Glaucoma and Elliptocytosis.

ONLY a few instances of genetic linkage in man have so far been established. One of them is the linkage between hereditary elliptocytosis and the Rh antigens, the genes for which, in some families at least, are both carried on the same chromosome pair (Goodall, Hendry, Lawler, and Stephen, 1953; Marshall, Bird, Bailey, and Beckner, 1954; Morton, 1956; Clark, Donohoe, Finn, McConnell, Sheppard, and Nicoll, 1960; Bannerman and Renwick, 1962). One way of finding further linkages is to study those families, admittedly rare, in which two abnormal genes are transmitted from generation to generation. A well-known example is the family mentioned by Roberts (1945), in which elliptocytosis and hereditary telangiectasia were both present. Although the family was quite small, it provided good evidence that the two genes were not closely linked. The present study was occasioned by the discovery of hereditary elliptocytosis in a family in which mother and son both suffered from glaucoma. Although it first appeared that the occurrence of glaucoma in two generations might be fortuitous, examination of the family revealed ophthalmological anomalies in several other members and the existence of a hereditary element seems probable. Hereditary elliptocytosis is transmitted as a simple autosomal dominant, usually with complete penetrance (Wyandt, Bancroft, and Winship, 1941). The inheritance of glaucoma is much less clear-cut, but some of the confusion surrounding it has been due to the lack, until recently, of any sound classification. Now that the condition has been split up into well-defined groups a more distinct pattern is emerging. Most authorities agree, for instance, that the entity known variously as congenital glaucoma, hydrophthalmia, or buphthalmos is indisputably hereditary, inheritance being recessive and sex-controlled, with variable penetrance. It is becoming increasingly clear that the disease complex referred to as "primary glaucoma" is also hereditary. For more than a century reports have been published of primary glaucoma occurring in many members of a family. (For bibliography see Frangois, 1961.) Valuable though such work has been, it is only recently, with the advent of gonioscopy and the concept of openand closed-angle glaucoma, that a rational interpretation can be put upon the findings. It is quite likely, for instance, that some cases formerly described as "chronic simple glaucoma" were in fact examples of chronic congestive closed-angle glaucoma. It is now accepted that the two conditions of open-angle glaucoma and closed-angle glaucoma are entirely