Objective: To summarize the clinical manifestation and genetic characteristics of Chinese patients with achondroplasia (ACH) which is caused by pathogenic variants fibroblast growth factor receptor 3 (FGFR3) gene and establish the reference value of height centiles and height for age growth curve of patients for a more practical, simple and useful growth evaluation tool in China. Methods: Through a nationwide cross-sectional survey in China from July 2019 to January 2020 designed by Department of Pediatric Endocrinology and Genetics, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, 210 subjects (110 boys, 100 girls), who harbored the pathogenic variant of FGFR3 gene and were diagnosed with achondroplasia, were recruited. The clinical and genetic data of enrolled subjects were collected and analyzed to explore the clinical genetic characteristics of Chinese ACH patients. Furthermore, according to the data of height (body length under 2 years old) of boy and girl subjects aged 0-12 years, centiles and height for age growth curve of achondroplasia were calculated and established by LMS method respectively. Results: The characteristic clinical manifestations of 210 Chinese patients (0-14 years old) were disproportionate short stature (206/210, 98.1%), macrocephaly and characteristic facial features (205/210, 97.6%), trident configuration of the hands (191/210, 90.9%), limbs deformity (156/210, 74.3%), together with normal intelligence. Up to 81.9% (172/210) of patients have different complications, and the kyphosis (121/210, 57.6%) and narrow thoracic (79/210, 37.6%) are common complications. Besides, up to 98.6% (207/210) of patients harbored hotspot variants of FGFR3 gene which cause G380R amino acid substitutions. It is notable that the growth pattern of boy and girl patients (0-12 years old) is obviously different from the normal children (t=9.849, 9.596, P<0.01) respectively. The height different between ACH patients and normal children gradually widened with age. The average height of the boy (49.2 cm) and girl patients(48.4 cm) of achondroplasia at birth was -1.22 s and -2 s, however, at the age of twelve, the average height of the boy(113.7 cm) and girl patients(112.4 cm) of achondroplasia was -5.23 s and -6.15 s compared to currently standard reference height for age growth curve of normal children in China, respectively. Conclusions: The results of our study demonstrated that in China disproportionate short stature, macrocephaly and characteristic facial features were typical manifestations of ACH patients, and that up to 98.6% of patients harbored hotspot variants of FGFR3 gene. In addition, the reference value of height centiles and height for age growth curve of ACH patients we establish will be a valuable tool for evaluating the growth pattern, monitoring factors affecting growth, estimating ultimate height, and assessing the curative effect of growth-promoting treatments in Chinese patients with achondroplasia.
目的： 总结携带成纤维细胞生长因子受体3（FGFR3）基因变异的中国软骨发育不全（ACH）患儿的临床表现及遗传学特征，拟合中国ACH患儿身高生长百分位参照值及身高与年龄生长曲线，为中国ACH患儿提供更为实用的生长评价工具。 方法： 横断面研究。于2019年7月至2020年1月由上海交通大学医学院附属新华医院儿内分泌/遗传科组织开展，在全国范围内入组210例FGFR3基因检测确诊的ACH患儿（男110例、女100例），收集患儿临床资料及身高数据；分析中国ACH人群的临床特征及遗传学特点并依据0~12岁患儿身高（2岁以下测量身长）测量数据，应用LMS方法对数据进行拟合修匀，分别获得所需要的百分位并绘制ACH患儿身高与年龄生长曲线图。 结果： 210例中国ACH患儿（0~14岁）主要临床表现典型包括非匀称性矮小206例（98.1%），手指短小且呈"三叉戟"样191例（90.9%），小腿弯曲156例（74.3%），头颅大且伴前额突出205例（97.6%）;210例患儿智力及体力发育均良好；172例（81.9%）ACH患儿发生并发症,主要的并发症是脊柱畸形121例（70.3%）和胸廓窄79例（45.9%）。高达98.6%（207/210）的患儿携带FGFR3杂合热点变异（第1138位核苷酸点突变）导致发生的G380R氨基酸替换。ACH男、女患儿生长模式与正常儿童群体中观察到的生长模式存在明显不同（t=9.849、9.596,P均<0.01）；出生时患儿的平均身长（男49.2 cm，女48.4 cm）分别为正常儿童的-1.22 s和-2 s，随着年龄增长ACH患儿与正常儿童的身高差距逐渐拉大，至12岁时患儿平均身高（男113.7 cm，女112.4 cm）分别为正常儿童标准的-5.23 s和-6.15 s。 结论： 中国FGFR3基因变异致ACH患儿的临床表现典型主要为非匀称性矮小和颅面部发育异常、遗传特征主要为携带G380R热点变异且首次拟合中国0~12岁ACH患儿身高与年龄生长曲线图及其身高百分位数对于评估患儿的生长情况、监测可能影响其生长的因素、估计其最终身高以及评估促生长治疗的疗效提供实用的生长评价工具。.
Keywords: Achondroplasia; Developmental disabilities; Dwarfism; Growth charts.