[Familial deficiency of thyroxine-binding globulin]

Area of Science:

• Genetics
• Endocrinology
• Human Physiology

Context:

• Congenital athyropexinemia is a rare genetic disorder affecting thyroid hormone transport.
• Understanding its inheritance patterns is crucial for genetic counseling and diagnosis.

Purpose:

• To report a family with congenital athyropexinemia.
• To elucidate the mode of inheritance and clinical presentation of the disorder.

Summary:

• A seven-generation family tree revealed X-chromosome-linked inheritance of congenital athyropexinemia.
• All 14 affected descendants (6 heterozygous females, 8 hemizygous males) were euthyroid.
• Notably, hemizygous patients exhibited absent or trace levels of thyroxine-binding globulin.

Impact:

• This study clarifies the X-linked inheritance of congenital athyropexinemia.
• It highlights the potential for euthyroid status despite the genetic anomaly.
• The findings underscore the complex relationship between thyroxine-binding globulin levels and thyroid function.