Patients with sickle cell disease (SCD) frequently have bone disorders of multifactorial aetiology. We attempted to analyse the relationships between bone mineral density (BMD) on the one hand and auxologic parameters, degree of siderosis, function of the growth hormone (GH)/insulin-like growth factor-I (IGF-I)/IGF-binding protein 3 (IGFBP3) axis, and calcium-phosphate balance in 28 prepubertal children with SCD and 15 age-matched children with constitutional short stature (CSS). Children with SCD had significantly decreased BMD (77.9 +/- 11.9 per cent of normal BMD for age and sex) and circulating concentrations of IGF-I (91 +/- 31 ng/ml) and IGFBP3 (1.7 +/- 0.44 mg/l) compared with the control group (BMD = 93.5 +/- 8.2 per cent of normal BMD for age and sex, IGF-I = 221 +/- 48 ng/ml, and IGFBP3 = 2.3 +/- 0.34 mg/ml). GH response to provocation was defective (peak below 10 micrograms/l) in 40 per cent of children with SCD. Those with SCD with defective GH secretion had significantly lower circulating IGF-I concentration and BMD than those with normal GH secretion. Serum calcium, phosphate and alkaline phosphatase concentrations were normal in all children with SCD. BMD was correlated significantly with height, weight, and body mass index as well as with the circulating concentrations of IGF-I and IGFBP3. It is suggested that increasing the circulating IGF-I concentration, either through increasing the caloric intake of subjects and/or via GH/IGF-I therapy, may improve growth and bone mineralization in these patients.

6 Gibbons RJ, Suthers GK, Wilkie AOM, et al. X-linked a-thalassemia/mental retardation (ATR-X) syndrome: localisation to Xql 2-q21.31 by X inactivation and linkage analysis.

A study was conducted on growth hormone (GH) response to oral clonidine (0.15 mg/m2), GH and cortisol responses to i.m. glucagon (0.1 mg/kg), and glucose response to an oral load of glucose (1.75 g/kg). Measurements were made on the circulating concentrations of free thyroxine (FT4), thyroid stimulating hormone (TSH) and different growth parameters and CT sellar images in 25 GH deficient children (Peak GH response to clonidine and glucagon < 7 ug/ml), 15 growth retarded children (Ht < 5th percentile for age and gender) with sickle cell disease (SCD) and GH deficiency, 30 randomly selected children with normal variant short stature (NVSS) (HtSDS 2SD below the mean for age and gender with normal GH response to stimulation (> 10 ug/ml) and 20 age-matched normal children were evaluated. Out of the 25 children with GH deficiency, five had multiple pituitary hormonal deficiency (GH < TSH and/or ACTH. deficiencies), and 20 had isolated GH deficiency. Empty sella, either complete or partial, was detected in 9 out the 20 children with isolated GH deficiency (45%), 4 out of the 5 children with multiple pituitary deficiency (80%), all the children with SCD and GH deficiency (100%), 3 out of the 30 children with NVSS (10%) and in none of the normal children. The insulin-like growth factor-I (IGF-I) concentrations were significantly lower in the two groups of children with GH deficiency compared to those with NVSS. The height standard deviation scores (HTSDS) were significantly lower and the annual growth velocity was slower in children with idiopathic GH deficiency and empty sella compared to those with NVSS and those with empty sella associated with SCD. The bone age delay (yr) did not differ among the 3 groups of children with short stature. All children with isolated GH deficiency associated with empty sella had normal body mass indices (BMI), while all the children with SCD and empty sella had BMI below the 5th percentile for the corresponding age and gender. None of the children had glucose intolerance. In conclusion, children with growth retardation and abnormal hypothalamic pituitary functions have high incidence of empty sella. However, empty sella is detected in considerable number (10%) of short children with normal hypothalamic pituitary function.

Seven children, with a mean (SD) age of 4*6 (2.1) years, who as infants (21 (7.5) days) underwent near total (95-98%) pancreatectomy for persistent hyperinsulinaemic hypoglycaemia of infancy (PHHI) were studied. At birth all the infants were macrosomic. Four infants had been born after a difficult labour, of whom three had moderate birth asphyxia and respiratory distress. All had normal thyroid function. After surgery transient hyperglycaemia was manifest in six ofthe children and required insulin treatment for 5-8 (3.8) weeks, and transient hypoglycaemia was encountered in one child and responded well to increased carbohydrate intake and diazoxide for three weeks. Six of the children rapidly crossed down their length and weight centiles during the first year after surgery. At the end of the first year these children were at or below the 5th centile of height and weight for their age and gender. After a period of 4-6 (2.1) years, their mean (SD) height score was -2 57 (0.5), growth velocity 3-9 (0.75) cm/year, and growth velocity SD score -2-1 (0.55)1 these were

Serum growth hormone (GH), cortisol, free thyroxine (FT4), thyroid-stimulating hormone (TSH), and insulin like growth factor I (IGF-I) concentrations were measured in 15 children with sickle cell disease (SCD) together with their heights < 5th percentile for age and gender, and in 15 healthy age-matched children who had normal variant short stature (NVSS). GH response to an oral dose of clonidine (0.15 mg/m2) and cortisol response to ACTH stimulation were determined in the two groups. Children with SCD had significantly lower serum concentrations of IGF-I and decreased GH response to stimulation. Eight out of the 15 children with SCD did not mount an appropriate GH response to clonidine provocation (> 10 micrograms/l). CT scanning of the hypothalamic-pituitary area in those eight children with SCD revealed a partial or complete empty sella in all of them. It appears that defective GH release, and consequently low IGF-I production and slow growth velocity in children with SCD might be secondary to hypoxic-vascular insults to their hypothalamic-pituitary axis during one or more of the sickling episodes.