Lymphoedema-distichiasis and FOXC2: unreported mutations, de novo mutation estimate, families without coding mutations.

Lymphoedema-distichiasis (LD) is a syndromic form of primary lymphoedema, where mutations in the gene for the developmental transcription factor FOXC2 have been shown to be causative. The disorder has been considered very rare, but our group has now ascertained 34 families and 11 sporadic cases in the UK. Two families with LD have no mutation in the coding region of FOXC2, although both are consistent with linkage to the FOXC2 locus. A deletion has been ruled out as a possible cause of LD in these families, leaving promoter mutations as the most likely cause. Sixteen previously unpublished mutations are reported, plus an estimate of the frequency of new mutations in this disorder.