A new case of α‐N‐acetylgalactosaminidase deficiency with angiokeratoma corporis diffusum, with Ménière's syndrome and without mental retardation

α‐N‐acetylgalactosaminidase (α‐NAGA) deficiency is a rare hereditary lysosomal storage disease, and only three α‐NAGA‐deficient patients with angiokeratoma corporis diffusum (Kanzaki) have been described. We report a further case in a 47‐year‐old Japanese woman, the product of a consanguineous marriage. The remarkable findings in this patient were her normal intelligence, Ménière's syndrome, disturbance of peripheral sensory nerves, hearing loss and cardiac hypertrophy. α‐NAGA enzyme activity in her plasma was 0·77% of the normal value. Other enzyme activities, such as α‐galactosidase, β‐galactosidase, α‐l‐fucosidase, β‐mannosidase and aspartylglucosaminidase, were within normal limits. A large quantity of amino acid O‐glycans was detected in her urine. Gene analysis revealed a novel point mutation (G→A transition) at nucleotide 11018 (986 in the cDNA) resulting in an Arg‐329‐Gln substitution. Kanzaki disease has the same enzyme defect as Schindler disease, but the manifestations are quite different.