False regarding eating disorder is:

D i.e. Penetrance is 50%Ref: Biological Psychiatry (edited by Hugo A. H. D'haenen, Johan A. Den Boer, Paul Willner) and Yilmaz Z, Hardaway Ja, Bulik Cm. Genetics and of Eating Disorders.Advances in Genomics and Genetics page 131-150Explanation:Pathological problems associated with eating are many, like pica, overeating, under-eating.By and large, eating disorders denote: o Anorexia nervosa (AN).Bulimia nervosa (BN); andBinge eating disorder.Etiology-wise, they have more genetic contribution (than many psychiatric disorders).Studies (especially twin-studies) indicate upto 74% of phenotypic variation can be accounted by additive genetic factors .Penetrance is defined as the probability of expression of an allele. It can be complete/incomplete; highly penetrant/low penetrant. In eating disorders, studies show higher degree of penetrance (> 50%, some studies state upto 90%) (option (d))Like any other psychiatric disorder, eating disorders have neuro-humoral underpinnings. Brain regions and chemicals which are involved in appetite are implicated.Neurological substrates are mainly hypothalamus, anterior frontal regions.Till date, all monoamine neurotransmitter systems were implicated in AN and BN. Among the NTs, dysregulation of 5-HT system appears to have robust data (option (a))Starvation and other symptoms of eating disorders are mutually reinforcing each other, may be leading to a vicious cycle as in animal models (p. 1119, Biological Psychiatry).