An update on the molecular analysis of classical galactosaemia patients diagnosed in Spain and Portugal: 7 new mutations in 17 new families

BACKGROUND AND OBJECTIVES:Classical galactosaemia is an inherited metabolic disorder due to mutations in the galactose-1-phosphate uridyltransferase gene (GALT). We previously reported molecular analysis of 83 Spanish and Portuguese unrelated galactosaemic patients. Here we present the results of another seventeen unreported affected individuals. MATERIAL AND METHODS:DNA from patients was PCR-amplified and sequenced following standard protocols. RESULTS:Twelve patients diagnosed in Spain were studied. We detected five alleles carrying p.Q188R, accounting for 21%. Other six alleles (25%) were identified with the mutation p.K285N. We also identified six novel mutations: p.Q9X, c.328+2T>C, p.I170N, p.C180F, p.V233L and p.P257L. Taking into account all the Spanish galactosaemic diagnosed patients, mutation p.Q188R is still the most frequent mutation identified (44.4%). In five new Portuguese patients, five alleles p.Q188R were detected, representing 50%. One novel mutation (p.F171C) was identified. CONCLUSIONS:Our results confirm our previous observations that p.Q188R is the most frequent mutation in Iberian Peninsula galactosaemic patients (49%), and that Portuguese and Spanish genotypes differ.