Popliteal pterygium syndrome (PPS) is an inherited condition affecting the face, limbs, and genitalia. The syndrome goes by a number of names including the popliteal web syndrome and, more inclusively, the facio-genito-popliteal syndrome. The term PPS was coined by Gorlin et al. in 1968 on the basis of the most unusual anomaly, the popliteal pterygium (a web behind the knee). Symptoms and signs
Clinical expressions of PPS are highly variable, but include the following:
Limb findings: an extensive web running from behind the knee down to the heel (90%), malformed toenails, and webbed toes. Facial findings: cleft palate with or without cleft lip (75%), pits in the lower lip (40%), fibrous bands in the mouth known as syngnathia (25%), and tissue connecting the upper and lower eyelids
Genital findings (50%): hypoplasia of the labia majora, malformation of the scrotum, and cryptorchidism. Genetics
The genetic locus for PPS was localized to chromosome 1 in 1999. The disorder is inherited in an autosomal dominant manner and is due to mutation of the IRF6 gene. Most reported cases are sporadic; advanced parental age is found in a number of these cases, suggesting new mutations.The term PPS has also been used for two rare autosomal recessively inherited conditions: Lethal PPS and PPS with Ectodermal Dysplasia. Although both conditions feature a cleft lip/palate, syngnathia, and popliteal pterygium, they are clinically distinguishable from the autosomal dominant case.
While infectious agents are the most common cause, a genital ulcer may also be the result of non-infectious causes such as Behcets syndrome, lupus, or psoriasis.Since it is difficult to determine a cause of a genital ulcer from history, examination, and population characteristics alone, further testing is often needed. The most common diagnostic tools used are targeted towards the most common etiologies of genital ulcers: syphilis (syphilis serology, PCR testing, or dark-field examination), herpes simplex virus (PCR, culture, or type specific HSV antibodies), and haemophilus ducreyi (culture on special media currently not widely available in most hospital systems) if the individual is in a known endemic region. Further diagnostic tools such as a biopsy or culture are often utilized if ulcers appear unusual or do not respond as expected to therapy.Since genital ulcers are often infectious in origin, there is an increased risk of acquiring HIV in a HIV negative patient through viral introduction through the open sore Conversely, there is an increased risk of HIV transmission through increased shedding of viral HIV in the presence of a genital ulcer in a patient with a history of HIV. The CDC recommends testing for HIV in any individual presenting for a genital ulcer who does not already have a history of HIV.