Congenital disorder exists in a newborn child even before birth and is call as birth imperfection. Basic variations from the norm are the most widely recognized kind of inherent imperfections. Causes and indications are variable. The substance which causes an irregularity in newborn children is called as teratogen. A few issue can be identified through pre-birth screening. Hereditary disorders in infant's are analyzed after birth. The vast majority of the deformities are caused because of legacy and are for the most part uncommon. Guys more often than not have undescended gonads. Little hands and feet, and almond-molded eyes, are not helpful symptomatic highlights in infants. A particular territory on the long arm of chromosome 15 is associated with the etiology of Prader– Willi disorder. The danger of repeat for Prader– Willi disorder is generally low.