This gene encodes a transmembrane protein containing six epidermal growth factor repeats. The protein is involved in the differentiation of several cell types, including adipocytes; it is also thought to be a tumor suppressor. It is one of several imprinted genes located in a region of on chr 14q32. Certain mutations in this imprinted region can cause phenotypes similar to maternal and paternal uniparental disomy of chromosome 14 (UPD14). This gene is expressed from the paternal allele. A polymorphism within this gene has been associated with child and adolescent obesity. The mode of inheritance for this polymorphism is polar overdominance; this non-Mendelian inheritance pattern was first described in sheep with the callipyge phenotype, which is characterized by muscle hypertrophy and decreased fat mass.