Screening for carriers of genetic diseases by biochemical means.

For some genetic diseases the underlying biochemical anomaly is known. Through the gene dosage phenomenon it may therefore be possible to detect the more numerous clinically normal heterozygotes and so initiate a control programme. Such programmes need to be carefully and individually planned according to certain general principles derived in part from experience with prototype programmes. Laboratory data may be interpreted in relation to the prior probability of an individual being heterozygous or normal which may be known from the status of parents or other close relatives. Instigation of a control programme based on heterozygote testing is best achieved by working through a breed society (or its equivalent) which can control pedigree breeding through the control of registrations.