Researchers investigating thyroid, pituitary and testicular function have made an unintentional discovery of an X chromosome-linked genetic disorder.

X-linked diseases are single-gene disorders that reflect the presence of defective genes on the X chromosome.

The mutations described in the report can cause an underactive thyroid gland with effects ranging from, in the case of severe defects, early developmental delay in young children to milder forms that, although asymptomatic, could increase the risk of cardiovascular disease.

In both cases, researchers say long-term thyroid replacement therapy is effective.