Vitamin D deficiency in two young adults with biochemical findings resembling pseudohypoparathyroidism type I and type II

Toshiro Seki; Michiko Yamamoto; Hironari Kimura; Mika Tsuiki; Masami Ono; Nobuhiro Miki; Kazue Takano; Kanji Sato

doi:10.1507/endocrj.K10E-097

Toshiro Seki, Michiko Yamamoto, Hironari Kimura, Mika Tsuiki, Masami Ono, Nobuhiro Miki, Kazue Takano, Kanji Sato

Author information

Toshiro Seki
Department of Medicine, Institute of Clinical Endocrinology, Tokyo Women’s Medical University, Tokyo, Japan
Michiko Yamamoto
Faculty of Human Care, Teikyo Heisei University, Tokyo, Japan
Hironari Kimura
Department of Medicine, Institute of Clinical Endocrinology, Tokyo Women’s Medical University, Tokyo, Japan
Field of Pathophysiology, Treatment of Thyroid and Parathyroid Disease, Graduate School of Medicine, Tokyo Women’s Medical University, Tokyo, Japan
Mika Tsuiki
Department of Medicine, Institute of Clinical Endocrinology, Tokyo Women’s Medical University, Tokyo, Japan
Masami Ono
Department of Medicine, Institute of Clinical Endocrinology, Tokyo Women’s Medical University, Tokyo, Japan
Nobuhiro Miki
Department of Medicine, Institute of Clinical Endocrinology, Tokyo Women’s Medical University, Tokyo, Japan
Kazue Takano
Department of Medicine, Institute of Clinical Endocrinology, Tokyo Women’s Medical University, Tokyo, Japan
Kanji Sato
Department of Medicine, Institute of Clinical Endocrinology, Tokyo Women’s Medical University, Tokyo, Japan
Field of Pathophysiology, Treatment of Thyroid and Parathyroid Disease, Graduate School of Medicine, Tokyo Women’s Medical University, Tokyo, Japan

Keywords: Vitamin D deficiency, Pseudohypoparathyroidism, Parathyroid hormone, Hypocalcemia, Ellsworth-Howard test

JOURNAL FREE ACCESS

2010 Volume 57 Issue 8 Pages 735-744

DOI https://doi.org/10.1507/endocrj.K10E-097

View "Advance Publication" version (May 25, 2010).

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Abstract

We report two patients with vitamin D deficiency due to unbalanced diet. The patients initially presented with severe hypocalcemia, normophosphatemia and markedly elevated serum PTH levels. Although nutritional vitamin D deficiency was suspected from their history of gastrointestinal problems and dietary restriction, we conducted Ellsworth- Howard test to exclude the possibility of pseudohypoparathyroidism (PHP). Both patients showed no incremental response of urinary phosphate excretion. However, the urinary cAMP response to exogenous PTH was different between the two. Case 1 showed a blunted response (5-fold and 1.54 μ mol/h increase) and case 2 showed a normal response (39-fold and 3.04 μ mol/h increase). According to the criteria of Ellsworth-Howard test, the data of case 1 was compatible with PHP type I, and of case 2 with PHP type II. The final diagnosis of vitamin D deficiency was established in both patients based on very low serum 25-hydroxyvitamin D levels (less than 5 ng/mL) and the effect of treatment. After calcium supplementation with or without vitamin D, their biochemical abnormalities disappeared. They maintained normocalcemia without medication after correction of their unbalanced diet. The present study indicated that patients with vitamin D deficiency occasionally showed biochemical findings suggestive of PHP and that such patients could exhibit not only PHP type II pattern of response to exogenous PTH but also of type I pattern. Thus our clinical observation suggests the complexity of PTH resistance in vitamin D deficiency and underscores the importance of diet to prevent the disorder.

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