Antall József szerk.: Orvostörténeti közlemények 87-88. (Budapest, 1979)

TANULMÁNYOK - Czeizel, Endre: A heredodegeneraciós tan történeti értékelése (angol nyelven)

the basis of Fay's data (1898) with regard to the progeny of 4471 deaf-mutes married among themselves

—the heredity of deafness and deaf-mutism respecitvely seemed to be probable. Pedigree analyses referred to autosomal recessive inheritance, on this ground deaf-mutism was taken as a single genetic disease. It was at that time that Csörsz and Tokay (1934) published a pedigree which proved beyond doubt the recessive inheritance of deaf-mutism, with the addition that it is linked to two different loci. Consequently: (i) the first appearance of deaf-mutism generally occurs in children of healthy parents, considering a larger number of cases the expectable rate of healthy and diseased children is 1:3 (in the offspring of II/9—

10; 11/13—14; III/l—

2; HI/3—

5 the rate is 8:20 that essentially means, probands left out, 1:3), and consanguinity of the parents is more frequent (IV/

18 proband's and IV/23 son's parents are cousins); (ii) two deaf-mute homozygotes of identical locus can have but deaf-mute children X-hezkotôU ichthyosis örökládését bizonyító csotàdfo. (Csörsz Károly, 1928) Fig. 6. The pedigree to prove first the X-linked iheritance of ichthyosis [see the marriage of IV/

11 and IV/

18]; (iii) from the marriage of a healthy and a deaf-mute generally healthy children (heterozygotes) descend [see e.g those born from the marriage of III/

14 and III/

18 ; (iv) deaf-mute and healthy parents can produce deaf-mutes if the healthy parent is a heterozygote, too, i.e. a mutant gene carrier; it can be referred to by family occurrence of deaf-mutism [see the marriage of III/

8 and HI/6] ; (v) it may happen that deaf-mute parents have healthy children, but in that case deaf-mutism is due to genes of two different loci [see the marriage of IV/3 and IV/8; in this case children are heterozygotes]; and finally (vi) acquired deafness can never be inherited [see the offspring of IV/

6]. The pedigree that Károly Csörsz