Korean J Med.  2011 Jun;80(6):718-722.

A Case of Familial Hypocalciuric Hypercalcemia Coexisting with Hypothyroidism

• Kim EJ
• Park SY
• Kang JG
• Kim CS
• Ihm SH
• Yoo HJ
• Lee SJ

Abstract

Familial hypocalciuric hypercalcemia (FHH) is a genetic disorder characterized by mild asymptomatic hypercalcemia, hypocalciuria, a decreased urinary calcium-creatinine ratio, and normal or elevated parathyroid hormone levels. FHH is caused by an inactivating heterozygous mutation of the calcium-sensing receptor (CaSR) gene. A 62-year-old woman was referred to our center because of inadequate glucose control. Her son had hypercalcemia. Biochemical and endocrine studies showed hypercalcemia, hypocalciuria, a decreased urinary calcium-creatinine ratio, normal parathyroid hormone levels, normal PTH-related peptide levels, decreased free T4, increased TSH, and thyroid antibody positivity. Direct sequencing analyses revealed a heterozygous mutation of G21R at exon 2 and a single nucleotide polymorphism of R990G at exon 7 of the CaSR gene. Here, we report a case of FHH associated with a heterozygous mutation and a single nucleotide polymorphism of the CaSR gene, which coexisted with autoimmune thyroiditis and hypothyroidism. To our knowledge, this is the first such case reported.

Keyword

Hypercalcemia; Calcium-sensing receptor; Autoimmune thyroiditis; Hypothyroidism

MeSH Terms

Exons
Female
Glucose
Humans
Hypercalcemia
Hypothyroidism
Middle Aged
Parathyroid Hormone
Parathyroid Hormone-Related Protein
Polymorphism, Single Nucleotide
Receptors, Calcium-Sensing
Thyroid Gland
Thyroiditis, Autoimmune
Glucose
Hypercalcemia
Parathyroid Hormone
Parathyroid Hormone-Related Protein
Receptors, Calcium-Sensing