No abstract

Ectrodactyly is a congenital limb malformation that involves a central reduction defect of the hands andlor feet which is frequently associated with other phenotypic abnormalities. The condition appears to be genetically heterogeneous and recently it has been demonstrated that mutations in the p63 gene, a homologue of the tumor suppressor gene 17.53, are the cause of at least four autosomal dominant genetic syndromes which feature ectrodactyly: ectrodactyly, ectodermal dysplasia, and facial clefting (EEC), split handlsplit foot malformation (SHFM), limb-mammary syndrome (LMS), and acro-dermato-ungual-lacrimal-tooth syndrome (ADULT). In this study, genetic analysis of the p63 gene in a group of 13 patients with ectrodactyly (syndromic and isolated) was performed. Four patients with syndromic ectrodactyly had p63 heterozygous point mutations that affect the DNA binding domain of the protein. One of these subjects exhibited the typical features of EEC syndrome as well as ankyloblepharon being, to our knowledge, the first case combining these traits. This finding supports the view of a clinical overlap in this group of autosonial dominant syndromes caused by p63 mutations and demonstrates that there are exceptions in the previously established p63 genotype-phenotype correlation.

The recognition of microspherophakia in two siblings carrying a novel WFS1 mutation expands the clinical and molecular spectrum of Wolfram syndrome.

Craniofrontonasal syndrome (CFNS) is an X-linked disorder caused by mutations in the EFNB1 gene and characterized by distinctive craniofacial and digital malformations. In contrast with most X-linked traits, female patients with CFNS display a more severe phenotype than males. In this report, the clinical, molecular and RNA expression analyses of a female subject with CFNS are described. A novel c.445_449delGAGGG deletion in exon 3 of EFNB1 was demonstrated in this patient. To assess the effect of this novel mutation at the transcript level, the expression of EFNB1 mRNA was studied by quantitative RT-PCR. To our knowledge, this is the first time that an EFNB1 transcript carrying a truncating mutation in exon 3 is demonstrated to undergo degradation by nonsense-mediated mRNA decay. Our results expand the mutational spectrum of CFNS and add to the functional consequences of truncating EFNB1 mutations.