Etiology Of Growth Hormone Deficiency

Growth hormone deficiency ( GHD ) is characterised by short statue with serious psychosocial problem. It prevalence is estemated to be 1/4000-1/15000 live births. The resulting growth retardation is the manifestation of abnormal function of hypothalamo-pituitary GH axis. GHD is assumed to be devided into two catogories, so called idiopathic and organic GHD. In idiopathic form, as far as its etiology is concerned, two hypotheses have been put forward to explain its disease process, one is ' traumatic hypotheses', the other 'abnormal embryonic development'. In the current study, based on clinical case study, pituitary image analysis and molecular study of hGH-N gene, we set out to clarify some of the possible roles of the perinatal 'tramatic' factors and genetic abnormalities in the pathophysiolgy of idiopathic GHD.In the 548 cases of GHD recruited for study, 521 cases (95%) were idiopathic, with as small as 27 (5%) to be organic cases. It seemed that central nervous abnormalities played a major role in organic GHD, including central nervous infection, trauma, neoplasms, Langerhan's cell histiocytosis and hydrocephalus. In idiopathic GHD, perinatal insults were very common. At least 51.8% were affected with abnormal fetal presentation, 35.9% with birth asphyxia, which was in great contrast with normal population, in which only 3-4% is in the breech/foot presentation. Furthermore 21.3% of idiopathic GHD were also complicated with apparent central hypothyroidism. We devided the 521 idiopathic GHD into two groups, one with normal thyroid function, the other with hypothyroidism. We found that the incidence of abnormal pernatal history was significantly higher in patients with low thyroid function than those with normal thyroid function. Thus it is reasonable to deduce that perinatal insults could indeed affect pituitary endocrine funtion, especially in combined pituitary hormone deficiencies. Another phenomenon is that the incidences of breech/foot presentation and birth asphyxia were significantly higher in male than that in female patients. This suggested that the pathogenesis of GHD in male and female patients may have other differences.Based on MRI findings, 26 idiopathic GHD patients were devided into three group. Group 1 showed complete transection of pituitary stalk, group 2 with doubtful stalk transecton, and group 3 with normal stalk. Group1 and 2 comprised almost 81% of the 26 GHD. As reported in the literature, ectopic posterior lobe could be identified in 4 cases of group 1. In idiopathic GHD, depressed upper margin of pituitary gland and absence of normal posterior brightness were very common. MRI changes correlated closely with clinical pictures. The height SDS at initial visit...