Etiological evaluation of idiopathic short stature

Introduction: Idiopathic short stature (ISS) constitutes nearly 80% of short stature cases. As the genetic analysis methods evolve, we are able to determine the underlying etiologies for the patients once diagnosed as ISS. Aim: This retrospective study aims to evaluate growth profiles of patients who were followed in İstanbul University İstanbul Medical Faculty Pediatric Endocrinology Department with ISS diagnosis, and also to investigate the cases with possible underlying etiologies for short stature. Materials and Methods: In our study, we included 78 patients who do not have a chronic disease that may affect their height status, are born with appropriate weight for gestational age, are not pre/post term, without malnutrition, and do not have growth hormone deficiency. Data are derived from patient files retrospectively. Patients anthropometric measurements at presentation, at beginning-peak-end of puberty, and at last visit, laboratory features, parental heights and family histories were recorded from the files. Patients were divided into two groups as familial and non-familial short stature for comparison. Results: In this study, among the patients who reached adult height(n:26) mean height SDS at presentation was found to be -2.69±0.66 and mean final height SDS was -1.79±0.47. Height SDS mean gain was 0.85±0.7 SD. Mean value for adult height SDS was 0.33±0.57 SD shorter than target height SDS. Familial short stature group followed their growth curve parallelly and reached their target height SDS, whereas non-familial short stature group did not reach their genetic potentials though they grew above -2 SD level. The mean age of puberty was 11.61±0.84 years for girls and 12.66±0.94 years for boys, and for both sexes it was delayed compared to the normal population. The height SDS at onset of puberty was found to be lower than the height SDS at presentation. Minimal dysmorphic features were detected in 19.2 % of the patients at presentation. For all groups sitting height was below -2 SDS at presentation with normal sitting height/height SDS. However 5 children had this value below -2SD. The mean Insulin Like Growth Factor 1 (IGF1) SDS level was 0.25±1.33. In 10.3% patients(n:8) IGF1 levels were above +2 SDS and 14.1% of the patients (n:11) had IGF1 levels below -2 SDS. Conclusion: Dysmorphic features that do not point to a specific syndrome, mild disturbances in body proportions and deviations in serum IGF1 levels might have etiological significance. Evaluation of growth profiles demonstrates the main pathological process takes place in prepubertal period. This proves the importance of regular growth monitoring. When diagnosed early, better adult height may be reached with the help of therapy in ISS. More research needs to be done on this subject. Keywords: Idiopathic short stature, puberty, growth profile, genetics, etiology