構成員の約半数に発病をみた先天性筋強直症（MYOTONIA CONGENITA）の一家系例

A PEDIGREE OF DOMINANTLY INHERITED MYOTONIA CONGENITA

I．緒言

　Thomsen （1876）は自己自身ならびに自己の家系に遺伝性に発現した，随意運動開始初期の筋強直性運動障害を始めて報告した。Strümpell （18　81）はこれを一個の疾患単位としてMyotonia　congenitaと命名し，さらにWestphal （1883）はこれをThomsensche Krankheitと名づけた。以来多数の著者によつて本疾患の症例報告が加えられているが，現在においても本疾患の病因，および他の類似疾患との遺伝因子的な異同については，なお多くの不明な点を残しており，今後の研究に期待される所が少くない。

　われわれは最近外来で定型的なMyotonia con-genitaの1例を発見し，さらに進んで，その家系について調査した結果，家系構成員の多数に同一疾患の発現を確認したので，その結果を報告し，本疾患の解明に寄与したいと思う。

Four generations of one family which show-ed successively typical pictures of myoto-nia congenita (Thomsen's disease) were ob-served, and following results wern obtained.

1) Among its twenty-six totale members, who were above the age of 5 years, we con-firmed a typical picture of myotonia congeni-ta in nine cases and incomplete formes in two cases.

2) The age of the onset was between from 4 to 8 years after birth. Regarding to the manifestation rate of the disease, there was no significant difference in both sexes. The developement of myotonic disorders began in legs or arms, thereafter masticating muscles and orbital muscles were affected. Myotonic disorders lasted ever constantly, although they were increased. temporally by exhaus-tion, exposure in cold and in tense situation and in female by pregnancy.

3) In a female case, who had no complaint of myotonic disorders or any other and seem-ed to be quite free from the attack of the disease, some disputable findings were re-vealed by electromyographic examination.

4) Biochemical examinations of serum de-monstrated the slight decrease of potassium in density.