Objectives: To assess the degree of relationship among individuals with hemangiomas and to evaluate the relative risk (RR) for family members of individuals with hemangiomas.
Design: Retrospective case-control study.
Setting: Utah Population Database.
Participants: Data sets of individuals of different ages with International Classification of Diseases, Ninth Revision (ICD-9) codes for hemangiomas were created from sources having medical records linked to the Utah Population Database. Controls were selected who matched cases for sex, birth year, and birthplace inside vs outside of Utah. Ten controls were selected per case, and sampling was performed without replacement. Kinship analysis tools were used to identify pedigrees having excess individuals with hemangiomas.
Main outcome measure: Using conditional logistic regression analysis, RR for hemangiomas among several kinship classes was determined.
Results: Identified were 2514 distinct cases 12 years or younger with ICD-9 code 228.01, and the RR for sibs in this group was significantly increased (RR, 2.52; P < .001). Seventy-three founder families had 5 or more affected descendants with cluster P values ≤ .01; familial standardized incidence ratios ranged from 1.64 to 9.50. Family sizes ranged from 546 to 22 291 descendants.
Conclusions: Sibs have increased RR for infantile hemangiomas, suggesting a potential genetic contribution to this likely multifactorial disease. Identification of large families with distantly related individuals will be helpful for future shared segment identification analyses.