Non-phenylketonuria hyperphenylalaninaemia in Northern Ireland: frequent mutation allows screening and early diagnosis.
Up to 10% of newborn children with a positive Guthrie test have non-phenylketonuria hyperphenylalaninaemia, i.e., mild elevation of serum phenylalanine that does not require dietary treatment. Depending on the relative frequencies of different phenylalanine hydroxylase mutations in a particular population, non-PKU HPA is usually caused by the combined effect of a mild HPA mutation and a severe PKU mutation. Presented here is a comprehensive analysis of non-PKU HPA in Northern Ireland. Of particular interest is one prevalent HPA mutation (T380M), which is present in over 70% of non-PKU HPA patients in Northern Ireland. Screening for this mutation is easy and inexpensive and can help confirm the diagnosis of non-PKU hyperphenylalaninaemia in the majority of cases at a very early stage. This may be clinically useful and reassuring for the parents. Other mutations described are V245A, L194P, and E390G.
Zschocke
J
J
Department of Medical Genetics, Belfast City Hospital, Northern Ireland.
Graham
C A
CA
Stewart
F J
FJ
Carson
D J
DJ
Nevin
N C
NC
D000293:Adolescent; D000592:Amino Acid Metabolism, Inborn Errors / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics*; D001483:Base Sequence; D002648:Child; D002675:Child, Preschool; D006580:Genetic Carrier Screening; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007494:Ireland / Q000453:epidemiology; D008099:Liver / Q000201:enzymology; D008969:Molecular Sequence Data; D009154:Mutation; D010649:Phenylalanine / Q000097:blood*; D010651:Phenylalanine Hydroxylase / Q000172:deficiency / Q000235:genetics; D010661:Phenylketonurias / Q000235:genetics; D016133:Polymerase Chain Reaction
D010649:Phenylalanine; D010651:Phenylalanine Hydroxylase