The clinical investigation of two cases of cutaneous skeletal hypophosphatemia syndrome and review of literature

doi:10.16150/j.1671-2870.2020.03.006

Abstract

Abstract:

Objective: To explore the clinical features, imaging manifestations, gene mutations and treatment response of 2 sporadic cases of cutaneous skeletal hypophosphatemia syndrome. Methods: The case history, clinical presentation and laboratory and imaging data were reviewed. The genomic DNA was extracted from peripheral blood and skin tissue of patients were sequenced by Sanger sequencing for detection of KRAS、NRAS and HRAS gene mutations. Results: Both patients had bone pain accompanied with progressive difficulty in movement, scoliosis, multiple fractures, and melanocytic nevi located in waist and hips. The laboratory investigation revealed decreased blood phosphorus level（0.44 mmol/L and 0.46 mmol/L） and elevated levels of alkaline phosphatase(ALP)（157 U/L and 277 U/L） and fibroblast growth factor 23(FGF-23)（57.0 ng/L and 118.5 ng/L）. The dual-energy X-ray absorption detector indicated a significant decrease in bone density. The symptoms were significantly improved after treatment with neutral phosphorus and vitamin D. No related gene mutation was identified. Conclusions: Cutaneous skeletal hypophosphatemia syndrome is a rare metabolic bone disease with unclear pathogenesis. Currently, the diagnosis still relies on characteristic clinical, laboratory and imaging manifestation. Identification of RAS gene mutations will help the establishment of the diagnosis.

Key words: Cutaneous nevi, hypophosphatemia, Skeletal dysplasia

CLC Number:

R589.5

LIU Li, WEI Zhe, LIN Xiaoyun, YUE Hua, ZHANG Zhenlin. The clinical investigation of two cases of cutaneous skeletal hypophosphatemia syndrome and review of literature[J]. Journal of Diagnostics Concepts & Practice, 2020, 19(03): 232-237.

Figures/Tables 3

References 35

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指标	例1	例2	正常参考范围
钙（mmol/L）	2.31	2.43	2.25~2.75
磷（mmol/L）	0.44	0.46	0.90~1.50
ALP（U/L）	157	277	15~112
β-CTX（ng/L）	426.50	445.00	25~29岁男性,415.00~551.00
			45~49岁女性,221.00~301.00
骨钙素（μg/L）	22.18	17.97	25~29岁男性17.19~19.77
			45~49岁女性,12.88~16.79
25-羟维生素D（μg/L）	24.84	22.71	>30.00
PTH（ng/L）	59.30	48.34	15.00~65.00
iFGF-23（ng/L）	57.0	118.5	33.9~51.8

指标	例1			例2
指标	入院	8个月	16个月	入院	20个月
腰椎BMD（g/cm²）	0.498	0.630	0.777	0.643	0.704
腰椎变化（%）	-	26.5	23.3	-	9.5
股骨颈BMD（g/cm²）	0.424	0.651	0.756	0.639	0.618
全髋BMD（g/cm²）	0.407	0.593	0.668	0.626	0.580
全髋变化（%）	-	53.5	16.1	-	-3.2