To determine the influence of hemoglobinopathy on growth and development, we examined the height, weight, and sexual maturation of 2115 patients 2 to 25 years old who had homozygous sickle-cell disease (SS), SC disease (SC), sickle beta+ thalassemia (S beta+), or sickle beta O thalassemia (S beta O). Using regression analysis of these cross-sectional data to generate growth and maturation curves for each hemoglobinopathy, we found that the curves for all hemoglobinopathy groups were significantly different from published norms for black subjects (P less than 0.001), and that subjects with SS and S beta O were consistently smaller and less sexually developed than those with SC and S beta+ (P less than 0.001). For both sexes and all hemoglobinopathies, low weight was more pronounced than short height and was most apparent in subjects over the age of seven. The median age of the female subjects who had attained at least Tanner Stage V was 17.3 years for those with SS, 17.2 years for S beta O, 16.0 years for SC, and 16.5 years for S beta+; among male subjects the corresponding values were 17.6, 18.8, 16.6, and 16.6 years. Discriminant analysis of menarche status, weight, age, and hemoglobinopathy revealed that the influences of age and weight on menarche were similar regardless of hemoglobinopathy. This relationship suggests a constitutional rather than a primary endocrinologic cause of sexual immaturity in patients with hemoglobinopathies.

The characteristic clinical heterogeneity of sickle cell anemia (HbSS) may be, in part, a result of its interactions with alpha-thalassemia. Although alpha-thalassemia clearly affects some hematologic features of HbSS, its role in modulating the vasoocclusive severity of disease is not clear. To further explore this relationship, we examined the incidence of painful episodes, acute chest syndrome, aseptic bone necrosis, and leg ulcers in 3 patient groups with sickle cell disease: (1) 2,147 patients over age 2 yr, stratified according to mean corpuscular volume (MCV); (2) 183 patients selected on the basis of microcytosis and elevated HbA2, on whom globin biosynthesis studies were done; and (3) 125 patients who had alpha-globin genotype assigned by restriction endonuclease gene mapping. When patients were stratified by MCV, there was a reciprocal relationship between HbA2 levels and MCV, reflecting the presence of patients with beta o and alpha- thalassemia in the low MCV groups. The erythrocyte indices and HbA2 levels in patients classified as HbSS-alpha-thalassemia, by either globin synthesis studies or gene mapping, were very similar to those previously reported by others. Neither microcytosis, beta o, or alpha- thalassemia appeared to provide any clear protection from the vasoocclusive complication evaluated, and the prevalence of aseptic necrosis was increased in patients with microcytosis over age 20 yr and in groups with alpha-thalassemia. The effects of a reduced MCV and mean corpuscular hemoglobin concentration (MCHC), of possible benefit by themselves, when accompanied by a reduction in hemolysis and rise in hemoglobin concentration, as in HbSS-alpha-thalassemia, may cause sufficient rise in blood viscosity in critical vascular beds to impair blood flow and negate any amelioration of vasoocclusive complications in HbSS.

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