Question

As a child’s IQ gradually decreases and they exhibit deep intellectual weakness again, along with a recurrence of rebellious and abusive psychology, their entire body hair and skin are gradually turning white; their muscles may continuously twitch, and they seem a bit foolish. Is it ketosis or phenylketonuria?

Answer

An enzyme defect in the metabolism pathway of phenylalanine prevents it from being converted into tyrosine, leading to the accumulation of phenylalanine and its ketoacids, which are then excreted in large quantities in the urine. Ketosis refers to the presence of large amounts of ketone bodies in the urine, which are mainly produced by fat metabolism. The differences have been explained; one is a metabolic blockage in the breakdown of phenylalanine, and the other is due to the extensive breakdown of fat. The former is often a congenital genetic disease, while the latter is commonly seen in diabetes.