<prompt> Paternal disomy is found in?Prader-Willi syndromeAngelman syndromeFragile X syndromeHydatiform mole  <response>: Ans. B. Angelman syndromea. Paternal uniparental disomy upd15pat results from the fertilization of an oocyte that is nullisomic for chromosome 15 and the postzygotic duplication of the paternal chromosome. Upd15pat is associated with the loss of function of the maternally expressed UBE3A gene, which leads to Angelman syndrome AS.b. Angelman syndrome AS is a neurological disorder first described in 1965 by an English physician named Dr. Harry Angelman.Symptoms are usually evident after the age of three, and are characterized by severe congenital mental retardation, unusual facial appearance, and muscular abnormalities.c. Maternal uniparental disomy for chromosome 15 upd15mat is the second most common finding in patients with Prader-Willi syndrome PWS.d. PWS is characterized by neonatal hypotonia, hypogonadism, hyperphagia leading to obesity, short stature, small hands and feet, behavioral problems and mental retardation. 