Genetic study of Welsh gypsies.

A South Wales gypsy kindred of Romany origin had a high incidence of phenylketonuria along with other recessively inherited disorders. There was a high degree of consanguinity (F = 0-017) with an excess of non-specific mental subnormality among known consanguineous matings. Phenylketonuria and a number of other recessively inherited disorders have been recorded from other Romany gypsy populations, but it is uncertain whether this results from a generally high gene frequency for the disorders or from consanguinity and other more local factors.