Fabry disease superimposed on overt autoimmune hypothyroidism

Fabry disease (FD) is an X-linked recessive disorder caused by lysosomal α-galactosidase A deficiency. FD is characterized by the systemic accumulation of globotriaosylceramide with involvement of the heart, kidney, brain and gastrointestinal system. Recently, nonautoimmune thyroid dysfunction was recognized as an additional clinical feature of FD. In the present study, we describe a patient suffering from FD superimposed on overt autoimmune hypothyroidism. The patient was an 11-yr-old boy who presented with goiter and stunted growth, and was diagnosed with primary hypothyroidism due to autoimmune thyroiditis. During levothyroxine replacement therapy, the patient complained of burning pain in his feet and was diagnosed as suffering from FD based on low blood α-galactosidase A activity. In conclusion, we have described the first FD patient preceded by overt autoimmune hypothyroidism.