A 57 year old woman living independently in the community presented with four years of progressive spastic paraparesis and dementia. An extensive evaluation for the usual causes of these difficulties was unrevealing, but her serum phenylalanine concentration was markedly elevated and genetic analysis demonstrated mutations in the phenylalanine hydroxylase gene consistent with classic phenylketo...

Phenylketonuria is a rare inborn error of metabolism, which is believed to be associated almost always with some degree of mental retardation. The great majority of those affected are idiots or imbeciles; any with an intelligence quotient over 65 are rare enough to merit reporting (e.g., Low, Armstrong and Carlisle, 1956). Gowers' peripheral muscular dystrophy is also a very unusual disease in ...

We describe a method for neonatal screening for biotinidase (EC 3.5.1.12) deficiency. Biotinidase activity is assessed colorimetrically from dried samples of whole blood spotted on the same filter papers as used in the neonatal screening for phenylketonuria. After the reaction, samples from normal infants are characteristically purple, whereas those from affected individuals are straw-colored. ...