Inheritance of Pseudohypoparathyroidism

Sir .—The report of Tsang and associates 1 was of great interest; however, its value was somewhat marred by the lack of an adequate family history. McKusick 2 has summarized some of the questions that remain about the inheritance of pseudohypoparathyroidism, ie, dominant, sex-linked, and recessive forms may exist. Despite clinical similarity, however, genetic heterogeneity suggests the possibility of different pathways. For this reason it is important to document the pattern of inheritance; otherwise, lessons from one form might inappropriately be applied to another. While we are informed in the report of an affected sister, information is entirely lacking on the parents. Are they normal, or is one or the other affected? If one is affected, to what degree? Certainly the heterogeneity of expression of a single gene within a family is also important to our understanding. In this respect some mention of the presence or absence of other frequent