Exome Analysis in Clinical Practice: Expanding the Phenotype of Bartsocas-Papas Syndrome

摘要

Exome analysis has had a dramatic impact on genetic research. We present the application of such newly generated information to patient care. The patient was a female, born with normal growth parameters to nonconsanguineous parents after an uneventful pregnancy. She had bilateral cleft lip/palate and ankyloblepharon. Sparse hair, dysplastic nails and hypohidrosis were subsequently noted. With exception of speech related issues, her development was normal. A clinical diagnosis of ankyloblepharon-ectodermal defects-cleft lip/palate or Hay-Wells syndrome resulted in TP63 sequence analysis. TP63 sequence and deletion/duplication analysis of all coding exons had a normal result, as did chromosome and SNP array analysis. Diagnostic exome analysis revealed a heterozygous nonsense mutation in KRT83 categorized as deleterious and associated with monilethrix. In addition, a homozygous missense variant of unknown clinical significance was reported in RIPK4. Using research based exome analysis, RIPK4 had just a few months prior been identified as pathogenic for Bartsocas-Papas syndrome. While the clinical diagnostic report implied the KRT83 mutation as a more likely cause for the patient's phenotype, clinical correlation, literature review and use of computerized mutation analysis programs allowed us to identify the homozygous RIPK4 (c.488G>A; p.Gly163Asp) mutation as the underlying pathogenic change. Consequently, we expand the phenotype of Bartsocas-Papas syndrome to an attenuated presentation resembling Hay-Wells syndrome, lacking lethality and pterygia. In contrast to the autosomal dominant Hay-Wells syndrome, Bartsocas-Papas syndrome is autosomal recessive, implying a 25% recurrence risk.