CLINICAL AND HORMONAL MILIEU OF 9 PATIENTS WITH PRIMARY GROWTH HORMONE INSENSITIVITY SYNDROME AND THEIR RESPONSE TO IGF-I GENERATION TEST

Primary growth hormone insensitivity syndrome (GHIS) is a rare entity which can be due to defects in growth hormone (GH) receptor that is called type 1 Laron syndrome (TILS) or post receptor defects (type 2 Laron syndrome ). The aim of study was determining the clinical and hormonal milieu of the patients with primary GHIS and their response to IGF-I (insulin like growth factor-I) generation test (IGT). GH, IGF-I, IGF-II, IGF binding protein 1 and 3 (BP-1 and BP-3), GH binding protein (GHBP) and anti-GH antibody were detected by ELISA and RIA methods. IGF-I and BP-3 were measured before and after IGT. Nine patients (8 males, 1 female) (mean age ± SD, 6.4 ± 5 years) with severe short stature and high GH level were studied. Height SDS was - 8.5 ± 2.6. In 7 patients GHBP was zero, IGF-I and BP-3 were low and did not increase after IGT, so they had TILS. Two brothers did not show the hormonal milieu of GH receptor defect, and were called non Laron syndrome (NLS). Birth weight in patients with TILS and NLS was 3.65 ± 0.2 Kg and 1.65 ± 0.2 Kg, respectively (P = 0.001). All of the patients had typical clinical feature of GH-deflciency, but nasal bridge depression and microphallus were not seen in NLS. GH treatment of NLS, normalized their growth velocity, but without catch up growth. In conclusion IGT can differentiate Laron syndrome from other types of short stature. GH and IGF-I of fetus have no role in intrauterine growth.