ATP7A Genetic Analysis Of Menkes Disease

Menkes disease (MD) is an X-linked recessive disorder of copper metabolism. It is caused by mutations in the ATP7A gene encoding a copper-translocating P-type ATPase. The incidence of this disorder is estimated to be 1 in 50,000 to 1 in 250,000 newborns. Menkes Disease is characterized by progressive neurodegeneration and connective tissue abnormalities. ATP7A gene (GenBank NM₀00052) maps to X-chromosome band Xq13.3, covering 141.24 kb of genomic DNA, and includes twenty-three exons. It encodes a 1500 amino acids ATP7A protein. To date, about 155 Menkes disease relevant mutations of ATP7A gene have been identified in patients from various ethnic backgrounds (Human Gene Mutation Database), but only one paper about two Menkes disease patients was reported from Taiwan and no findings have been reported previously in mainland of China.Objective:In this study, ATP7A mutations in six Chinese patients with Menkes disease were analyzed.Method:Six patients clinically diagnosed Menkes disease were included. All 23 exons and exon-intron boundaries of ATP7A gene were PCR amplified, directly sequenced and multiple ligation-dependent probe amplification (MLPA) for genomic DNA extracted from the peripheral white blood cells of six patients. The mutations have been proved by the DNA restriction enzyme digestion of PCR-amplified fragments or 100 allelosomal controls.Results:1. There were three hemizygous mutations found in PCR c.2589delTGAAGGA + c.2598delTT+c.2601delT+c.2603delT +c.2605del GTAGATGA (p.E864fsX883) in patient 1, c.3045delT(p.T1016fsX1018)in patient 2,c.3028 A>C (p.T1010P) in patient 3. Their mothers of patient 1 and patient 2 carried those heterozygous mutations in the same site of ATP7A gene.2. One exon (exon 10) deletion was found in MLPA, that is ,c.2173₂406del (p.F725_K802del) in exon10 in patient 4.The mother of patient 4 carried the heterozygous mutations in the same site of ATP7A gene.Conclusion 1. The four mutations were not reported in the world.2. The two hemizygous frame shift mutations, one missense mutation and exon deletion had been proved disease-causing mutations for four Chinese patients with Menkes disease. The two hemizygous frame shift mutations and the exon 10 deletion were inherited from their mother, respectively.3. MLPA, which is a newly developed method and used for the first time in China , is a rapid and reliable technique to detect the gross deletion of ATP7A gene.