[A genealogical study of Steinert's disease (author's transl)].

As a result of retrospective genealogical studies on 41 cases of myotonic dystrophy, the authors have found: 1) sound arguments to support the hypothesis of anticipation often discussed in association with this disease; 2) a high rate of mortinatality in the progeny of affected females; this aspect merits being taken into consideration in genetic counselling and should be reported to obstetricians. Its pathogenetic determination still remains obscure; 3) a relative frequency of illegitimacy in familes with affected fathers. On the basis of the low fertility associated with the disease, the authors postulate that new mutations may not be rare. Finally, they emphasize two little known symptomatic features, the first being the frequency of lithiasis, the second the frequency of neoplasms. This latter observation, however, still requires confirmation.