Is familial pityriasis rubra pilaris inherited ?
Familial pityriasis rubra pilaris usually has an autosomal dominant inheritance pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. Affected individuals usually inherit the condition from one affected parent. However, the condition is said to have incomplete penetrance because not everyone who inherits the altered gene from a parent develops the condition's characteristic skin abnormalities.  The other types of pityriasis rubra pilaris are sporadic, which means they occur in people with no history of the disorder in their family.