One too many: intellectual disability secondary to undiagnosed phenylketonuria

• Published in: Hong Kong medical journal = Xianggang yi xue za zhi Vol. 22; no. 5; pp. 506 - 508
• Main Authors: Hui, J, Chong, S C, Law, L K, Lee, L K, Chang, S, Yau, P, Yuen, Y P
• Format: Journal Article
• Language: English
• Published: China Hong Kong Academy of Medicine 01.10.2016
• Subjects: Amino acids; Child, Preschool; Children & youth; Creatinine; Diet; Families & family life; Humans; Intellectual disabilities; Intellectual Disability - etiology; Male; Medical diagnosis; Medical screening; Metabolism; Metabolites; Mutation; Patients; Pediatrics; Phenylalanine - blood; Phenylketonuria; Phenylketonurias - complications; Phenylketonurias - diagnosis; Urine; Hong Kong China; China; Intellectual disability; Phenylketonurias/diagnosis
• ISSN: 1024-2708; 2226-8707
• DOI: 10.12809/hkmj144500

BH4 is an essential cofactor for PAH, TH, and TPH We describe a 2-year-old boy who was referred by the Maternity Child Health Clinic to the Department of Paediatrics in June 2014 for assessment of developmental delay. Another mutation affecting the same amino acid p.Leu287Gly has been reported previously in patients with phenylketonuria (PKU).2 In-silico analyses by four prediction software (PolyPhen-2, SIFT, Mutation Taster, PON-P2) also consistently predicted that the mutation is pathogenic. [...]PAH c.860T[greater than]C (p.Leu287Pro) is highly likely to be a pathogenic mutation. PAH gene dosage analysis by multiplex ligation probe amplification (SALSA MLPA probemix P055-C1 PAH) did not detect any PAHgross deletion or duplication. [...]the secondPAH mutation of this patient remained unidentified. Hong Kong cannot afford to have more intellectual disability as a result of the unavailability of PKU screening. [...]this programme becomes universally available, we advocate plasma amino acid and urine organic acid analysis to be incorporated into the diagnostic workup for all children with unexplained developmental delay, intellectual disability, behavioural problems, and autistic spectrum disorders. 1.