title: Exon deletions of the phenylalanine hydroxylase gene in Italian hyperphenylalaninemics.
abstract: A consistent finding of many studies describing the spectrum of mutant phenylalanine hydroxylase (PAH) alleles underlying hyperphenylalaninemia is the impossibility of achieving a 100% mutation ascertainment rate using conventional gene-scanning methods. These methods include denaturing gradient gel electrophoresis (DGGE), denaturing high performance liquid chromatography (DHPLC), and direct sequencing. In recent years, it has been shown that a significant proportion of undetermined alleles consist of large deletions overlapping one or more exons. These deletions have been difficult to detect in compound heterozygotes using gene-scanning methods due to a masking effect of the non-deleted allele. To date, no systematic search has been carried out for such exon deletions in Italian patients with phenylketonuria or mild hyperphenylalaninemia. We used multiplex ligation-dependent probe amplification (MLPA), comparative multiplex dosage analysis (CMDA), and real-time PCR to search for both large deletions and duplications of the phenylalanine hydroxylase gene in Italian hyperphenylalaninemia patients. Four deletions removing different phenylalanine hydroxylase (PAH) gene exons were identified in 12 patients. Two of these deletions involving exons 4-5-6-7-8 (systematic name c.353-?_912+?del) and exon 6 (systematic name c.510-?_706+?del) have not been reported previously. In this study, we show that exon deletion of the PAH gene accounts for 1.7% of all mutant PAH alleles in Italian hyperphenylalaninemics.
authors: Laboratorio di Genetica Molecolare, Associazione Oasi Maria SS. (I.R.C.C.S.), Troina (EN), Italy.
authors: Francesco
authors: F
authors: Cali
authors: Giuseppa
authors: G
authors: Ruggeri
authors: Mirella
authors: M
authors: Vinci
authors: Concetta
authors: C
authors: Meli
authors: Carla
authors: C
authors: Carducci
authors: Vincenzo
authors: V
authors: Leuzzi
authors: Simone
authors: S
authors: Pozzessere
authors: Pietro
authors: P
authors: Schinocca
authors: Alda
authors: A
authors: Ragalmuto
authors: Valeria
authors: V
authors: Chiavetta
authors: Salvatore
authors: S
authors: Micciche
authors: Valentinox
authors: V
authors: Romano
mesh_terms: D004252:DNA Mutational Analysis / Q000379:methods*; D018450:Disease Progression; D005091:Exons / Q000235:genetics; D005787:Gene Frequency; D006801:Humans; D007558:Italy; D010651:Phenylalanine Hydroxylase / Q000235:genetics* / Q000378:metabolism; D010661:Phenylketonurias / Q000453:epidemiology / Q000235:genetics* / Q000503:physiopathology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017384:Sequence Deletion / Q000235:genetics
chemical_list: D010651:Phenylalanine Hydroxylase