[DNA diagnosis in endocrinological disease--pituitary disease]

Endocrine disorders have long been diagnosed by symptoms, before hormones were able to be measured by immunoassays. Recently, as molecular biological methods developed, DNA diagnosis has become available in many diseases including endocrine disorders. We present here DNA diagnosis in connection with anterior pituitary hormones. Our studies on thyrotropin (TSH) producing pituitary adenomas showed that TSH beta-subunit mRNAs of the adenomas were the same as those from normal pituitary tissues. Congenital isolated TSH deficiency is rare disease causing hypothyroidism including cretinism, severe mental and growth retardation. We have studied 3 families with consanguineous marriage and 2 families which were descendants of closed colonies. The molecular pathogenesis were elucidated in the cases of 3 Japanese families with consanguineous marriage. They had a same missense mutation in the 2nd exon of the TSH beta-subunit gene which made a restriction enzyme site, and could be analyzed either by genomic Southern blot analyses or by restriction enzyme digestion after amplification of genomic DNA by PCR. Congenital deficiency of growth hormone, prolactin, and TSH was first described in Snell dwarf mice. The gene encoding the nuclear factor Pit-1/GHF-1, which transactivates promoters of both growth hormone gene and prolactin gene, was shown to be the cause of Snell dwarf mice. A similar human case arose from a family with consanguineous marriage, and the relation with the pit-1/GHF-1 gene is now under study.