原発性遠位尿細管性アシドーシスに伴った難聴の兄妹症例

Sensorineural Deafness and Renal Tubular Acidosis in Siblings

I．はじめに

　腎尿細管性アシドーシス（renal tubular acidosis以下RTAと略す）とは，近位尿細管での重炭酸イオンの再吸収障害，または遠位尿細管での水素イオン（滴定酸やアンモニアイオン）の排泄障害のため高クロール性アシドーシスをきたし，それにより種々の症状を呈する疾患であり，1935年Lightwood^1）により初めて記載され，1946年Albright^2）がtubular insufficiency without glomerular insufficiencyと明確に定義した。本症に難聴を伴うことを報告したのはRoyer and Broyer^3）（1967年）が最初であり，以来20数例のRTAと難聴例が報告されているのみである。

　今回，われわれは常染色体劣性遺伝と考えられる原発性遠位尿細管性アシドーシスと難聴を呈した兄妹例を経験したので報告する。

　The rare cases of siblings with sensorineural deafness combined with renal tubular acidosis were reported. They presented severe vomiting, polyuria, polydipsia and growth failure soon after their birth. They were diagnosed as having distal renal tubular acidosis found by urine acidification test (NH₄Cl loading test). Because of their delayed speech development, audiological examinations were performed, and severe sensorineural deafness; total deafness in a girl and a mixed deafness of 60 dB with air bone gap of 20 dB in a boy were found.

　As their parents showed normal renal functions and normal hearing, it was considered that the syndrome of renal tubular acidosis with sensorineural deafness was inherited by autosomal recessive trait.