Popliteal pterygium syndrome

The popliteal Pterygiumsyndrome (PPS ) is an inherited gene defect that affects the face, limbs and the genital area. The syndrome is also called popliteal pterygium syndrome, facial - genito - popliteal syndrome or Fèvre - Languepin syndrome. The term PPS was coined by Gorlin in 1968 on the basis of the extremely rare malformations, the popliteal pterygium ( an intergrowth of the knee ).

Clinical Features

The popliteal pterygium syndrome symptoms of vary widely, but include the following:

• Findings on the limbs: a connective tissue running from the knee down to the heel (90 %), syndactyly.
• Findings in the face: Cleft lip and cleft palate with or without cleft lip ( 75%), Unterlippenfistel (40 %) and adhesions in the throat area ( synechiae ) (25 %).
• Findings in the genital area (50 %): hypoplasia of the labia majora, malformation of the scrotum and malposition of the testis.

Epidemiology

The diagnosis of PPS was carried out in different ethnic groups, including Caucasian, Japanese, and sub-Saharan Africa. Men and women are equally affected by this syndrome. Since the malformation is very rare, the number of people affected is difficult to estimate. However, it is less than 1 part in 10,000.

Genetics

The gene locus for PPS was discovered on the first chromosome in 1999. The malformation is inherited as an autosomal dominant trait. It arises due to a mutation of the IRF6 gene.

Resemblance to the Van der Woude syndrome

Van der Woude syndrome ( VDWS) and the popliteal Pterygiumsyndrome (PPS) are allelic variants of the same change caused by different mutations of the same gene. PPS contains all the features of VDWS and additionally the popliteal pterygium, synechiae, pronounced toes / nails abnormalities, syndactyly, and genito - urinary malformations.