Evidence for genetic heterogeneity in Carvajal syndrome

Carvajal syndrome is a rare syndrome with woolly hair, palmoplantar keratosis and dilated cardiomyopathy. The inheritance of the mutation is autosomal recessive. As a causal gene, the desmoplakin gene (DSP) has so far been identified; it encodes an essential component of desmosomes, a cell-cell structure aimed at keeping cells attached to each other in tissues in which cells are often exposed to strong shear forces. Recently, familial cases of an autosomal dominant Carvajal syndrome were documented with a new feature: hypo/oligodontia. A mutation in the DSP gene was also evidenced in these latter cases. A patient was seen for cardiogenetic consultation at the University Hospital of Lyon with cardiac failure involving first degree atrioventricular block, complete left bundle branch block, non-compaction of the apex of the left ventricle and a dilated cardiomyopathy. A coronarography disclosed a complete thrombosis of the right coronary artery. At examination, he had also woolly hair, mild palmoplantar keratosis and missing teeth (essentially molars and premolars). His family history was uninformative. His DNA was screened for mutations in the DSP and plakoglobin genes but no mutation could be found. This case suggests that Carvajal syndrome with hypo/oligodontia is a heterogeneous condition in which genes other than DSP might be involved, although we cannot rule out a mutation in this gene consisting in a deletion of a single exon or a gene rearrangement.