DIVERSE MUTATIONS IN PATIENTS WITH MENKES DISEASE OFTEN LEAD TO EXON SKIPPING

Fibroblast cultures from 12 unrelated patients with classical Menkes d isease were analyzed for mutations in the MNK gene, by reverse transcr iption-PCR (RT-PCR) and chemical cleavage mismatch detection. Mutation s were observed in 10 patients, and in each case a different mutation was present. All of the mutations would be predicted to have adverse e ffects on protein expression. Mutations that resulted in splicing abno rmalities, detected by RT-PCR alone, were observed in six patients and included two splice-site changes, a nonsense mutation, a missense mut ation, a small duplication, and a small deletion, Chemical cleavage an alysis of the remaining six patients revealed the presence of one nons ense mutation, two adjacent 5-bp deletions, and one missense mutation. A valine/leucine polymorphism was also observed. These findings, comb ined with the prior observation of deletions in 15%-20% of Menkes pati ents, suggest that Southern blot hybridization and RT-PCR will identif y mutations in the majority