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Wu J, Wang M, Jiao Z, Dou B, Li B, Zhang J, Zhang H, Sun Y, Tu X, Kong X, Bai Y. Novel Loss-of-Function Mutations in NPR2 Cause Acromesomelic Dysplasia, Maroteaux Type. Front Genet 2022; 13:823861. [PMID: 35368703 PMCID: PMC8967736 DOI: 10.3389/fgene.2022.823861] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Accepted: 02/18/2022] [Indexed: 11/13/2022] Open
Abstract
Acromesomelic dysplasia, Maroteaux type (AMDM) is a rare skeletal dysplasia characterized by severe disproportionate short stature, short hands and feet, normal intelligence, and facial dysmorphism. Homozygous or compound heterozygous mutations in the natriuretic peptide receptor 2 (NPR2) gene produce growth-restricted phenotypes. The current study was designed to identify and characterize NPR2 loss-of-function mutations in patients with AMDM and to explore therapeutic responses to recombinant growth hormone (rhGH). NPR2 was sequenced in two Chinese patients with AMDM via next generation sequencing, and in silico structural analysis or transcript analysis of two novel variants was performed to examine putative protein changes. rhGH treatment was started for patient 1. Three NPR2 mutations were identified in two unrelated cases: two compound heterozygous mutations c.1112G>A p.(Arg371Gln) and c.2887+2T>C in patient 1 and a homozygous mutation c.329G>A p.(Arg110His) in patient 2, yielding distinct phenotypes. RNA extracted from peripheral blood cells of patient 1 showed alternatively spliced transcripts not present in control cells. Homology modeling analyses suggested that the c.1112G>A p.(Arg371Gln) mutation disrupted the binding of NPR-B homodimer to its ligand (C-type natriuretic peptide) in the extracellular domain as a result of global allosteric effects on homodimer formation. Thus, c.2887+2T>C and c.1112G>A p.(Arg371Gln) in NPR2 were loss-of-function mutations. Furthermore, rhGH therapy in patient 1 increased the patient’s height by 0.6SDS over 15 months without adversely affecting the trunk-leg proportion. The short-term growth-promoting effect was equivalent to that reported for idiopathic short stature. Overall, our findings broadened the genotypic spectrum of NPR2 mutations in individuals with AMDM and provided insights into the efficacy of rhGH in these patients.
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Affiliation(s)
- Jing Wu
- Department of Pediatrics, First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Mengru Wang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology and Center for Human Genome Research, Huazhong University of Science and Technology, Wuhan, China
| | - Zhouyang Jiao
- Department of Vascular and Endovascular Surgery, First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Binghua Dou
- Department of Pediatrics, First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Bo Li
- Department of Physiology and Neurobiology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Jianjiang Zhang
- Department of Pediatrics, First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Haohao Zhang
- Department of Endocrinology, First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Yue Sun
- Genetic and Prenatal Diagnosis Center, Department of Obstetrics and Gynecology, First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Xin Tu
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology and Center for Human Genome Research, Huazhong University of Science and Technology, Wuhan, China
| | - Xiangdong Kong
- Genetic and Prenatal Diagnosis Center, Department of Obstetrics and Gynecology, First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
- *Correspondence: Ying Bai, ; Xiangdong Kong,
| | - Ying Bai
- Genetic and Prenatal Diagnosis Center, Department of Obstetrics and Gynecology, First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
- *Correspondence: Ying Bai, ; Xiangdong Kong,
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Kılıç E, Çavdarlı B, Büyükyılmaz G, Kılıç M. Acromesomelic dysplasia-Maroteaux type, nine patients with two novel NPR2 variants. J Pediatr Endocrinol Metab 2021; 34:1115-1121. [PMID: 34162036 DOI: 10.1515/jpem-2021-0055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Accepted: 05/25/2021] [Indexed: 11/15/2022]
Abstract
OBJECTIVES Acromesomelic dysplasia, type Maroteaux, is an autosomal recessive skeletal dysplasia caused by biallelic loss of function variations of NPR2, which encodes a cartilage regulator C-type natriuretic peptide receptor B. NPR2 variations impair skeletal growth. It is a rare type of dwarfism characterized by shortening of the middle and distal segments of the limbs with spondylar dysplasia. METHODS We performed detailed clinical and radiological evaluation and sequence analysis for NPR2. RESULTS Herein, we report nine patients from eight families with two novel NPR2 pathogenic variants. CONCLUSIONS This study describes typical clinical phenotypes of Maroteaux type acromesomelic dysplasia, and enriches the variant spectrum of NPR2 by reporting one nonsense and one missense novel variant. We emphasize the importance of detailed clinical evaluation before genetic testing in diagnosing rare skeletal disorders.
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Affiliation(s)
- Esra Kılıç
- Department of Pediatric Genetics, University of Health Sciences, Ankara City Hospital, Ankara, Turkey.,Üniversiteler Mahallesi, 1604, Cadde No: 9, 06800 Çankaya/Ankara, Turkey
| | - Büşranur Çavdarlı
- Department of Medical Genetics, Ankara City Hospital, Ankara, Turkey
| | - Gönül Büyükyılmaz
- Department of Pediatric Endocrinology, Ankara City Hospital, Ankara, Turkey
| | - Mustafa Kılıç
- Department of Pediatric Metabolism, Sami Ulus Children Hospital, Ankara, Turkey
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