Prinster C, Del Maschio M, Beluffi G, Maghnie M, Weber G, Del Maschio A, Chiumello G
Laboratory of Paediatric Endocrinology, Scientific Institute H San Raffaele, University of Milan, Italy.
Pediatr Radiol. 2001 Mar;31(3):203-8. doi: 10.1007/s002470000398.
Hypochondroplasia is characterised by phenotypic and genetic heterogeneity. Differentiation from other conditions with disproportionate short stature is often difficult.
To determine the reliability of radiological interpretation in the diagnosis of hypochondroplasia and to evaluate the most typical skeletal abnormalities. These data were correlated with molecular findings.
We enrolled 21 patients with suspected hypochondroplasia based on the radiological criteria most often reported in the literature on this disease. Height, sitting height and head circumference were measured in all patients. Radiographs of the lumbar spine, left leg, pelvis and left hand were obtained. The presence of the N540K mutation in the fibroblast growth factor receptor 3 (FGFR3) gene was verified by restriction enzyme digestion. All radiographs which enabled the selection of patients were reviewed a second time by two paediatric radiologists in a blinded examination. Their results were compared.
Both radiologists confirmed the diagnosis in 10 out of 21 patients, while in the other 52% of cases they excluded the disease, were uncertain or they did not agree on the final interpretation of the data. The best agreement rate was obtained in the evaluation of the lumbar spine and the legs. The radiological features of the nine patients (43%) carrying the N540K substitution were not remarkably different from the ones reported in the patients without this mutation.
Our study shows that the crucial skeletal regions on which to focus the diagnosis of hypochondroplasia are the lumbar spine and legs, while the pelvis and hands seem to be less characteristic. To reduce the risk of misdiagnosis, accurate radiological and clinical evaluation is needed, especially in cases without a defined genetic defect.
软骨发育不全具有表型和遗传异质性。与其他身材比例不协调的矮小症鉴别往往困难。
确定放射学诊断软骨发育不全的可靠性，并评估最典型的骨骼异常。这些数据与分子学发现相关。
我们根据文献中最常报道的关于该病的放射学标准，纳入了21例疑似软骨发育不全的患者。测量了所有患者的身高、坐高和头围。获取了腰椎、左腿、骨盆和左手的X线片。通过限制性酶切验证成纤维细胞生长因子受体3（FGFR3）基因中N540K突变的存在。两位儿科放射科医生在盲法检查中对所有用于筛选患者的X线片进行了二次评估。比较他们的结果。
两位放射科医生在21例患者中确诊了10例，而在其他52%的病例中，他们排除了该病，或不确定，或对数据的最终解读不一致。在评估腰椎和腿部时一致性率最高。9例（43%）携带N540K替代突变的患者的放射学特征与未携带该突变的患者所报道的特征无明显差异。
我们的研究表明，软骨发育不全诊断中应重点关注的关键骨骼部位是腰椎和腿部，而骨盆和手部似乎特征性较差。为降低误诊风险，需要进行准确的放射学和临床评估，尤其是在没有明确基因缺陷的病例中。
