Popliteal pterygium syndrome
An inherited condition with a web behind the knee.
(A pterygium is a winglike triangular membrane).</P> The syndrome goes by a number of names including the popliteal web syndrome and, more inclusively, the facio-genito-popliteal syndrome: > >Facial findings -- cleft palate (with or without cleft lip), pits in the lower lip, and fibrous bands in the mouth.
>Genital findings -- hypoplasia (underdevelopment) of the labia majora, malformation of the scrotum, and cryptorchidism (failure of the testes to descend into the scrotum).
>Limb findings -- an extensive web running from behind the knee down to the heel, malformed toenails, and webbed toes.
</LI></UL> The disorder is inherited in an autosomal dominant manner and is due to mutation of the IRF6 gene (interferon regulatory factor 6), the same gene as is mutated in Van der Woude syndrome, the most common syndromic form of cleft lip or palate