twin, adoption and family studies have shown that genetic factors can play a role in the pathogenesis of obesity
however, while obesity runs in families, a Mendelian inheritance pattern is rarely evident
exceptions include uncommon disorders such as:
Prader-Willi syndrome (autosomal dominant, 1 in 25,000)
Bardet-Biedl syndrome (autosomal recessive, 1 in 100,000) syndromes
note that there have also been described monogenic forms of obesity such as congenital leptin deficiency and melanocortin-3 receptor mutations - these monogenic forms account for only a small proportion of cases of morbid obesity
British Heart Foundation (November 2004). Factfile - The causes of obesity.