Endocrine complications of thalassemia

Iron overload disorders: Growth and gonadal dysfunction in childhood and adolescence

Hemochromatosis (HC) is characterized by the progressive accumulation of iron in the body, resulting in organ damage. Endocrine complications are particularly common, especially when the condition manifests in childhood or adolescence, when HC can adversely affect linear growth or pubertal development, with significant repercussions on quality of life even into adulthood. Therefore, a timely and accurate diagnosis of these disorders is mandatory, but sometimes complex for hematologists without endocrinological support. This is a narrative review focused on puberty and growth disorders during infancy and adolescence aiming to offer guidance for diagnosis, treatment, and proper follow-up. Additionally, it aims to highlight gaps in the existing literature and emphasizes the importance of collaboration among specialists, which is essential in the era of precision medicine.

Haemoglobinopathies and other rare anemias in Spain: ten years of a nationwide registry (REHem-AR)

REHem-AR was created in 2013. The progressive implementation of neonatal screening for haemoglobinopathies in Spanish autonomous communities where the registry had not been implemented, as well as the addition of new centres during this period, has considerably increased the sample of patients covered. In this study, we update our previous publication in this area, after a follow-up of more than 5 years. An observational, descriptive, multicentre and ambispective study of adult and paediatric patients with haemoglobinopathies and rare anaemias registered in REHem was performed. The data are from a cross-sectional analysis performed on 1 June, 2023. The study population comprised 1,756 patients, of whom 1,317 had SCD, 214 had thalassaemia and 224 were diagnosed with another condition. Slightly more than one third of SCD patients (37%) were diagnosed based on neonatal bloodspot screening, and the mean age at diagnosis was 2.5 years; 71% of thalassaemia patients were diagnosed based on the presence of anaemia. Vaso-occlusive crisis and acute chest syndrome continue to be the most frequent complications in SCD. HSCT was performed in 83 patients with SCD and in 50 patients with thalassaemia. Since the previous publication, REHem-AR has grown in size by more than 500 cases. SCD and TM are less frequent in Spain than in other European countries, although the data show that rare anaemias are frequent within rare diseases. REHem-AR constitutes an important structure for following the natural history of rare anaemias and enables us to calculate investment needs for current and future treatments.

Magnitude of Bone Disease in Transfusion-Dependent and Non-Transfusion-Dependent β-Thalassemia Patients

Introduction β-Thalassemia is a common inherited disease in the northern part of Iraq. A considerable number of transfusion-dependent (TDT) and non-transfusion-dependent (NTDT) β-thalassemia patients suffer bone problems. The objective of this study was to evaluate the degree of bone disease in the TDT and NTDT patients using a dual-energy X-ray absorptiometry (DEXA) scan. Patients and methods In this study, 53 TDT and 20 NTDT patients aged ≥10 years were enrolled. Their bone status was assessed using the DEXA scan at the lumbar spine (L1-L4) and femoral neck. The effect of physical, biochemical, and hormonal characteristics on the bone mineral density (BMD) parameters was evaluated. The value of the BMD Z-score was the measure to decide on the magnitude of bone disease. Results and discussion The mean age of the enrolled patients was 24.1 years. The BMD Z-score values were significantly lower among the TDT patients at the lumbar spine and femoral neck (BMD Z-score: -2.05 and -1.51 versus -2.29 and -0.71; p=0.044 and 0.009, respectively). The proportion of osteoporosis at the lumbar spine was significantly higher in the TDT group than in the NTDT group (69.8% versus 40%; p <0.001). The BMD Z-score correlated significantly with patient BMI and parathyroid hormone (PTH) level in both the TDT and NTDT groups. No correlation was found with age, hemoglobin (Hb), and serum levels of calcium, vitamin D, ferritin, phosphorus, and alkaline phosphatase (ALP). Conclusions Impaired bone density was encountered at high proportions in our thalassemia patients. TDT patients suffered more severe bone disease than NTDT patients.

A Systematic Review and Meta-Analysis of Stature Growth Complications in β-thalassemia Major Patients

Background

Blood transfusion is a traditional treatment for β-thalassemia (β-thal) that improves the patients' anemia and lifespan, but it may lead to iron overload in parenchymal tissue organs and endocrine glands that cause their dysfunctions as the iron regulatory system can't excrete excess iron from the bloodstream.

Objective

To evaluate the prevalence of iron-related complications (short stature, growth retardation, and growth hormone deficiency) in β-thalassemia major (βTM) patients.

Methods

We performed an electronic search in PubMed, Scopus, and Web of Sciences to evaluate the prevalence of growth hormone impairment in β-thalassemia major (βTM) patients worldwide. Qualities of eligible studies were assessed by the Joanna Briggs Institute checklist for the prevalence study. We used Comprehensive Meta-Analysis (Version 2) to calculate the event rate with 95% CIs, using a random-effects model for all analyses.

Findings

Seventy-four studies were included from five continents between 1978 and 2019; 70.27% (Asia), 16.21% (Europe), 6.75% (Africa), 2.70% (America), 1.35% (Oceania), and 2.70% (Multicenter). The overall mean age of the participants was about 14 years. The pooled prevalence of short stature (ST) was 48.9% (95% CI 35.3-62.6) and in male was higher than female (61.9%, 95% CI 53.4-69.7 vs. 50.9%, CI 41.8-59.9). The pooled prevalence of growth retardation (GR) was 41.1% and in male was higher than in female (51.6%, 95% CI 17.8-84 vs. 33.1%, CI 9.4-70.2). The pooled prevalence of growth hormone deficiency (GHD) was 26.6% (95% CI 16-40.8).

Conclusion

Our study revealed that near half of thalassemia patients suffer from growth impairments. However, regular evaluation of serum ferritin levels, close monitoring in a proper institute, suitable and acceptable treatment methods besides regular chelation therapy could significantly reduce the patients' complications.

Evaluation of the vitamin D and biomedical statuses of young children with β-thalassemia major at a single center in southern China

BACKGROUND

In young children, β-thalassemia major (β-TM) is associated with potentially severe clinical characteristics, including poor growth, feeding difficulties, hepatosplenomegaly, bone metabolic disorders, and skeletal abnormalities.

METHODS

In this study, we reviewed the demographic and clinical characteristics (e.g., age, sex, duration of blood transfusion and chelating therapy, and vitamin supplementation) and serum biomarker levels (e.g., iron accumulation, bone metabolism, liver, kidney, and thyroid function markers) of 32 patients that received regular blood transfusion at a single center in southern China with the aim of stratifying the risk of severe complications such as osteopenia, endocrinopathies, and multi-organ failures.

RESULTS

Although all patients exhibited moderately to strongly elevated serum ferritin levels, this biomarker was significantly higher in children older than ≥5 years, compared to younger children (*p < 0.05, 1512 ± 192.6 vs. 2337 ± 299.8 ng/ml, Mann-Whitney U test). Older children had a significantly lower 25-hydroxy vitamin D3 (25(OH)D₃) level, compared to younger children (**p < 0.01, 34.25 ± 11.06 vs. 23.05 ± 9.95 ng/ml, Mann-Whitney U test). No age-related differences were observed in serum calcium, phosphorus, and PTH levels. Regarding liver function, the serum alanine aminotransferase (ALT) level was significantly increased in children older than ≥5 years, compared to younger children (*p < 0.05, 19.17 ± 2.44 vs. 43.45 ± 9.82I U/ml, Mann-Whitney U test). However, no age-related differences were observed in the serum levels of other liver or kidney and thyroid biomarkers.

CONCLUSIONS

Our results suggest that in older children, hepatic iron overload may be associated with a low serum concentration of 25(OH)D₃, an indicator of vitamin D deficiency and altered bone metabolism. Iron accumulation may also be associated with a higher concentration of ALT, a sensitive marker of liver malfunction. These findings may provide important clinical indications of the need for intervention to prevent severe complications in children with β thalassemia.

Intestinal calcium transport and its regulation in thalassemia: interaction between calcium and iron metabolism

Osteoporosis and derangement of calcium homeostasis are common complications of thalassemia. Despite being an important process for bone and calcium metabolism, little is known about intestinal calcium transport in thalassemia. Recent reports of decreases in both intestinal calcium transport and bone mineral density in thalassemic patients and animal models suggested that defective calcium absorption might be a cause of thalassemic bone disorder. Herein, the possible mechanisms associated with intestinal calcium malabsorption in thalassemia are discussed. This includes alterations in the calcium transporters and hormonal controls of the transcellular and paracellular intestinal transport systems in thalassemia. In addition, the effects of iron overload on intestinal calcium absorption, and the reciprocal interaction between iron and calcium transport in thalassemia are elaborated. Understanding the mechanisms underlining calcium malabsorption in thalassemia would lead to development of therapeutic agents and mineral supplements that restore calcium absorption as well as prevent osteoporosis in thalassemic patients.

Endocrine Complications

More than five decades ago, thalassemia major (TM) was fatal in the first decade of life [...]

Hypothyroidism associated with parathyroid disorders

Hypothyroidism may occur in association with congenital parathyroid disorders determining parathyroid hormone insufficiency, which is characterized by hypocalcemia and concomitant inappropriately low secretion of parathormone (PTH). The association is often due to loss of function of genes common to thyroid and parathyroid glands embryonic development. Hypothyroidism associated with hypoparathyroidism is generally mild and not associated with goiter; moreover, it is usually part of a multisystemic involvement not restricted to endocrine function as occurs in patients with 22q11 microdeletion/DiGeorge syndrome, the most frequent disorders. Hypothyroidism and hypoparathyroidism may also follow endocrine glands' damages due to autoimmunity or chronic iron overload in thalassemic disorders, both genetically determined conditions. Finally, besides PTH deficiency, hypocalcemia can be due to PTH resistance in pseudohypoparathyroidism; when hormone resistance is generalized, patients can suffer from hypothyroidism due to TSH resistance. In evaluating patients with hypothyroidism and hypocalcemia, physical examination and clinical history are essential to drive the diagnostic process, while routine genetic screening is not recommended.

Review and Recommendations on Management of Adult Female Thalassemia Patients with Hypogonadism based on Literature Review and Experience of ICET-A Network Specialists

BACKGROUND

Multi-transfused thalassemia major (TM) patients frequently develop severe endocrine complications, mainly due to iron overload, anemia, and chronic liver disease, which require prompt diagnosis, treatment and follow-up by specialists. The most common endocrine complication documented is hypogonadotropic hypogonadism which increases with age and associated comorbidities. It is thus important for physicians to have a clear understanding of the pathophysiology and management of this disorder. Also to be aware of the side effects, contraindications and monitoring of sex steroid therapy. In this paper, practical ICET-A recommendations for the management of hypogonadism in adult females with TM are addressed.

METHODS

In March 2015, the Coordinator of the International Network of Clinicians for Endocrinopathies in Thalassemia and Adolescent Medicine (ICET-A) conducted a two-step survey to assess the attitudes and practices of doctors in the ICET-A network taking care of adult female TM patients with hypogonadism. They were clinically characterized by the absence of pubertal development or discontinuation or regression of the maturation of secondary sex characteristics, and biochemically by persistent low FSH, LH and estradiol levels. Recently a supplementary survey on adult female hypogonadism in TM was undertaken within the ICET-A network.

RESULTS

The completed questionnaires were returned by 16 of 27 specialists (59.2%) following 590 female TM patients over the age of 18 years; 315 patients (53.3%) had hypogonadism, and only 245 (74.6%) were on hormone replacement therapy (HRT). Contraceptive oral pills (COC) were the first treatment choice in 11 centers (68.7%). A wide range of COCs was used with different progestin contents. In general, the patients' compliance to treatment was reported as good in 81.2 % of centers. The frequency of required tests for follow-up HRT, in addition to the regular check-up for thalassemia, was variable in the participating centers.

CONCLUSIONS

Doctors taking care of TM patients should have sound knowledge of the pathophysiology of hypogonadism in adult females with TM. They should know the potential effects of HRT including advantages and disadvantages of estrogen and progestins. Moreover, they should keep in consideration the emotional needs of these patients dreaming of attaining a full pubertal development.

Bone turnover and mineral density in adult thalassemic patients: relationships with growth hormone secretory status and circulating somatomedins

Previous evidence supports a role for growth hormone (GH)-insulin-like growth factor (IGF)-I deficiency in the pathophysiology of osteopenia/osteoporosis in adult thalassemia. Moreover, serum IGF-II has never been studied in this clinical condition. Thus, we elected to study the GH secretory status and the levels of circulating somatomedins, correlating these parameters with bone mineral density (BMD) and biochemical markers of bone turnover. A hundred and thirty-nine normal weight adult thalassemic patients (72 men and 67 women) were studied. Lumbar and femoral neck BMD were measured in 106/139 patients. Sixty-eight patients underwent growth hormone releasing hormone plus arginine testing. Measurement of baseline IGF-I and IGF-II was performed in all patients, while osteocalcin, C-terminal telopeptide of type I collagen (CTx), and urinary cross-linked N-telopeptides of type I collagen (NTx) were assayed in 95 of them. Femoral and lumbar osteoporosis/Z score below the expected range for age were documented in 61.3 and in 56.6 % of patients, respectively. Severe GH deficiency (GHD) was demonstrated in 27.9 % of cases, whereas IGF-I SDS was low in 86.3 %. No thalassemic patients displayed circulating levels of IGF-II below the reference range. GH peaks were positively correlated with femoral, but not lumbar, Z score. No correlations were found between GH peaks and osteocalcin, CTx and NTx. GH peaks were positively correlated with IGF-I values, which in their turn displayed a positive correlation with osteocalcin, CTx, and NTx. No correlations emerged between IGF-I values and either femoral or lumbar Z scores. No correlations were found between IGF-II and any of the following parameters: GH peaks, osteocalcin, CTx, NTx, femoral Z score, and lumbar Z score. Our study, besides providing for the first time evidence of a normal IGF-II production in thalassemia, contributes to a better understanding of the involvement of the somatotropin-somatomedin axis in the pathophysiology of bone demineralization in this disease. In particular, the contribution of GHD to femoral osteoporosis appears to be likely mediated by locally produced rather than circulating IGF-I.

The Feasibility of Magnetic Resonance Imaging for Quantification of Liver, Pancreas, Spleen, Vertebral Bone Marrow, and Renal Cortex R2* and Proton Density Fat Fraction in Transfusion-Related Iron Overload

OBJECTIVE

We aimed to evaluate the feasibility of quantification of liver, pancreas, spleen, vertebral bone marrow, and renal cortex R2* and magnetic resonance imaging-proton density fat fraction (MRI-PDFF) and to evaluate the correlations among them in patients with transfusion-related iron overload.

MATERIALS AND METHODS

A total of 9 patients (5 boys, 4 girls) who were referred to our clinic with suspicion of hepatic iron overload were included in this study. All patients underwent T1-independent volumetric multi-echo gradient-echo imaging with T2* correction and spectral fat modeling. MRI examinations were performed on a 1.5 T MRI system.

RESULTS

All patients had hepatic iron overload. Severe hepatic iron overload was recorded in 5/9 patients (56%), and when we evaluated the PDFF maps of these patients, we observed an extensive patchy artifact in the liver in 4 of 5 patients (R2* greater than 671 Hz). When we performed MRI-PDFF measurements despite these artifacts, we observed artifactual high MRI-PDFF values. There was a close correlation between average pancreas R2* and average pancreas MRI-PDFF (p=0.003, r=0.860). There was a significant correlation between liver R2* and average pancreas R2* (p=0.021, r=0.747), liver R2* and renal cortex R2* (p=0.020, r=0.750), and average pancreas R2* and renal cortex R2* (p=0.003, r=0.858). There was a significant negative correlation between vertebral bone marrow R2* and age (p=0.018, r=-0.759).

CONCLUSION

High iron content of the liver, especially with a T2* value shorter than the first echo time can spoil the efficacy of PDFF calculation. Fat deposition in the pancreas is accompanied by pancreatic iron overload. There is a significant correlation between hepatic siderosis and pancreatic siderosis. Renal cortical and pancreatic siderosis are correlated, too.

Association between levels of serum ferritin and bone mineral density in Korean premenopausal and postmenopausal women: KNHANES 2008-2010

BACKGROUND

As women go through menopause, serum estrogen decreases and ferritin increases. Decreased serum estrogen is well known to cause detrimental effects on bone health; however, data on the associations of serum ferritin with BMD before and after menopause are still lacking. Therefore, this study aimed to investigate the association between serum ferritin levels and BMD in premenopausal and postmenopausal Korean women.

METHODS

This study was performed using data from the 2008-2010 Korean National Health and Nutrition Examination Survey, including 7300 women (4229 premenopausal and 3071 postmenopausal). BMD was measured using dual X-ray absorptiometry at the femur and the lumbar spine, and serum ferritin levels were measured by chemiluminescent immunoassay.

RESULTS

Median serum ferritin levels in postmenopausal women were higher than those in premenopausal women despite the same age ranges. Serum ferritin levels were only significantly correlated with BMD on the lumbar spine (β = -0.189, p-value = 0.005) in premenopausal women after adjusting confounding factors. Additionally, BMD on the lumbar spine had tended to decrease as serum ferritin quartiles increase (P for trend = 0.035) in premenopausal women after adjusting confounding factors. On the other hand, there were no significant associations between serum ferritin levels and BMD on the total femur and, femur neck in premenopausal women, and BMD on the total femur, femur neck, and lumbar spine in postmenopausal women.

CONCLUSION

Increased serum ferritin levels were significantly associated with BMD in premenopausal women, particularly on the lumbar spine, but not in postmenopausal women.

Failure of puberty in Egyptian beta thalassemic patients: Experience in north east region—Dakahlia province

BACKGROUND

Endocrine complications in thalassemia major (TM) are classically considered to be the result of iron deposition in the endocrine glands. Hypogonadotropic hypogonadism, which still remains the commonest endocrinopathy in patients with TM, has been proven to be the result of hemosiderosis of the gonadotroph cells of the pituitary gland.

THE AIM OF THE STUDY

To evaluate the prevalence of delayed puberty and hypogonadotropic hypogonadism in transfusion-dependent patients with beta-TM.

PATIENT AND METHODS

Growth and sexual development of 40 patients with TM (20 males, 20 females) aged 12-22 years were evaluated. Thirty healthy individuals aged 12-20 years served as a control group. The following parameters were measured in every patient: age, sex, height, weight, body mass index (BMI) and Tanner's pubertal staging. For all patients, the following investigations were done: ophthalmological evaluation, audiograms, skeletal survey, echocardiography, serum ferritin, liver function tests, hepatitis profile, serum calcium, phosphorus and blood sugar. Thyroid, parathyroid hormones, serum follicle stimulating hormone (FSH), luteinizing hormone (LH), testosterone (T) and estradiol (E2) hormone were also measured.

RESULTS

Failure of puberty was present in 80% of boys and 75% of girls aged 12-22 years. Gonadotropin insufficiency was found in most of the patients with lack of puberty. Arrested puberty was noted in five boys (25%) and six girls (30%). Ten girls (50%) did not menstruate, two (10%) had oligomenorrhea, one (5%) had irregular menstrual cycles and two (10%) developed secondary amenorrhea. Using univariate analyses and stepwise logistic regression analysis after adjustment for confounding factors, serum ferritin at the time of the study was identified as an independent risk factor for hypogonadotropic hypogonadism, with an odds ratio of 28.40 (95% confidence interval 3.25-245.15), P = 0.003 with a B value of 3.24 (standard error, 1.12).

CONCLUSIONS

We conclude that failure of puberty is common in our thalassemic patients which necessitates newer protocols of treatment, correct blood transfusion and chelation therapy.

Ineffective erythropoiesis in β -thalassemia

In humans, β-thalassemia dyserythropoiesis is characterized by expansion of early erythroid precursors and erythroid progenitors and then ineffective erythropoiesis. This ineffective erythropoiesis is defined as a suboptimal production of mature erythrocytes originating from a proliferating pool of immature erythroblasts. It is characterized by (1) accelerated erythroid differentiation, (2) maturation blockade at the polychromatophilic stage, and (3) death of erythroid precursors. Despite extensive knowledge of molecular defects causing β-thalassemia, less is known about the mechanisms responsible for ineffective erythropoiesis. In this paper, we will focus on the underlying mechanisms leading to premature death of thalassemic erythroid precursors in the bone marrow.

Gonadal dysfunction and pelvic sonographic findings in females with thalassaemia major

OBJECTIVE

To investigate pubertal and menstrual problems and evaluate pelvic sonographic findings in patients with beta-thalassaemia major.

MATERIAL AND METHODS

Twenty-five female patients followed for thalassaemia major constituted the study population. Sexual maturation and hormonal status were assessed. Pubertal and menstrual problems were investigated.

RESULTS

There was one patient with delayed puberty and five patients with arrested puberty. Mean ferritin level in this group of patients was slightly but not significantly higher than patients with normal pubertal maturation (2620 +/- 994 ng/ml vs. 2409 +/- 1348 ng/ml, p > 0.05). There were 10 patients with primary amenorrhoea, three with secondary amenorrhoea, five with oligomenorrhoea and irregular menstruation and one with regular menstruation. Compared to menstruating patients, the mean uterine size was smaller (4.1 +/- 3.5 cm(3) vs. 52.8 +/- 14.5 cm(3)) in all patients with delayed and arrested puberty (p < 0.05). Ten patients were taking hormone replacement therapy (HRT). The mean uterine size in these patients was larger than that in patients with amenorrhoea who were not taking HRT, but smaller than that in menstruating patients (9.1 +/- 15.9 cm(3), 2.7 +/- 1.3 cm(3) and 52.8 +/- 14.5 cm(3), respectively) (p < 0.05).

CONCLUSION

Thalassaemia major has important side effects on the hypothaloma-pituitary-gonadal axis resulting in pubertal and menstrual abnormalities. HRT should be given to provide normal sexual maturation in these patients.

Thalassaemia and aberrations of growth and puberty

Endocrine dysfunction in Thalassaemia major (TM) is a common and disturbing complication, which requires prompt recognition and treatment. The contribution of the underlying molecular defect in TM to the development of endocrinopathies is significant because the patients with the more severe genetic defects have a greater rate of iron loading through higher red cell consumption. TM patients frequently present delay of growth and puberty with reduction of final height. The pathogenesis of growth failure is multifactorial and is mainly due to chronic anemia and hypoxia, chronic liver disease, zinc and folic acid deficiency, iron overload, intensive use of chelating agents, emotional factors, and endocrinopathies (hypogonadism, delayed puberty, hypothyroidism) and GH-IGF-1 axis dysregulation. Although appropriate iron chelation therapy can improve growth and development, TM children and adolescents treated intensively with desferrioxamine remain short as well, showing body disproportion between the upper and lower body segment. Body disproportion is independent of pubertal or prepubertal period of greater height gain. Treatment with recombinant GH (rhGH) is recommended when GH deficiency is established, and even so, the therapeutic response is often non satisfactory. Growth acceleration is mostly promoted with sex steroids in children with associated pubertal delay. Sexual complications in TM, which include Delayed Puberty, Arrested Puberty and Hypogonadism, present the commonest endocrine complication. Iron deposition on gonadotroph cells of the pituitary leads to disruption of gonadotrophin production which is proven by the poor response of FSH and LH to GnRH stimulation. In the majority of patients gonadal function is normal as most women with Amenorrhea are capable of achieving pregnancy with hormonal treatment and similarly men with azoospermia become fathers. Secondary Hypogonadism appears later in life, and is manifested in women as Secondary Amenorrhea and in men as decline in sexual drive and azzoospermia. The damage to the hypothalamus and pituitary is progressive, even when intensive chelating therapy is given and the appearance of Hypogonadism in both sexes is often unavoidable. Close follow up and proper management is crucial for every patient with TM. Early recognition of growth disturbance and prevention of hypogonadism by early and judicious chelation therapy is mandatory for the improvement of their quality of life. Patients with TM can now live a better life due to modern advances in their medical care and our better understanding in the pathogenesis, manifestation and prevention of endocrine complications.

Prevalence of impaired glucose metabolism in beta-thalassemic children receiving hypertransfusions with a suboptimal dosage of iron-chelating therapy

A cross-sectional study of impaired glucose metabolism was carried out in 48 beta-thalassemic patients receiving hypertransfusions. An oral glucose tolerance test (OGTT) was performed using the method and criteria of the American Diabetes Association (ADA). Diabetes mellitus was diagnosed in two patients, and impaired glucose tolerance was found in four patients, giving a prevalence of impaired glucose metabolism of 12.5% in our patient population. The significant clinical characteristics associated with the diagnosis of impaired glucose metabolism were wasting (-2.15/-0.86 SDS, p = 0.025), stunting (-2.69/-1.22 SDS, p = 0.03), higher ferritin levels (8679/4710 microg/L, p = 0.005), splenectomy (50/9.5%, p = 0.012), and lower area under curve (AUC) of insulin secretion after OGTT (40.0/77.7, p = 0.002). The significant decrease of AUC insulin in thalassemic patients with an impaired glucose tolerance test suggests that the pathogenesis may originate from pancreatic beta-cell damage rather than from insulin resistance. In conclusion, the prevalence of impaired glucose tolerance in our population of thalassemic patients receiving hypertransfusions with suboptimal iron chelating therapy was 12.5%. The clinical characteristics of thalassemic patients who developed impaired glucose tolerance were wasting, stunting, higher ferritin levels, splenectomy, and lower AUC insulin.

Bone demineralization in adult thalassaemic patients: contribution of GH and IGF-I at different skeletal sites

BACKGROUND AND OBJECTIVE

GH and IGF-I exert an important role in the control of bone formation, as shown by decreased bone mineral density and increased fracture risk in adult hypopituitary patients untreated for GH deficiency (GHD). Different degrees of bone demineralization are frequently reported in patients affected by beta-thalassaemia. Considering the high prevalence of GHD recently observed by our group among adult thalassaemic patients, we elected to study the possible role of GH-IGF-I abnormalities in the pathogenesis of the osteopenia/osteoporosis of this disease.

DESIGN

Sixty-four adult thalassaemic patients (49 with thalassaemia major and 15 with thalassaemia intermedia, 23 men and 41 women, aged 31.4 +/- 6.8 years) were studied.

METHODS

Bone mineral density was assessed by dual energy X-ray absorptiometry at lumbar spine in 62 patients and at proximal femur in 58. All patients underwent GHRH (1 microg/kg as an i.v. bolus) plus arginine (0.5 g/kg as a 30-min i.v. infusion) testing. Severe GHD was defined by GH peaks < 9 microg/l, whereas partial GHD was defined by GH peaks ranging from 9 to 16.5 microg/l. Blood samples for IGF-I measurement were collected.

RESULTS

Lumbar osteoporosis and osteopenia were demonstrated in 46/62 (74.1%) and 14/62 (22.5%) patients, respectively. Femoral osteoporosis and osteopenia were documented in 22/58 (37.9%) and 32/58 (55.1%) patients, respectively. Severe GHD was demonstrated in 16/64 patients (25%), while 11 additional patients (17.1%) displayed partial GHD. IGF-I standard deviation score (SDS) was low, that is, below -1.88, in the majority (54.6%) of patients. Lumbar T-score values were not correlated with either GH peaks or IGF-I SDS values. Femoral T-score values were positively correlated with GH peaks (r = 0.38, P < 0.005) and IGF-I SDS values (r = 0.39, P < 0.005). Multiple regression analysis pointed to both GH peak and IGF-I SDS as predictors of femoral T-score. Furthermore, mean femoral T-score was significantly lower in patients with severe GHD than in those with normal GH secretion (-2.94 +/- 0.25 vs.-2.15 +/- 0.12, P < 0.01).

CONCLUSION

This study, while confirming the high prevalence of both osteopenia/osteoporosis and somatotropin-somatomedin deficiency in adult thalassaemic patients, indicates that defective GH secretion and diminished serum IGF-I levels may contribute to femoral demineralization in these patients. Further studies are worth carrying out to evaluate the efficacy of biosynthetic GH administration on bone abnormalities of GH-deficient thalassaemic adults.

Endocrinopathies in patients with transfusion-dependent beta-thalassemia

Thalassemia is common in Iran. Appropriate therapy for this disease includes a regular blood transfusion and chelation therapy. However, in this approach patients will inevitably experience side effects, particularly iron overloads in critical organs, including heart, ductless glands, and liver. This study attempted to determine prevalence of adenoidal abnormality between Iranian thalassemia patients for prediagnosis and to offer necessary medical measures. This is a descriptive nonrandomized study and included all the patients suffering from thalassemia major referring to medical centers linked with the Iranian blood transfusion organization from January 2004 to January 2005. All patients were sampled for CBC, FBS, 2-h BS, HbAlC, liver function, renal function, and endocrine disease. Initially, reports of adenoidal experiments as well as other associated parameters were provided from medical records. A total of 437 patients enrolled in the study: 5.4% suffered from diabetes, 1% had hypothyroid, and 1 person showed hypoparathyroidism. The mean levels of ferritin in diabetic and nondiabetic groups and hypothyroid and nonhypothyroid groups were not significantly different. The mean levels of ferritin among various age groups also were not significantly different. Results of a comparison between present research and similar studies conducted throughout Iran and those performed abroad on adenoidal abnormalities in thalassemia patients show that subject patients of this study statistically suffered from fewer difficulties than diabetes patients in other studies.

Liver, bone marrow, pancreas and pituitary gland iron overload in young and adult thalassemic patients: a T2 relaxometry study

Thirty-seven patients with beta-thalassemia major, including 14 adolescents (15.2 +/- 3.0 years) and 23 adults (26.4 +/- 6.9 years), were studied. T2 relaxation time (T2) of the liver, bone marrow, pancreas and pituitary gland was measured in a 1.5-Tesla magnetic resonance (MR) imager, using a multiecho spin-echo sequence (TR/TE 2,000/20, 40, 60, 80, 100, 120, 140, 160 ms). Pituitary gland height was evaluated in a midline sagittal scan of a spin-echo sequence (TR/TE, 500/20 ms). The T2 of the pituitary gland was higher in adolescents (59.4 +/- 15 ms) than in adults (45.3 +/- 10.4 ms), P < 0.05. The T2 of the pancreas was lower in adolescents (43.6 +/- 10.3 ms) than in adults (54.4 +/- 10.4 ms). No difference among groups was found in the T2 of the liver and bone marrow. There was no significant correlation of the T2 among the liver, pancreas, pituitary gland and bone marrow. There was no significant correlation between serum ferritin and T2 of the liver, pancreas and bone marrow. Pituitary T2 showed a significant correlation with pituitary gland height (adolescents: R = 0.63, adults: R = 0.62, P < 0.05) and serum ferritin (adolescents: R = -0.60, adults: R = -0.50, P < 0.05). In conclusion, iron overload evaluated by T2 is organ specific. After adolescence, age-related T2 changes are predominantly associated with pituitary siderosis and fatty degeneration of the pancreas. Pituitary size decreases with progressing siderosis.

Nocturnal calcium, phosphorus and parathyroid hormone in the diagnosis of concealed and subclinical hypoparathyroidism

CONTEXT

Circadian rhythms of plasma parathyroid hormone (PTH) show peak values at night, whereas serum calcium levels peak in the evening and display a nadir at night.

HYPOTHESES

Subclinical hypoparathyroidism (HPT) can be detected by utilizing the knowledge of diurnal variations. Thalassemia major (TM) may provide a model system of subclinical HPT.

DESIGN

Nocturnal plasma PTH and serum calcium values were determined in 13 TM patients with normal morning serum calcium levels as compared with the corresponding values in eight healthy control subjects.

RESULTS

Six patients with TM presented a nadir serum calcium level of 8.3 mg/dl or lower (hypoCa TM) at 0200 h, whereas the remaining seven showed nadir levels of 8.4 mg/dl or higher (normoCa TM). Patients with hypoCa TM displayed a drop between peak and nadir of 1.2 +/- 0.5 mg/dl as compared with a considerably smaller fall of 0.3 +/- 0.7 mg/dl in control subjects (P < 0.05). NormoCa TM patients experienced comparable nocturnal variation to that of control subjects. Patients from both the hypoCa and normoCa TM groups presented significantly lower nocturnal PTH levels than those of control subjects and lost the nocturnal PTH variation characteristic of healthy subjects. A plot of all serum calcium against plasma PTH levels provides a clear distinction of the three groups.

CONCLUSIONS

All 13 daytime normocalcemic TM patients presented a certain degree of HPT. The hypoCa TM group displayed a concealed HPT detected in all, except the morning sampling, whereas normoCa TM patients experienced sub clinical HPT observed in the absence of nocturnal HPT variation. Nocturnal measurements of serum minerals thus enhance the sensitivity of HPT diagnosis.

Low bone mass in children and adolescents

Osteoporosis is a disease characterized by low bone mass and micro architectural alterations of bone tissue leading to enhanced bone fragility and increased fracture risk. Although research in osteoporosis has focused mainly on the role of bone loss in the elderly population, it is becoming increasingly clear that the amount of bone that is gained during growth is also an important determinant of future resistance to fractures. Thus, considerable interest is being placed on defining preventive strategies that optimize the gain of bone mass during childhood and adolescence. Knowledge of the determinants accounting for the physiologic and genetic variations in bone accumulation in children will provide the best means toward the early diagnosis and treatment of osteoporosis. This article reviews the techniques available for bone mass measurements in children and the major determinants and diseases influencing bone accretion during childhood and adolescence.

The impact of genotype on endocrine complications in thalassaemia major

BACKGROUND

The clinical severity in thalassaemia major (TM) depends on the underlying mutations of the beta-globin gene and the degree of iron overload.

OBJECTIVE

The aim of the study was to investigate the impact of genotype on the development of endocrine complications in TM in our center.

SUBJECTS AND METHODS

126 (62 males, 64 females) thalassaemic patients of Greek Cypriot origin with a mean age of 31.2 (17-68) yr were included in the study. All patients, who were on the standard treatment protocol, were subsequently divided into two groups according to their genotype, group A (92): TM with no mitigating factor and group B (34): TM carrying one or more mitigating factors in the beta- and/or alpha-globin genes. Iron overload calculation was based on the amount of red cell consumption and the mean ferritin level over a 12-year period. Statistical analysis was performed with the SPSS program.

RESULTS

Patients in group A, who were consuming larger amounts of blood on transfusions, were more likely to develop hypogonadism (P = 0.001) compared with patients in group B, despite their similar mean ferritin levels. The incidence of other endocrinopathies (short stature, hypothyroidism, and diabetes mellitus) was similar in the two groups. The prevalence of hypothyroidism in splenectomized patients was significantly higher (P = 0.005), whereas the presence of hypogonadism, impaired glucose homeostasis and insulin resistance, although more frequent, was not statistically significant. The clinical severity of TM had no impact on bone mineral density (BMD) in both men and women. BMD was only influenced by gonadal function.

CONCLUSIONS

This study demonstrates that the underlying genetic defect in TM is a contributing factor for gonadal dysfunction, because the patients with the more severe defects have a greater rate of iron loading through higher red cell consumption.

Osteoporosis and measurement of bone mass in children and adolescents

Osteoporosis increasingly is recognized as a pediatric concern. Fragility fractures occur in children and adolescents with genetic disorders and those with a variety of chronic diseases. Others may not fracture in childhood but reach adulthood with a reduced peak bone mass and increased lifelong risk of osteoporosis. This article reviews the indications for pediatric bone density testing, the strengths and limitations of densitometry methods, and the challenges of interpreting the results. The goals are to demystify the densitometry report and to clarify the role of bone density tests in assessing and managing skeletal health in children.

Hypogonadotropic hypogonadism and hematologic phenotype in patients with transfusion-dependent beta-thalassemia

OBJECTIVE

To determine the prevalence and risk factors of hypogonadotropic hypogonadism in transfusion-dependent patients with thalassemia.

PATIENTS AND METHODS

The authors examined 29 patients with thalassemia major aged 15 years or older. Luteinizing hormone-releasing hormone tests were performed and beta-thalassemia mutations were analyzed by direct sequencing.

RESULTS

The prevalence of hypogonadotropic hypogonadism was 72%. Failure of puberty was observed in 5 of 11 (45%) boys and 7 of 18 (39%) girls. Arrested puberty was noted in two boys (18%) and five girls (28%). Ten girls (56%) did not menstruate, two (11%) had regular menstrual cycles, one (6%) had irregular menstrual cycles, and five (28%) developed secondary amenorrhea. Twenty-one and eight patients had the beta 0/beta 0 and beta 0/beta+ hematologic phenotypes, respectively. beta 0-thalassemia mutation alleles involved IVS II-654 (C-T), codons 41/42 (-TCTT), codons 27/28 (+C), and codons 17 (A-T). beta+-thalassemia mutations alleles were -28 (A-G) and HbE (codons 26(GAG-AAG)). Hematologic phenotype (odds ratio, 28.50; P = 0.002) was the only risk factor identified in the logistic regression analysis.

CONCLUSIONS

In patients with thalassemia major, genetic differences may influence their susceptibility to hypogonadotropic hypogonadism, possibly as a result of differences in the amounts of blood transfused and/or their vulnerability to free radical damage. The hematologic phenotype is a main determinant of the severity of thalassemia major; hence, it may influence the need for and frequency of blood transfusion and the patient's iron-overload status.

Growth hormone secretion in polytransfused prepubertal patients with homozygous beta-thalassemia. Effect of long-term recombinant GH (recGH) therapy

Growth was monitored in 133 male and 150 female North Sardinian prepubertal patients with homozygous beta-thalassemia in order to ascertain the incidence of GH deficiency (GHD) and the effects of long-term recombinant GH (recGH) treatment on growth velocity and bone maturation. A significant reduction in growth velocity and a fall in IGF-I levels was observed in 19 male and 16 female patients (12.3%). Their peak GH responses to GHRH (5.45+/-0.78 and 4.99+/-0.86 ng/ml) and clonidine administration (4.21+/-0.32 and 4.15+/-0.27 ng/ml in males and females, respectively) were markedly reduced with respect to control subjects (p<0.01). No statistically significant correlation was found between chronological age, number of blood units received, plasma ferritin levels and plasma IGF-I levels as well as with peak GH response to stimulation. Thalassemic patients with GHD had plasma ferritin levels (1382.44+/-160.34 and 1255.23+/-139.81 ng/ml in males and females, respectively) significantly lower than those recorded in the other patients (2848.94+/-283.61 and 3077.82+/-220.51 ng/ml). Patients with GHD were treated with recGH for an average period of 59 months (range 26-124). Treatment was able to restore growth and to increase significantly plasma IGF-I levels. Growth velocity at the end of the first yr of treatment was 6.78+/-1.21 and 6.11+/-0.85 cm/yr in males and females, respectively. Growth velocity values and plasma IGF-I levels remained significantly higher than basal values throughout the period of treatment. However, treatment was unable to normalize bone maturation since bone age values were always reduced with respect to chronological age. No incidence of side effects was observed. These data indicate that GHD, when present, is one but not the sole cause of delayed bone maturation and height deficiency in thalassemia.