Phenylketonuria

Phenylketonuria (PKU) is a common amino acid metabolic disorder caused by an enzyme deficiency in the phenylalanine metabolic pathway. This deficiency prevents phenylalanine from being converted into tyrosine, leading to the accumulation of phenylalanine and its keto acids, which are then excreted in large quantities in the urine. PKU is an autosomal recessive genetic disorder, characterized by both parents being carriers of the pathogenic gene variant, usually without developing the disease themselves. Their children, however, have a 25% chance of inheriting pathogenic variants from both parents, leading to the onset of the disease. Common symptoms of PKU include intellectual disability, developmental delay, neuropsychiatric abnormalities, skin rashes, and a distinctive musty odor in sweat and urine.