( 1 ) hereditary lesions fall into three groups : - ( a ) malformations : present at birth . ( b ) abiotrophies : at birth the tissue is fully differentiated but it undergoes degenerative changes at some period in post-natal life . ( c ) phakomatoses : a group possessing features of the two previous groups and some features of neoplasms . ( 2 ) the conception of abiotrophy draws attention to a large group of affections which have a hereditary character and develop in apparently normal tissues , making their appearance in different families at different periods of life .
C1708351
hereditary lesions
C0265316
phakomatoses