Heredity of port-wine stains: investigation of families without a RASA1 mutation

The prevalence of capillary malformations, also known as port-wine stains (PWS), is 0.3%. Familial segregation can occur. The capillary malformation-arteriovenous malformation (CM-AVM) phenotype is caused by mutations in the RASA1 gene. In PWS familial cases, the inheritance is considered to be autosomal dominant with variable penetrance.

Investigation of the heredity of PWS among patients who attended the vascular anomaly section at the Department of Dermatology in Malmoe, Southern Sweden, between 1993 and 2004 and to study the involvement of the RASA1 gene in patients with a positive family history of PWS.

A total of 254 patients were examined and given a questionnaire regarding family history of PWS. The first group of 175 patients (109 females and 66 males) reported a negative family history. The other group of 65 patients (46 females and 19 males) reported a positive family history (50% parents or brothers and sisters).

The heredity of PWS was 27% (65/240). Twenty-one patients with a positive family history and relatives had no CM-AVM phenotype for mutations in the RASA1 gene.

PWS may have a stronger heredity component than it was reported earlier and inheritance should be considered when counseling a patient. RASA1 mutations do not explain the PWS in our patients.