Children with short-limbed short stature in pediatric endocrinological services in Japan.
Short-limbed short stature is a heterogeneous condition that can reflect the effects of many diseases such as bone disorders, metabolic diseases, and multiple malformation syndromes.We conducted a questionnaire survey of council members of the Japanese Society of Pediatric Endocrinology and doctors of our affiliated hospitals in 2010 to investigate short-limbed short stature.Among 91 hospitals, responses were obtained from 61 hospitals (67% response rate). This study also examined data of 193 short-limbed short stature patients, among whom patients with FGFR3-related chondrodysplasia such as achondroplasia (n=109; 56.5%) are found the most frequently. Second to achondroplasia patients, hypochondroplasia patients (n=47; 24.4%) are the most frequently observed. Along with achondroplasia and hypochondroplasia patients, 31 patients with disorders of 13 other kinds and 6 undiagnosed patients were observed in this study. Genetic testing for diagnosis of hypochondroplasia is conducted for only 27.7% of all hypochondroplasia patients, although hypochondroplasia is a heterogeneous condition caused not only by FGFR3 gene mutation but also by other causes. We conducted a genetic analysis of 25 patients who had been clinically diagnosed as having 'hypochondroplasia'. In these patients, other diseases such as acromicric dysplasia, geleophysic dysplasia, and Aarskog-Scott syndrome were included in addition to 10 FGFR3-related hypochondroplasia patients.Clinical diagnosis of each disorder representing short-limbed short stature is difficult. Therefore, not only clinical diagnosis but also genetic diagnosis serves an important role in the diagnosis of short-limb short stature. Diagnostic strategies must be created for each disorder.