Carbonic anhydrase II deficiency syndrome--clinico-pathological, biochemical and molecular studies.

We reported on three unrelated Japanese families with carbonic anhydrase II (CA II) deficiency syndrome. In the present study, the CA II gene was sequenced in the family of a patient with hybrid type renal tubular acidosis whose parents were nonconsanguineous, and a T to G transition at exon 2 was identified. The change results in the substitution of the stop codon (TAG) at position 40 for Tyr (TAT). The maternal and paternal mutations were the same suggesting that they were obligate heterozygotes. This is a novel mutation in the CA II deficiency syndrome, which has not been described before.