A case report of pseudohypoparathyroidism type 1b caused by noval mutation of STX16

doi:10.16150/j.1671-2870.2026.03.014

Abstract

Abstract:

Pseudohypoparathyroidism (PHP) is a group of clinical syndromes caused by peripheral target tissue resistance to parathyroid hormone (PTH). Its main clinical features are hypocalcemia, hyperphosphatemia, and resulting tetany, convulsions, or epileptoid seizures. Patients with PHP 1b often present no specific signs and have diverse clinical manifestations, and if biochemical tests and PTH measurements are not performed in time, the diagnosis is likely to be delayed. This paper reports a 11-year-old boy with episodic convulsion as the main manifestation. The boy had low serum calcium and ionized calcium, significantly increased PTH, elevated serum phosphorus, and low urinary calcium and phosphorus. Genetic testing revealed heterozygous deletion of exons 5-7 of STX16 gene and loss of maternal methylation at GNAS-A/B. Parental testing for copy number changes and methylation status of STX16/GNAS-AS1/GNAS genes/regions showed no abnormalities. The patient was definitively diagnosed as a male pediatric case of autosomal dominant PHP 1b (AD-PHP 1b) caused by a new mutation of STX16. After oral treatment with calcitriol and calcium supplements, the patient's serum calcium gradually returned to normal, and no further convulsive seizures occurred. The patient is currently under follow-up. At present, no cases of male AD-PHP 1b caused by a new mutation of STX16 have been reported in China.

Key words: Pseudohypoparathyroidism type 1b, STX16 gene mutation, Autosomal dominant inheritance

CLC Number:

R581.2
R446

LI Siwen, DU Hongyu, CHEN Huaqin. A case report of pseudohypoparathyroidism type 1b caused by noval mutation of STX16[J]. Journal of Diagnostics Concepts & Practice, 2026, 25(03): 370-376.

Figures/Tables 8

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References 23

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时间	25-羟维生素D （ng/mL）	血钙（mmol/L）	血磷（mmol/L）	甲状旁腺素（pg/mL）
出院后1个月	32.32	1.62	2.74	-
出院后1.5个月	-	1.80	2.71	590.8
出院后2个月	37.96	1.99	2.57	-
出院后3个月	27.09	1.95	2.4	-
出院后3.5个月	33.28	1.89	2.28	-
出院后4个月	38.78	2.14	2.2	445.6
出院后4.5个月	35.46	2.32	2.26	-
出院后5个月	41.46	2.35	2.13	462.7
出院后7个月	48.22	2.30	1.83	-
出院后8个月	40.54	2.36	1.55	200
出院后13个月	41.18	2.15	1.72	643.9
出院后14个月	39.39	2.37	1.54	373.75
出院后20个月	39.58	2.48	1.59	82.6
出院后25个月	38.13	2.41	1.54	78.2