Screening for imprinting disorders in 58 patients with clinically diagnosed idiopathic short stature.

Objectives: Imprinted genes have important roles for normal growth and development. Imprinting disorders (IDs) such as Silver-Russell syndrome and Temple syndrome are rare diseases that typically cause short children born small for gestational age (SGA). However, some patients with short stature (SS) caused by IDs were born non-SGA. To date, the contribution of IDs to idiopathic short stature (ISS) has been poorly investigated. The aim of this study was to clarify the contribution of IDs to ISS. Methods: We conducted methylation analysis for 10 differentially methylated regions using pyrosequencing to detect known IDs in 58 patients (31 male and 27 female children, height standard deviation score -4.2 to -2.0) carrying a clinical diagnosis of ISS. Results: We identified no patient with IDs among these patients with ISS. Conclusions: These results indicate that IDs are rare in patients having ISS, and that imprinted genes affect fetal growth more than postnatal growth. Because patients with IDs born non-SGA usually have clinical features characteristic of each ID, in addition to SS, the patients with ISS as a clinical diagnosis may not be associated with IDs. It is unlikely that cases clinically diagnosed with ISS are caused by IDs leading to growth failure.