Symptoms and Signs - Limb findings: extensive web from behind the knee to the heel, malformed toenails, webbed toes - Facial findings: cleft palate with or without cleft lip, pits in the lower lip, fibrous bands in the mouth (syngnathia), tissue connecting upper and lower eyelids - Genital findings: hypoplasia of the labia majora, malformation of the scrotum, cryptorchidism - Other findings: popliteal pterygium, distinct toe/nail abnormality, syndactyly

Genetics - Autosomal dominant inheritance - Mutation of the IRF6 gene - Most cases are sporadic, suggesting new mutations - Lethal PPS and PPS with Ectodermal Dysplasia are rare autosomal recessively inherited conditions - Lethal PPS is differentiated by microcephaly, corneal aplasia, ectropion, bony fusions, hypoplastic nose, and absent thumbs

Relationship to Van der Woude syndrome - Van der Woude syndrome and PPS are allelic variants of the same condition - PPS includes all the features of VDWS, plus additional abnormalities - Additional abnormalities in PPS include popliteal pterygium, syngnathia, distinct toe/nail abnormality, syndactyly, and genito-urinary malformations

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Epidemiology - PPS has been diagnosed in several ethnic groups, including Caucasian, Japanese, and sub-Saharan African - Males and females are equally likely to have the syndrome - Incidence rate is difficult to estimate but is less than 1 in 300,000