A completely unexpected X chromosome-linked disorder has been identified in a big international study published this week in Nature Genetics.
Entitled "Loss-of-function mutations in IGSF1 cause an X-linked syndrome of central hypothyroidism and testicular enlargement", the study is co-authored by The University of Western Australia's Winthrop Professor Timothy Davis.
Professor Davis, from the School of Medicine and Pharmacology, said the role of his unit was to provide detailed clinical and laboratory data on thyroid, pituitary and testicular function in a patient with a confirmed mutation on the IGSF1 (immunoglobin superfamily) gene.
They also helped in the overall interpretation and reporting of the information to all the families recruited to the study.
Professor Davis said the mutations described in the report can cause an underactive thyroid gland with effects ranging from early developmental delay in young children if the defect is severe to milder forms that, although asymptomatic, could increase the risk of cardiovascular disease.
"In both situations, long-term thyroid replacement therapy is effective," he said.
The multi-national study involved several generations of 11 unrelated families around the world, including seven in Holland.
X-linked diseases are single-gene disorders that reflect the presence of defective genes on the X chromosome. This chromosome is present as two copies in females but only as one copy in males.