* Department of Human Genetics, Medical School, University of Cape Town, South Africa.
** Department of Orthopaedic Surgery, Medical School, University of the Witwatersrand, Johannesburg, South Africa.
Address for correspondence: Professor P. Beighton, Dept. of Human Genetics, Medical School, Observatory 7925, South Africa.
Supported by grants from the Jewish Board of Deputies, Cape Town, the South African Medical Research Council and the University of Cape Town's staff research fund.
Received: May 19, 1978.