. In addition, imprinting defects were also identified in genes located on other chromosomes, including GPR1-AS , JAKMP1 and NHP2L1 ., Conclusion: Imprinting defects are the most likely cause for the dysmorphism and developmental delay in this first report of monozygotic twins with UPD19. However, epigenotype-phenotype correlation will require identification of additional individuals with UPD19 and further molecular analysis., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2018. No commercial re-use. See rights and permissions. Published by BMJ.)