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

Background: 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. Objective: Investigation of the heredity of PWS among patients who attended the vascular anomaly section at the department of dermatology in Malmoe, Southern Sweden, between 1993-2004 and to study the involvement of the RASA1 gene in patients with a positive family history of PWS. Subjects and methods: 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). Results: 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. Conclusion: PWS may have a stronger heredity component than earlier reported and inheritance should be considered when counselling a patient. RASA1 mutations do not explain the PWS in our patients.