Novel mutations in EVC cause aberrant splicing in Ellis-van Creveld syndrome

Ellis-van Creveld syndrome (EvC) is a rare autosomal recessive disorder characterized by disproportionate chondrodysplasia, postaxial polydactyly, nail dystrophy, dental abnormalities and in a proportion of patients, congenital cardiac malformations. Weyers acrofacial dysostosis (Weyers) is another dominantly inherited disorder allelic to EvC syndrome but with milder phenotypes. Both disorders can result from loss-of-function mutations in either EVC or EVC2 gene, and phenotypes associated with the two gene mutations are clinically indistinguishable. We present here a clinical and molecular analysis of a Chinese family manifested specific features of EvC syndrome. Sequencing of both EVC and EVC2 identified two novel heterozygous splice site mutations c.384+5G>C in intron 3 and c.1465-1G>A in intron 10 in EVC, which were inherited from mother and father, respectively. In vitro minigene expression assay, RT-PCR and sequencing analysis demonstrated that c.384+5G>C mutation abolished normal splice site and created a new cryptic acceptor site within exon 4, whereas c.1465-1G>A mutation affected consensus splice junction site and resulted in full exon 11 skipping. These two aberrant premRNA splicing processes both produced in-frame abnormal transcripts that possibly led to abolishment of important functional domains. To our knowledge, this is the first report of EVC mutations that cause EvC syndrome in Chinese population. Our data revealed that EVC splice site mutations altered splicing pattern and helped elucidate the pathogenesis of EvC syndrome.