paternal uniparental disomy of chromosome 20
Paternal uniparental disomy of chromosome 20 is a very rare chromosomal anomaly in which both copies of chromosome 20 are inherited from the father. The main features described are high birth weight and/or early-onset obesity, relative macrocephaly, and tall stature. Most patients were ascertained during sporadic pseudohypoparathyroidism type 1b testing and have UPD involving variable segments of the long arm of chromosome 20.