Background: The syndrome of generalized resistance to thyroid hormones is more frequent than was thought.
Case reports: A 13-year old girl was examined for her short stature. Evaluation of her thyroid function showed increased levels of IT3 and IT4 and normal value of TSH; she also had mosaic Turner's syndrome. Her cousin was rapidly diagnosed as suffering from the same syndrome because of moderately high thyrotropic levels found during neonatal screening; this syndrome was confirmed by molecular biology tests. Five generations of this family were identified as being affected with a pattern indicating autosomal dominant inheritance.
Conclusion: The clinical manifestations of familial generalized resistance to thyroid hormones vary but this syndrome is easy to biologically confirm. The importance of diagnosing affected children as early as possible should be emphasized, as in such cases their development must be closely monitored particularly where their growth and neurodevelopment are concerned.