Evaluation of growth and hormonal status in patients referred to the International Fanconi Anemia Registry

Longitudinal clinical manifestations of Fanconi anemia: A systematized review

Fanconi anemia (FA) is a rare and complex inherited genetic disorder characterized by impaired DNA repair mechanisms leading to genomic instability. Individuals with FA have increased susceptibility to congenital anomalies, progressive bone marrow failure, leukemia and malignant tumors, endocrinopathies and other medical issues. In recent decades, steadily improved approaches to hematopoietic cell transplantation (HCT), the only proven curative therapy for the hematologic manifestations of FA, have significantly increased the life expectancy of affected individuals, illuminating the need to understand the long-term consequences and multi-organ ramifications. Utilizing a systematized review approach with narrative synthesis of each primary issue and organ system, we shed light on the challenges and opportunities for optimizing the care and quality of life for individuals with FA and identify knowledge gaps informing future research directions.

A Narrative Review on Fanconi Anemia: Genetic and Diagnostic Considerations

Fanconi anemia (FA) is an autosomal recessive disorder, both genetically and phenotypically. It is characterized by chromosomal instability, progressive bone marrow failure, susceptibility to cancer, and various other congenital abnormalities. It involves all the three cell lines of blood. So far, biallelic mutations in 21 genes and one x-linked gene have been detected and found to be associated with FA phenotype. Signs and symptoms start setting in by the age of 4 to 7 years, mainly hematological symptoms. This includes pancytopenia, that is, a reduction in the number of white blood cells (WBCs), red blood cells (RBCs), and platelets. Therefore, the main criteria for diagnosis of FA include skeletal malformations, pancytopenia, hyperpigmentation, short stature, urogenital abnormalities, central nervous system, auditory, renal, ocular, and familial occurrence. Patients showing signs and symptoms of FA should be thoroughly evaluated. A complete blood count will reveal a reduced number of RBC, WBC, and platelets, that is, pancytopenia. Chromosomal breakage study/stress cytogenetics should be done in patients with severe pancytopenia. Momentousness timely diagnosis of current disease, prenatal diagnosis, and genetic counseling should be emphasized.

Tryptophan metabolism is dysregulated in individuals with Fanconi anemia

Fanconi anemia (FA) is a complex genetic disorder associated with progressive marrow failure and a strong predisposition to malignancy. FA is associated with metabolic disturbances such as short stature, insulin resistance, thyroid dysfunction, abnormal body mass index (BMI), and dyslipidemia. We studied tryptophan metabolism in FA by examining tryptophan and its metabolites before and during the stress of hematopoietic stem cell transplant (HSCT). Tryptophan is an essential amino acid that can be converted to serotonin and kynurenine. We report here that serotonin levels are markedly elevated 14 days after HSCT in individuals with FA, in contrast to individuals without FA. Kynurenine levels are significantly reduced in individuals with FA compared with individuals without FA, before and after HSCT. Most peripheral serotonin is made in the bowel. However, serotonin levels in stool decreased in individuals with FA after transplant, similar to individuals without FA. Instead, we detected serotonin production in the skin in individuals with FA, whereas none was seen in individuals without FA. As expected, serotonin and transforming growth factor β (TGF-β) levels were closely correlated with platelet count before and after HSCT in persons without FA. In FA, neither baseline serotonin nor TGF-B correlated with baseline platelet count (host-derived platelets), only TGF-B correlated 14 days after transplant (blood bank-derived platelets). BMI was negatively correlated with serotonin in individuals with FA, suggesting that hyperserotonemia may contribute to growth failure in FA. Serotonin is a potential therapeutic target, and currently available drugs might be beneficial in restoring metabolic balance in individuals with FA.

Endocrine profiling in patients with Fanconi anemia, homozygous for a FANCG founder mutation

BACKGROUND

Fanconi anemia (FA) is phenotypically diverse, hereditary condition associated with bone marrow failure, multiple physical abnormalities, and an increased susceptibility to the development of malignancies. Less recognized manifestations of FA include endocrine abnormalities. International discourse has highlighted that these abnormalities are widespread among children and adults with FA. To date there has been no systematic study that has evaluated the endocrine abnormalities in a cohort of patients with FA, homozygous for a founder mutation (c.637_643del (p.Tyr213Lysfs*6)) in FANCG. The objectives of the study were to evaluate endocrine gland function in patients with FA of a single FA genotype, and to determine the frequency and nature of endocrine abnormalities in this group.

METHODS

Cross-sectional, descriptive study of 24 South African patients of African ancestry with FA (homozygous for a FANCG founder mutation). Outcomes measured included growth, pubertal status, growth hormone axis screening, thyroid gland function, glucose and insulin metabolism and bone age (BA).

RESULTS

Endocrine dysfunction was present in 70.8% (17 of 24), including abnormal insulin-like growth factor 1 (IGF-1)/insulin-like growth factor-binding protein 3 (IGFBP-3) in 25.0% (6 of 24), insulin resistance in 41.7% (10 of 24), abnormal thyroid function in 16.7% (4 of 24) and short stature in 45.8% (11 of 24). No abnormalities of glucose metabolism were identified. Abnormal pubertal status was seen in three males (12.5%). Abnormal BAs were present in 34.8% (8 of 23).

CONCLUSION

Endocrine abnormalities occur at a high frequency in patients with FA, homozygous for a FANCG founder mutation, similar to other FA cohorts. Our data are specific to FA patients with a single genotype, and therefore provide the first genotype-phenotype information on endocrine abnormalities in South African patients, homozygous for a FANCG founder mutation. Recommendations regarding endocrine screening in this patient subgroup are made, including, but not limited to, baseline testing of thyroid function, fasted insulin and glucose, and IGF-1 and IGFBP-3.

Peptide Hormone Regulation of DNA Damage Responses

DNA damage response (DDR) and DNA repair pathways determine neoplastic cell transformation and therapeutic responses, as well as the aging process. Altered DDR functioning results in accumulation of unrepaired DNA damage, increased frequency of tumorigenic mutations, and premature aging. Recent evidence suggests that polypeptide hormones play a role in modulating DDR and DNA damage repair, while DNA damage accumulation may also affect hormonal status. We review the available reports elucidating involvement of insulin-like growth factor 1 (IGF1), growth hormone (GH), α-melanocyte stimulating hormone (αMSH), and gonadotropin-releasing hormone (GnRH)/gonadotropins in DDR and DNA repair as well as the current understanding of pathways enabling these actions. We discuss effects of DNA damage pathway mutations, including Fanconi anemia, on endocrine function and consider mechanisms underlying these phenotypes. (Endocrine Reviews 41: 1 - 19, 2020).

Mitoprotective Clinical Strategies in Type 2 Diabetes and Fanconi Anemia Patients: Suggestions for Clinical Management of Mitochondrial Dysfunction

Oxidative stress (OS) and mitochondrial dysfunction (MDF) occur in a number of disorders, and several clinical studies have attempted to counteract OS and MDF by providing adjuvant treatments against disease progression. The present review is aimed at focusing on two apparently distant diseases, namely type 2 diabetes (T2D) and a rare genetic disease, Fanconi anemia (FA). The pathogenetic links between T2D and FA include the high T2D prevalence among FA patients and the recognized evidence for OS and MDF in both disorders. This latter phenotypic/pathogenetic feature-namely MDF-may be regarded as a mechanistic ground both accounting for the clinical outcomes in both diseases, and as a premise to clinical studies aimed at counteracting MDF. In the case for T2D, the working hypothesis is raised of evaluating any in vivo decrease of mitochondrial cofactors, or mitochondrial nutrients (MNs) such as α-lipoic acid, coenzyme Q10, and l-carnitine, with possibly combined MN-based treatments. As for FA, the established knowledge of MDF, as yet only obtained from in vitro or molecular studies, prompts the requirement to ascertain in vivo MDF, and to design clinical studies aimed at utilizing MNs toward mitigating or delaying FA's clinical progression. Altogether, this paper may contribute to building hypotheses for clinical studies in a number of OS/MDF-related diseases.

Growth Disturbances in Childhood Cancer Survivors

Survival from childhood cancer has improved dramatically over the last few decades, resulting in an increased need to address the long-term follow-up and care of childhood cancer survivors. Appropriate linear growth is an important measure of health, with alterations of growth in children and short adult height in those who have completed growth serving as potential indicators of the sequelae of the underlying diagnosis or the cancer treatments. It is therefore critical that clinicians, particularly endocrinologists, be familiar with the patterns of altered growth which may be seen following diagnosis and treatment for childhood cancer. In this article, we will review the growth alterations seen in childhood cancer survivors, focusing on risk factors and considerations in evaluation and care.

Delineating the role of FANCA in glucose-stimulated insulin secretion in β cells through its protein interactome

Hyperinsulinemia affects 72% of Fanconi anemia (FA) patients and an additional 25% experience lowered glucose tolerance or frank diabetes. The underlying molecular mechanisms contributing to the dysfunction of FA pancreas β cells is unknown. Therefore, we sought to evaluate the functional role of FANCA, the most commonly mutated gene in FA, in glucose-stimulated insulin secretion (GSIS). This study reveals that FANCA or FANCB knockdown impairs GSIS in human pancreas β cell line EndoC-βH3. To identify potential pathways by which FANCA might regulate GSIS, we employed a proteomics approach to identify FANCA protein interactions in EndoC-βH3 differentially regulated in response to elevated glucose levels. Glucose-dependent changes in the FANCA interaction network were observed, including increased association with other FA family proteins, suggesting an activation of the DNA damage response in response to elevated glucose levels. Reactive oxygen species increase in response to glucose stimulation and are necessary for GSIS in EndoC-βH3 cells. Glucose-induced activation of the DNA damage response was also observed as an increase in the DNA damage foci marker γ-H2AX and dependent upon the presence of reactive oxygen species. These results illuminate the role of FANCA in GSIS and its protein interactions regulated by glucose stimulation that may explain the prevalence of β cell-specific endocrinopathies in FA patients.

Sex-specific hepatic lipid and bile acid metabolism alterations in Fancd2-deficient mice following dietary challenge

Defects in the Fanconi anemia (FA) DNA damage-response pathway result in genomic instability, developmental defects, hematopoietic failure, cancer predisposition, and metabolic disorders. The endogenous sources of damage contributing to FA phenotypes and the links between FA and metabolic disease remain poorly understood. Here, using mice lacking the Fancd2 gene, encoding a central FA pathway component, we investigated whether the FA pathway protects against metabolic challenges. Fancd2 ^-/- and wildtype (WT) mice were fed a standard diet (SD), a diet enriched in fat, cholesterol, and cholic acid (Paigen diet), or a diet enriched in lipid alone (high-fat diet (HFD)). Fancd2 ^-/- mice developed hepatobiliary disease and exhibited decreased survival when fed a Paigen diet but not a HFD. Male Paigen diet-fed mice lacking Fancd2 had significant biliary hyperplasia, increased serum bile acid concentration, and increased hepatic pathology. In contrast, female mice were similarly impacted by Paigen diet feeding regardless of Fancd2 status. Upon Paigen diet challenge, male Fancd2 ^-/- mice had altered expression of genes encoding hepatic bile acid transporters and cholesterol and fatty acid metabolism proteins, including Scp2/x, Abcg5/8, Abca1, Ldlr, Srebf1, and Scd-1 Untargeted lipidomic profiling in liver tissue revealed 132 lipid species, including sphingolipids, glycerophospholipids, and glycerolipids, that differed significantly in abundance depending on Fancd2 status in male mice. We conclude that the FA pathway has sex-specific impacts on hepatic lipid and bile acid metabolism, findings that expand the known functions of the FA pathway and may provide mechanistic insight into the metabolic disease predisposition in individuals with FA.

Deletion of the Fanconi Anemia C Gene in Mice Leads to Skeletal Anomalies and Defective Bone Mineralization and Microarchitecture

Fanconi anemia (FA) is a rare genetic disorder associated with a progressive decline in hematopoietic stem cells leading to bone marrow failure. FA is also characterized by a variety of developmental defects including short stature and skeletal malformations. More than half of children affected with FA have radial-ray abnormalities, and many patients have early onset osteopenia/osteoporosis. Although many Fanconi anemia genes have been identified and a molecular pathway defined, the underlying mechanism leading to bone defects remains elusive. To understand the role of FA genes in skeletal development and bone microarchitecture, we evaluated bone physiology during embryogenesis and in adult FancA- and FancC-deficient mice. We found that both FancA^-/- and FancC^-/- embryos have abnormal skeletal development shown by skeletal malformations, growth delay, and reduced bone mineralization. FancC^-/- adult mice present altered bone morphology and microarchitecture with a significant decrease in cortical bone mineral density in a sex-specific manner. Mechanical testing revealed that male but not female FancC^-/- mice show reduced bone strength compared with their wild-type littermates. Ex vivo cultures showed that FancA^-/- and FancC^-/- bone marrow-derived mesenchymal stem cells (_BM MSC) have impaired differentiation capabilities together with altered gene expression profiles. Our results suggest that defective bone physiology in FA occurs in utero and possibly results from altered _BM MSC function. These results provide valuable insights into the mechanism involved in FA skeletal defects. © 2018 American Society for Bone and Mineral Research.

A Homozygous Missense Mutation in FANCA Gene in a 46,XY Female with Gonadal Dysgenesis

Fanconi anemia (FA) is a pleiotropic condition with 2 characteristic phenotypic markers of hematological and cytogenetic changes. The phenotype of patients with FA is very heterogeneous, associated with an array of congenital malformations affecting the skeletal, renal, genital, and/or central nervous systems. Here, we report on a 46,XY female who presented with gonadal dysgenesis and microcephaly. Exome sequencing showed that she was homozygous for a rare variant in the FANCA gene (c.4232C>T, p.P1411L, rs201494304). Both parents were heterozygous for the mutation. The FA mutation was associated with an atypical clinical presentation, and thus exome sequencing provided essential data that otherwise would have been overlooked in the diagnosis of this patient.

A study of facial pattern in patients with fanconi anemia

OBJECTIVE

This study is aimed to evaluate craniofacial features in patients with Fanconi anemia (FA) through cephalometric analysis and to classify the facial growth pattern to observe possible facial discrepancies.

DESIGN

This is a cross-sectional study which employed a quantitative approach to compare linear and angular measurements of cephalometric analysis in lateral teleradiographic images of a clinical type sample of patients with FA. A retrospective cephalometric study was performed using cephalometric analyses of Ricketts and Steiner; growth patterns according to Ricketts' vertical growth pattern (VERT index) were also analyzed.

PATIENTS

Fifty patients diagnosed with FA who were undergoing anti-aplasia treatment at the outpatient Hematology service at the Federal University of Paraná, Curitiba, Brazil were included in the study.

INTERVENTIONS

The patients were evaluated in the School of Dentistry of the Pontifical Catholic University of Paraná (PUCPR), Curitiba, Brazil. Exclusion criteria included patients who had used or were using growth hormone medication, had undergone bone marrow transplant, or had been previously subjected to dental treatment.

MAIN OUTCOME MEASURES

Cephalometric points were plotted in order to set up linear and angular cephalometric measurements. Angular and linear measurements from 17 factors proposed by Ricketts' cephalometric analysis were assessed.

RESULTS

Dolicofacial appearance was observed in 52% of individuals; braquifacial in 28%, and mesofacial in 20%. Significant maxillary/mandibular discrepancy was observed. It was concluded that upon anteroposterior evaluation of facial bone structures, the FA sample presented smaller median measurements in most variables evaluated; it also presented mandibular micrognathism and mainly dolicofacial vertical growth pattern. These findings, together with other features such as skin pigmentation and microphthalmia, may lead to a possible recognition of a FA condition from a patient's facial features.

DNA Damage as a Driver for Growth Delay: Chromosome Instability Syndromes with Intrauterine Growth Retardation

DNA is constantly exposed to endogenous and exogenous mutagenic stimuli that are capable of producing diverse lesions. In order to protect the integrity of the genetic material, a wide array of DNA repair systems that can target each specific lesion has evolved. Despite the availability of several repair pathways, a common general program known as the DNA damage response (DDR) is stimulated to promote lesion detection, signaling, and repair in order to maintain genetic integrity. The genes that participate in these pathways are subject to mutation; a loss in their function would result in impaired DNA repair and genomic instability. When the DDR is constitutionally altered, every cell of the organism, starting from development, will show DNA damage and subsequent genomic instability. The cellular response to this is either uncontrolled proliferation and cell cycle deregulation that ensues overgrowth, or apoptosis and senescence that result in tissue hypoplasia. These diverging growth abnormalities can clinically translate as cancer or growth retardation; both features can be found in chromosome instability syndromes (CIS). The analysis of the clinical, cellular, and molecular phenotypes of CIS with intrauterine growth retardation allows inferring that replication alteration is their unifying feature.

Growth hormone treatment in patients with ataxia telangiectasia

INTRODUCTION

Ataxia telangiectasia (A-T) is a devastating autosomal recessive disorder with chromosomal instability and growth failure. Low levels of growth hormone (GH) and growth factors may be related to advanced neurological deterioration, wasting syndrome and more pronounced immunodeficiency.

OBJECTIVE

The objective of this study is to study safety and effectiveness of GH therapy in patients with A-T and evaluate the effect of GH on ataxia and lymphocyte subsets.

METHODS

Three patients with classical A-T were treated with GH (0.3 mg/kg/d) for 1 year. Growth rate, ataxia score and lymphocyte subsets were monitored.

RESULTS

GH treatment was well tolerated. All patients showed a significant increase of height SDS of +1.3 (mean height SDS -1.994), a mean increase of 8 (6-11) cm/12 months. Lymphocytes subsets and ataxia were not altered before and after GH treatment.

CONCLUSIONS

Treatment with GH is feasible and effective in A-T patients with severe growth arrest, but no effect on ataxia and lymphocytes could be recorded.

An abnormal bone marrow microenvironment contributes to hematopoietic dysfunction in Fanconi anemia

Fanconi anemia is a complex heterogeneous genetic disorder with a high incidence of bone marrow failure, clonal evolution to acute myeloid leukemia and mesenchymal-derived congenital anomalies. Increasing evidence in Fanconi anemia and other genetic disorders points towards an interdependence of skeletal and hematopoietic development, yet the impact of the marrow microenvironment in the pathogenesis of the bone marrow failure in Fanconi anemia remains unclear. Here we demonstrated that mice with double knockout of both Fancc and Fancg genes had decreased bone formation at least partially due to impaired osteoblast differentiation from mesenchymal stem/progenitor cells. Mesenchymal stem/progenitor cells from the double knockout mice showed impaired hematopoietic supportive activity. Mesenchymal stem/progenitor cells of patients with Fanconi anemia exhibited similar cellular deficits, including increased senescence, reduced proliferation, impaired osteoblast differentiation and defective hematopoietic stem/progenitor cell supportive activity. Collectively, these studies provide unique insights into the physiological significance of mesenchymal stem/progenitor cells in supporting the marrow microenvironment, which is potentially of broad relevance in hematopoietic stem cell transplantation.

Fanconi anemia protein FANCD2 is activated by AICAR, a modulator of AMPK and cellular energy metabolism

FANCD2 is a pivotal molecule in the pathogenesis of Fanconi anemia (FA), an autosomal recessive human syndrome with diverse clinical phenotypes, including cancer predisposition, short stature, and hematological abnormalities. In our previous study, we detected the functional association of FANC proteins, whose mutations are responsible for the onset of FA, with AMPK in response to DNA interstrand crosslinking lesions. Because AMPK is well known as a critical sensing molecule for cellular energy levels, we checked whether FANCD2 activation occurs after treatments affecting AMPK and/or cellular energy status. Among the treatments tested, AMPK‐activating 5‐aminoimidazole‐4‐carboxamide‐ribonucleoside (AICAR) induced monoubiquitination and nuclear foci formation of FANCD2, which are biomarkers of FANCD2 activation. FANCD2 activation was abolished by treatments with Compound C, an AMPK inhibitor, or after AMPKα1 knockdown, substantiating the involvement of AMPK in AICAR‐induced FANCD2 activation. Similarly, FANCA protein, which is a component of the FA core complex monoubiquitinating FANCD2, was required for this event. Furthermore, FANCD2 repression enhanced cell death upon AICAR treatments in transformed fibroblasts and cell cycle arrest in the renal cell carcinoma cell line Caki‐1. Overall, this study showed FANCD2 involvement in response to AICAR, a chemical modulating cellular energy metabolism.

Fanconi Anemia and Laron Syndrome

BACKGROUND

Fanconi anemia (FA) is a condition characterized by genetic instability and short stature, which is due to growth hormone (GH) deficiency in most cases. However, no apparent relationships have been identified between FA complementation group genes and GH. In this study, we thereby considered an association between FA and Laron syndrome (LS) (insulin-like growth factor 1 [IGF-1] deficiency).

METHODS

A 21-year-old female Mexican patient with a genetic diagnosis of FA was referred to our research department for an evaluation of her short stature. Upon admission to our facility, her phenotype led to a suspicion of LS; accordingly, serum levels of IGF-1 and IGF binding protein 3 were analyzed and a GH stimulation test was performed. In addition, we used a next-generation sequencing approach for a molecular evaluation of FA disease-causing mutations and genes involved in the GH-IGF signaling pathway.

RESULTS

Tests revealed low levels of IGF-1 and IGF binding protein 3 that remained within normal ranges, as well as a lack of response to GH stimulation. Sequencing confirmed a defect in the GH receptor signaling pathway.

CONCLUSIONS

To the best of our knowledge, this study is the first to suggest an association between FA and LS. We propose that IGF-1 administration might improve some FA complications and functions based upon IGF-1 beneficial actions observed in animal, cell and indirect clinical models: erythropoiesis modulation, immune function improvement and metabolic regulation.

Endocrinopathies, Bone Health, and Insulin Resistance in Patients with Fanconi Anemia after Hematopoietic Cell Transplantation

A number of endocrinopathies have been described after hematopoietic cell transplantation (HCT), but data are limited in patients with Fanconi anemia (FA). We report several endocrine-based disorders in a cohort of 44 patients with FA after HCT compared with both 74 patients who received HCT for hematologic malignancies and with 275 healthy controls. Endocrinopathies assessed included hypothyroidism, hypogonadism, short stature, dyslipidemia, insulin resistance, abnormalities in body composition, and bone health. Most (86%) patients with FA had at least 1 endocrinopathy, with 11% having 3 or more. Hypothyroidism was seen in 57%, hypogonadism in 27%, short stature in 50%, and reduced total body and lumbar spine bone mineral density (BMD) (height adjusted Z-score < -1) in 57% and 21%, respectively. Vitamin D deficiency was seen in 71%. Short stature was associated with younger age at HCT and gonadal failure was associated with older age at HCT. Insulin resistance was associated with increased percent fat mass and increased android/gynoid ratio by dual energy X-ray absorptiometry. Hypothyroidism, short stature, and reduced total body BMD were more prevalent in patients with FA compared with patients with hematologic malignancies. We recommend an assessment before transplantation and close follow-up afterwards to ensure proper clinical management. Future studies should continue to explore the impact of HCT on endocrinopathies in FA patients.

Fanconi Anemia: Overview of the Disease and the Role of Hematopoietic Transplantation

Fanconi anemia (FA) is an inherited bone marrow failure syndrome characterized by congenital abnormalities and chromosomal breakages with the occurrence of hematological and solid malignancies. FA is the most common type of inherited bone marrow failure and poses tremendous challenges. FA patients are uniquely hypersensitive to hematopoietic stem cell transplantation (HSCT) conditioning agents due to the underling chromosomal instability. HSCT has shown important progress in the last years, especially after the introduction of fludarabine and the reduction of cyclophosphamide in the preparative regimen. For patients with HLA-identical-related donors HSCT should be performed as first-line therapy, for patients with alternative donors HSCT remains a therapy with increased morbidity and mortality.

Risk of Neoplasia in Pediatric Patients Receiving Growth Hormone Therapy--A Report From the Pediatric Endocrine Society Drug and Therapeutics Committee

CONTEXT

GH and IGF-1 have been shown to affect tumor growth in vitro and in some animal models. This report summarizes the available evidence on whether GH therapy in childhood is associated with an increased risk of neoplasia during treatment or after treatment is completed.

EVIDENCE ACQUISITION

A PubMed search conducted through February 2014 retrieved original articles written in English addressing GH therapy and neoplasia risk. Subsequent searches were done to include additional relevant publications.

EVIDENCE SYNTHESIS

In children without prior cancer or known risk factors for developing cancer, the clinical evidence does not affirm an association between GH therapy during childhood and neoplasia. GH therapy has not been reported to increase the risk for neoplasia in this population, although most of these data are derived from postmarketing surveillance studies lacking rigorous controls. In patients who are at higher risk for developing cancer, current evidence is insufficient to conclude whether or not GH further increases cancer risk. GH treatment of pediatric cancer survivors does not appear to increase the risk of recurrence but may increase their risk for subsequent primary neoplasms.

CONCLUSIONS

In children without known risk factors for malignancy, GH therapy can be safely administered without concerns about an increased risk for neoplasia. GH use in children with medical diagnoses predisposing them to the development of malignancies should be critically analyzed on an individual basis, and if chosen, appropriate surveillance for malignancies should be undertaken. GH can be used to treat GH-deficient childhood cancer survivors who are in remission with the understanding that GH therapy may increase their risk for second neoplasms.

Endocrine disorders in Fanconi anemia: recommendations for screening and treatment

CONTEXT

Endocrine problems are common in patients with Fanconi anemia (FA). About 80% of children and adults with FA have at least one endocrine abnormality, including short stature, GH deficiency, abnormal glucose or insulin metabolism, dyslipidemia, hypothyroidism, pubertal delay, hypogonadism, or impaired fertility. The goal of this report is to provide an overview of endocrine abnormalities and guidelines for routine screening and treatment to allow early diagnosis and timely intervention.

EVIDENCE ACQUISITION

This work is based on a comprehensive literature review, including relevant articles published between 1971 and 2014, and proceedings of a Consensus Conference held by the Fanconi Anemia Research Fund in 2013.

EVIDENCE SYNTHESIS

The panel of experts collected published evidence and discussed its relevance to reflect current information about the endocrine care of children and adults with FA before the Consensus Conference and through subsequent deliberations that led to the consensus.

CONCLUSIONS

Individuals with FA should be routinely screened for endocrine abnormalities, including evaluation of growth; glucose, insulin, and lipid metabolism; thyroid function; puberty; gonadal function; and bone mineral metabolism. Inclusion of an endocrinologist as part of the multidisciplinary patient care team is key to providing comprehensive care for patients with FA.

Bone mineral density in children with fanconi anemia after hematopoietic cell transplantation

Fanconi anemia (FA) is an inherited DNA repair disorder associated with short stature and bone marrow failure, usually requiring hematopoietic cell transplantation (HCT). Although low bone mineral density (BMD) has been reported in leukemia patients after HCT, little is known about BMD in FA children after HCT (FA HCT). This study's goals were to compare BMD in FA HCT to BMD in healthy controls and in children who received HCT for hematologic malignancy (cancer HCT), and to test for associations between BMD and risk factors for bone loss. This cross-sectional study included 20 FA HCT, 13 cancer HCT, and 90 healthy controls, age-matched and <18 years old at evaluation. BMD Z-scores for total body (TBMD) and lumbar spine (LBMD) were measured by dual energy x-ray absorptiometry and adjusted for height-for-age Z-score (HAZ). FA HCT had lower mean TBMDHAZ Z-score (by .8 SD) and higher fraction with Z-score ≤ -1 than healthy controls (42% versus 11%). No LBMD deficits were detected. FA HCT and cancer HCT groups did not differ significantly in TBMD or LBMD Z-scores. In FA HCT patients, lower body mass index and lower percent fat were associated with lower BMD. This study highlights the importance of monitoring BMD to optimize bone health in FA patients.

Growth retardation and growth hormone deficiency in patients with Ataxia telangiectasia

BACKGROUND

Ataxia telangiectasia (A-T) is a devastating human recessive disorder characterised by progressive cerebellar ataxia, immunodeficiency, genetic instability, and cancer susceptibility. In addition, many patients suffer from growth failure.

METHODS

We analyzed growth and IGF-1/BP3 levels of 24 A-T-patients compared with an age-matched group of healthy controls (n = 36).

RESULTS

Ten (41.7%) A-T patients and none of healthy controls had an IGF-1 level below the 3rd percentile for age. The growth hormone (GH) stimulation tests revealed a severe GH deficiency with no increase of >5 ng/ml in six of the ten A-T patients. The IGF-1 generation tests revealed normal increases in IGF-1 values in all patients.

CONCLUSION

Our results show that a disturbance in the GH/IGF-1 axis was present in 58.3% of A-T patients. Low levels of GH were the result of reduced central GH secretion. GH treatment may be a therapeutic option for A-T patients with severe growth failure.

Fanconi anemia and the cell cycle: new perspectives on aneuploidy

Fanconi anemia (FA) is a complex heterogenic disorder of genomic instability, bone marrow failure, cancer predisposition, and congenital malformations. The FA signaling network orchestrates the DNA damage recognition and repair in interphase as well as proper execution of mitosis. Loss of FA signaling causes chromosome instability by weakening the spindle assembly checkpoint, disrupting centrosome maintenance, disturbing resolution of ultrafine anaphase bridges, and dysregulating cytokinesis. Thus, the FA genes function as guardians of genome stability throughout the cell cycle. This review discusses recent advances in diagnosis and clinical management of Fanconi anemia and presents the new insights into the origins of genomic instability in FA. These new discoveries may facilitate the development of rational therapeutic strategies for FA and for FA-deficient malignancies in the general population.

Genomic analysis of primordial dwarfism reveals novel disease genes

Primordial dwarfism (PD) is a disease in which severely impaired fetal growth persists throughout postnatal development and results in stunted adult size. The condition is highly heterogeneous clinically, but the use of certain phenotypic aspects such as head circumference and facial appearance has proven helpful in defining clinical subgroups. In this study, we present the results of clinical and genomic characterization of 16 new patients in whom a broad definition of PD was used (e.g., 3M syndrome was included). We report a novel PD syndrome with distinct facies in two unrelated patients, each with a different homozygous truncating mutation in CRIPT. Our analysis also reveals, in addition to mutations in known PD disease genes, the first instance of biallelic truncating BRCA2 mutation causing PD with normal bone marrow analysis. In addition, we have identified a novel locus for Seckel syndrome based on a consanguineous multiplex family and identified a homozygous truncating mutation in DNA2 as the likely cause. An additional novel PD disease candidate gene XRCC4 was identified by autozygome/exome analysis, and the knockout mouse phenotype is highly compatible with PD. Thus, we add a number of novel genes to the growing list of PD-linked genes, including one which we show to be linked to a novel PD syndrome with a distinct facial appearance. PD is extremely heterogeneous genetically and clinically, and genomic tools are often required to reach a molecular diagnosis.

Oxandrolone for the treatment of bone marrow failure in Fanconi anemia

BACKGROUND

A majority of Fanconi anemia (FA) patients will experience bone marrow failure (BMF) and androgen therapy (most often oxymetholone) may be utilized as a treatment to improve BMF-related cytopenias. However, oxymetholone is associated with toxicities making identification of other agents of interest. In this study we aimed to evaluate the toxicity profile and hematologic response in patients with FA who are treated with low-dose oxandrolone, a synthetic non-fluorinated anabolic steroid, similar to oxymetholone, with known dosing thresholds for virilization.

PROCEDURE

A single arm, Phase I/II study was designed to treat patients on low-dose oxandrolone. If no toxicity or hematologic response was noted at 16 weeks, a single dose escalation was offered. Subjects were regularly assessed for toxicity, including determinations of virilization, behavioral changes, and liver and kidney function. At 32 weeks, those who demonstrated hematologic response were allowed to continue study treatment, and those without improvement were deemed non-responsive.

RESULTS

Nine subjects completed the study and were followed for a median of 99 weeks (46-136 weeks). Three (33.3%) subjects developed mild sub-clinical virilization and continued treatment with a dose reduction. None (0%) had adverse behavioral changes. Two (22.2%) developed elevated liver function tests at 42 and 105 weeks. Seven (77.8%) subjects had a hematologic response.

CONCLUSION

Oxandrolone appears to be well-tolerated, has limited toxicities at the administered doses in FA with patients, and may be an alternative androgen for the treatment of BMF in FA.

The concept and practice of Fanconi Anemia: from the clinical bedside to the laboratory bench

Fanconi Anemia (FA) is characterised with multiple gene mutations, multiple types of genetic abnormalities, multiple organ involvements and multiple types of cancer risks. It is a life threatening disease commonly at 5 years old children. Research on FA is one of the fastest areas in medical research field. The identification of 15 different FA genes and the elucidation of the FA molecular pathways have translated into the understanding of the pathogenic mechanism and practically provided the directions for therapies. Studies on FA rendered invaluable information for the studies on cancers because FA possesses the unique features in many different biological aspects. Studies revealed the genetic linking between FA and cancers that FA genes are in cancers and cancers genes are in FA. As a result, FA is named as a paradigmatic disease for the understanding of cancer and aging. In clinical practice, an early and accurate diagnosis of FA before the stage of bone marrow failure, cancer/leukemia is crucial for the adequate treatment, the prevention of serious medical complications and also for the properly management in the other caring areas including paediatric, hematology, immunology, endocrinology, reproductive/IVF, obstetrics and surgery. However, an early and accurate diagnosis for FA is often difficult because FA is genetically and phenotypically heterogeneous disease. Diagnosis in more or less cases can be delayed until bone marrow failure or cancer/leukemia occurs. As a result that delayed or misdiagnosis even wrong treatment received for patients with FA are not uncommon events clinically in some regions or countries due to the lack of recognition of FA from the clinicians and the limitation in testing resource in laboratory. In this review, the new concept, brief clinical characteristics, research advancing, diagnostic guidelines/differential diagnosis, laboratory testing issues and strategies on FA are discussed.

Molecular pathogenesis and clinical management of Fanconi anemia

Fanconi anemia (FA) is a rare genetic disorder associated with a high frequency of hematological abnormalities and congenital anomalies. Based on multilateral efforts from basic scientists and clinicians, significant advances in our knowledge of FA have been made in recent years. Here we review the clinical features, the diagnostic criteria, and the current and future therapies of FA and describe the current understanding of the molecular basis of the disease.

Endocrine phenotype of children and adults with Fanconi anemia

BACKGROUND

Features of Fanconi anemia (FA) are well known, including bone marrow failure, congenital anomalies such as radial anomalies, renal and ear anomalies, tracheo-esophageal fistula, imperforate anus, and elevated risk for cancer. We sought to further characterize the endocrine phenotype in children and adults with FA.

PROCEDURE

Clinically indicated endocrine evaluation data from 120 persons with FA, including 78 children (43 female) and 42 young adults (who had achieved adult height, 19 female), were entered in an institutional review board-approved database. Data were analyzed according to gender, birth weight, FA complementation group, and whether or not the patient had completed linear growth or had undergone hematopoietic cell transplant, using Wilcoxon Rank Sum or Chi-square, as appropriate.

RESULTS

Overall, 60% of children and 58% of adults with FA had short stature, 68% of children and 30% of adults had glucose intolerance, 61% of children and 37% of adults had mild hypothyroidism, and 40% of adults had evidence of hypogonadism (not possible to fully assess in children). In general, bone mineral density (BMD) was normal in adults, while BMD in children was normal when results were adjusted for bone size/thickness using height age.

CONCLUSIONS

We have evaluated in detail children and adults with FA for their growth and endocrine function. Overall, 79% of children and adults with FA had one or more endocrine abnormality.

[Fanconi anemia in 2012: diagnosis, pediatric follow-up and treatment]

Fanconi anemia (FA) is a rare genetic disease, transmitted in an autosomal recessive mode. The clinical phenotype is very broad and heterogeneous, related to the wide range of genes involved in this pathology. The classical triad of short height, physical abnormalities, and bone marrow failure is suggestive. The main physical abnormalities found involve the limbs, spinal column, skin, kidneys and urinary tract, and the ORL zone. Recent progress in molecular biology has identified 15 genes whose mutation causes FA chromosomal instability. FA is diagnosed by cytogenetic examination, then specified by molecular analysis. As FA patients may present multiorgan abnormalities and a high risk for neoplasia development, their medical follow-up has to be multidisciplinary and prolonged throughout life. The main challenges of the follow-up are patient information and education. Bone marrow failure, appearing during the first decade, requires close hematological monitoring and for severe cases requires hematopoietic stem cell transplantation, major and specific care with frequent serious complications and high mortality, but this is the only curative treatment in FA. Extrahematological care consists in screening for organ abnormalities and defects as well as monitoring precancerous lesions and tumors.

Fanconi anemia proteins and their interacting partners: a molecular puzzle

In recent years, Fanconi anemia (FA) has been the subject of intense investigations, primarily in the DNA repair research field. Many discoveries have led to the notion of a canonical pathway, termed the FA pathway, where all FA proteins function sequentially in different protein complexes to repair DNA cross-link damages. Although a detailed architecture of this DNA cross-link repair pathway is emerging, the question of how a defective DNA cross-link repair process translates into the disease phenotype is unresolved. Other areas of research including oxidative metabolism, cell cycle progression, apoptosis, and transcriptional regulation have been studied in the context of FA, and some of these areas were investigated before the fervent enthusiasm in the DNA repair field. These other molecular mechanisms may also play an important role in the pathogenesis of this disease. In addition, several FA-interacting proteins have been identified with roles in these “other” nonrepair molecular functions. Thus, the goal of this paper is to revisit old ideas and to discuss protein-protein interactions related to other FA-related molecular functions to try to give the reader a wider perspective of the FA molecular puzzle.

Bone mineral density is normal in children with Fanconi anemia

BACKGROUND

Conflicting data exist regarding whether low bone mineral density (BMD) is associated with Fanconi anemia (FA). The current study identified the frequency of low BMD in FA, expecting low BMD even in childhood and before HCT.

PROCEDURE

Thirty-seven FA patients (18 prior HCT, 19 no prior HCT), participating in an IRB-approved database, had clinical assessment of DXA of lumbar spine BMD. Four had used androgens, one later underwent HCT. Most had used glucocorticoids after HCT (prolonged in five), and one more with no HCT. BMD [in standard deviation units from mean for age (SD), gender, and ethnicity (BMD Z-score)] was then adjusted for height age, and separately for bone maturation (BA). Data were collected for height SD, pubertal stage, and duration since HCT.

RESULTS

BMD Z-score (without adjustment) was <-1 SD in half of FA children. BA-adjusted BMD Z-score was similar. (BA was not usually delayed, although most patients were short.) In contrast, height age-adjusted BMD Z-score was normal in most with FA (only below -2.0 in one child after prolonged glucocorticoids). Mean duration after HCT until DXA test was 6.2 years (median 4.2 years, range 1-18 years).

CONCLUSIONS

Children and adolescents with FA have normal BMD prior to and after HCT, when DXA results are adjusted for bone size/height age. In contrast, BA-adjustment of BMD was not useful in this population. Individual BMD results may be influenced by gonadal function, transplantation status, and prolonged glucocorticoid therapy.

The role of Fanconi anemia/BRCA genes in zebrafish sex determination

Fanconi anemia (FA) is a human disease of bone marrow failure, leukemia, squamous cell carcinoma, and developmental anomalies, including hypogonadism and infertility. Bone marrow transplants improve hematopoietic phenotypes but do not prevent other cancers. FA arises from mutation in any of the 15 FANC genes that cooperate to repair double stranded DNA breaks by homologous recombination. Zebrafish has a single ortholog of each human FANC gene and unexpectedly, mutations in at least two of them (fancl and fancd1(brca2)) lead to female-to-male sex reversal. Investigations show that, as in human, zebrafish fanc genes are required for genome stability and for suppressing apoptosis in tissue culture cells, in embryos treated with DNA damaging agents, and in meiotic germ cells. The sex reversal phenotype requires the action of Tp53 (p53), an activator of apoptosis. These results suggest that in normal sex determination, zebrafish oocytes passing through meiosis signal the gonadal soma to maintain expression of aromatase, an enzyme that converts androgen to estrogen, thereby feminizing the gonad and the individual. According to this model, normal male and female zebrafish differ in genetic factors that control the strength of the late meiotic oocyte-derived signal, probably by regulating the number of meiotic oocytes, which environmental factors can also alter. Transcripts from fancd1(brca2) localize at the animal pole of the zebrafish oocyte cytoplasm and are required for normal oocyte nuclear architecture, for normal embryonic development, and for preventing ovarian tumors. Embryonic DNA repair and sex reversal phenotypes provide assays for the screening of small molecule libraries for therapeutic substances for FA.

Epidemiology of rare anaemias in Europe

Registry and epidemiological data of Rare Anaemias (RA) in Europe is in general still incomplete and/or partially documented. One important issue is the increasing prevalence of haemoglobin disorders (HD) due to migrations from high prevalence areas. The size of the problem, particularly for sickle cell disease (SCD), is already having an impact on health services in many European countries. The best known cause of rare anaemias associated with congenital haemolytic anaemia (CHA) in Europe is Hereditary Spherocytosis (HS) a red blood cell (RBC) membrane defect with a prevalence of 1 to 5 cases per 10.000 individuals. Some other causes of CHA are extremely rare and only few individual cases have been described worldwide (i.e. some RBC enzymopathies). Congenital defects of erythropoiesis are less frequent Diamond-Blackfan Anaemia (DBA) and Fanconi Anaemia (FA) exhibit a very low prevalence ranging from 4 to 7 per million live births. Congenital Dyserythropoietic Anaemia (CDA), a genetically heterogenous group, is still less frequent and exhibits a large variability of frequency depending on the European region: 0.1-3.0 cases per million births In addition many cases are known from a large autosomal dominant family in Sweden. Although incidence of Paroxysmal Nocturnal Haemoglobinuria (PNH) in Europe is still unknown, data collection from different sources has given quotes of 1 case per 100,000 individuals to 5 cases per million births.

First phase insulin release and glucose tolerance in children with Fanconi anemia after hematopoietic cell transplantation

BACKGROUND

Fanconi anemia (FA) is an autosomal and X-linked recessive disease of chromosomal instability, which results in bone marrow failure. Children with FA have been shown to have an increased risk of diabetes mellitus (DM).

PROCEDURE

A cross-sectional study of glucose and insulin metabolism was conducted in 17 children with FA who had undergone hematopoietic cell transplantation (HCT) at the University of Minnesota. First phase insulin release (FPIR) was determined by intravenous glucose tolerance test (IVGTT). Oral glucose tolerance test (OGTT), lipid panel, blood pressure, and medical history were reviewed for additional metabolic abnormalities.

RESULTS

Seventeen FA participants, median age 11.3 (range 5.5-17.6) years, were evaluated. IVGTT identified three separate groups: low FPIR, normal FPIR, and high FPIR. Those with low FPIR were more likely to have low BMI, but had normal glucose levels. Those with high FPIR, had high BMI, elevated lipids, and body fat. One patient with normal FPIR had impaired glucose tolerance and another with normal FPIR had impaired fasting glucose. No participant was diagnosed with DM by fasting glucose, 2 hr glucose during OGTT, or hemoglobin A1C.

CONCLUSIONS

The majority of children with FA had normal glucose tolerance and normal beta-cell function after HCT. Two small subsets of patients had lower than expected and higher than expected FPIR. The clinical significance of these differences is not yet known given the normal glucose tolerance and fasting glucose levels in these two groups.

Fanconi anemia and its diagnosis

Fanconi anemia (FA) is a genetically and phenotypically heterogeneous recessive disorder characterized by diverse congenital malformations, progressive pancytopenia, and predisposition to both hematologic malignancies and solid tumors. Congenital anomalies vary from patient to patient and may affect skeletal morphogenesis as well as any of the major organ systems. Although this highly variable phenotype makes accurate diagnosis on the basis of clinical manifestations difficult in some patients, laboratory study of chromosomal breakage induced by diepoxybutane (DEB) or other crosslinking agents provides a unique cellular marker for the diagnosis of the disorder either prenatally or postnatally. Diagnosis based on abnormal response to DNA crosslinking agents can be used to identify the pre-anemia patient as well as patients with aplastic anemia or leukemia who may or may not have the physical stigmata associated with the syndrome. This overview will present our current knowledge regarding the varied phenotypic manifestations of FA and procedures for diagnosis based upon abnormal DNA damage responses.

Genotype-phenotype correlations in Fanconi anemia

Although still incomplete, we now have a remarkably detailed and nuanced picture of both phenotypic and genotypic components of the FA spectrum. Initially described as a combination of pancytopenia with a limited number of physical anomalies, it was later recognized that additional features were compatible with the FA phenotype, including a form without detectable malformations (Estren-Dameshek variant). The discovery of somatic mosaicism extended the boundaries of the FA phenotype to cases even without any overt hematological manifestations. This clinical heterogeneity was augmented by new conceptualizations. There was the realization of a constant risk for the development of myelodysplasia and certain malignancies, including acute myelogenous leukemia and squamous cell carcinoma, and there was the emergence of a distinctive cellular phenotype. A striking degree of genetic heterogeneity became apparent with the delineation of at least 12 complementation groups and the identification of their underlying genes. Although functional genetic insights have fostered the interpretation of many phenotypic features, surprisingly few stringent genotype-phenotype connections have emerged. In addition to myriad genetic alterations, less predictable influences are likely to modulate the FA phenotype, including modifier genes, environmental factors and chance effects. In reviewing the current status of genotype-phenotype correlations, we arrive at a unifying hypothesis to explain the remarkably wide range of FA phenotypes. Given the large body of evidence that genomic instability is a major underlying mechanism of accelerated ageing phenotypes, we propose that the numerous FA variants can be viewed as differential modulations and compression in time of intrinsic biological ageing.

The fanconi anemia core complex acts as a transcriptional co-regulator in hairy enhancer of split 1 signaling

Mutations in one of the 13 Fanconi anemia (FA) genes cause a progressive bone marrow failure disorder associated with developmental abnormalities and a predisposition to cancer. Although FA has been defined as a DNA repair disease based on the hypersensitivity of patient cells to DNA cross-linking agents, FA patients develop various developmental defects such as skeletal abnormalities, microphthalmia, and endocrine abnormalities that may be linked to transcriptional defects. Recently, we reported that the FA core complex interacts with the transcriptional repressor Hairy Enhancer of Split 1 (HES1) suggesting that the core complex plays a role in transcription. Here we show that the FA core complex contributes to transcriptional regulation of HES1-responsive genes, including HES1 and the cyclin-dependent kinase inhibitor p21(cip1/waf1). Chromatin immunoprecipitation studies show that the FA core complex interacts with the HES1 promoter but not the p21(cip1/waf1) promoter. Furthermore, we show that the FA core complex interferes with HES1 binding to the co-repressor transducin-like-Enhancer of Split, suggesting that the core complex affects transcription both directly and indirectly. Taken together these data suggest a novel function of the FA core complex in transcriptional regulation.

Improved growth velocity during thyroid hormone therapy in children with Fanconi anemia and borderline thyroid function

BACKGROUND

Children with Fanconi anemia (FA) tend to have short stature, mild thyrotropin (TSH) elevation, and borderline low free thyroxine (FT4). Objective was to examine whether thyroid hormone therapy improves linear growth in children with FA and borderline thyroid function tests

PROCEDURE

Thyroid function tests were performed in 63 children with FA. Eight subjects participated in a random order, double-blind, cross-over treatment for 7 months with levothyroxine and for 7 months with placebo. Monitoring included growth measurements and laboratory assays at 1, 4 and 7 months of each phase. A 1 month lead in/wash out period was excluded from analysis of each treatment phase.

RESULTS

The majority (63%) of FA children had borderline thyroid function tests. All eight FA subjects enrolled in the treatment study had FT4 in the lowest third of the normal range of 0.8-1.8 ng/dL (10.3-23.2 pmol/L) [FT4 0.9 +/- 0.1 ng/dL (mean +/- SD), range 0.8-1.2 ng/dL (10.3-15.4 pmol/L)]. TSH (optimal range 0.5-3 mU/L) was borderline elevated in six of eight subjects (4.0 +/- 1.5 mU/L, 1.9-7.3 mU/L). Growth velocity was slow at baseline and improved significantly during the thyroid phase compared to the placebo phase (2.1 +/- 1.2 cm/year vs. 5.4 +/- 1.7 cm/year, P < 0.05).

CONCLUSIONS

Thyroid hormone therapy is safe and may improve linear growth velocity in children with FA who have borderline thyroid function. Subtle hypothyroidism has importance for growth in children. Whether thyroid hormone treatment improves adult height in these children remains to be elucidated.

Abnormalities in glucose tolerance are common in children with fanconi anemia and associated with impaired insulin secretion

BACKGROUND

To determine prevalence of abnormal glucose metabolism in Fanconi Anemia (FA).

PROCEDURE

Thirty-nine children with FA underwent 2-hr oral glucose tolerance test (OGTT). Reference lean adolescents (REF) were older than FA patients (mean +/- SD: FA 8.6 +/- 3.9 years, REF 19.8 +/- 0.3 years, P < 0.001), but comparable in BMI Z-scores (FA 1.25 +/- 0.58, REF -0.02 +/- 0.24; P = 0.24). Patients had normal glucose tolerance (NGT) or abnormal glucose metabolism (AGM) by American Diabetes Association Criteria. Insulinogenic index estimated beta-cell function. Insulin resistance estimation used homeostatic model assessment (HOMA-IR). Insulin secretion estimation relative to insulin sensitivity used disposition index (DI).

RESULTS

Among FA patients, 46% had AGM. Compared to REF, there were significant differences in glycemic responses (area under curve: FA-NGT 344 +/- 42, FA-AGM 596 +/- 35, REF 208 +/- 25 mM, P < 0.0001) and insulinogenic index (FA-NGT 105 +/- 29, FA-AGM 44 +/- 8, and REF 173 +/- 41 pM/mM, P < 0.05). Insulin sensitivity did not differ among NGT, AGM, and REF (HOMA-IR: FA-NGT 1.9 +/- 0.4, FA-AGM 2.2 +/- 0.5, REF 1.3 +/- 0.2, P = NS). However, DI was significantly lower in both FA groups than REF [NGT 63.6 +/- 16.5 vs. AGM 26.4 +/- 3.5 (P < 0.048); REF 132.6 +/- 24.5 (NGT and AGM vs. REF, both P < 0.0002)].

CONCLUSION

Abnormalities in glucose metabolism are frequent in young FA patients without prior diagnosis of diabetes, and are associated with marked defects in insulin secretion.

Correlation of thyroid and growth hormones to chromosomal instability in Egyptian Fanconi anemia patients

OBJECTIVE

Fanconi anemia (FA) is a rare inherited genomic instability syndrome and usually associated with endocrine dysfunctions. We aimed to assess the diagnostic standards of chromosomal instability in FA and to correlate the breakage frequency with the severity of endocrinal dysfunctions.

METHODS

Twenty seven FA patients were randomly selected from Hematology Unit of Mansoura University Children's Hospital; their mean age 8.8 yr. Sixteen normal children matched for age and sex were used as controls. Cytogenetic studies included peripheral blood lymphocyte cultures using phytohemagglutinin to obtain chromosomal spreads. Chromosomal breakage was induced by (i) Diepoxybutane 0.1 mug/ml. (ii) Mitomycin C 0.1 microg/ml. (iii) Irradiation of cultures to four radiation doses; 75, 150, 300 and 400 rads (rad1, rad2, rad3 and rad4 respectively). Chromosomal aberrations were scored from the previous 6 cultures besides a culture for spontaneous chromosomal breakage; then mean chromosomal breakage was calculated for the seven cultures. Endocrinal evaluation included quantitative determination of thyroid stimulating hormone (TSH) and tetraiodothyronine (T4), serum growth hormone (GH), insulin like growth factor-1 (IGF-1) and insulin levels.

RESULTS

Chromosomal breakage was found to be significantly higher in patients than control when induced by Diepoxybutane (p = 0.003), Mitomycin (p = 0.001), rad3 (p = 0.043) and rad4 (p = 0.001). Mean chromosomal breakage was significantly negative correlated to head circumference (r = -0.57) and GH level (r = -0.50), with no significant correlation to other hormonal parameters. Mitomycin and rad4 were found more accurate than DEB test for diagnosis of FA in suspected cases.

CONCLUSION

Correction of the frequently associated hormonal dysfunction (reduced GH and T4) should be considered in the treatment discipline of FA patients to improve their final height.

Age- and body mass index-dependent relationship between correction of iron deficiency anemia and insulin resistance in non-diabetic premenopausal women

BACKGROUND

No prospective studies have evaluated the effects of correction of iron deficiency anemia on insulin resistance in non-diabetic premenopausal women. We investigated this relationship in 54 non-diabetic premenopausal women with iron deficiency anemia.

SUBJECTS AND METHODS

All patients were treated with oral iron preparations. Insulin resistance was calculated with the Homeostasis Model Assessment formula. All patients were dichotomized by the median for age and BMI to assess how the relationship between iron deficiency anemia and insulin resistance was affected by age and BMI.

RESULTS

Although the fasting glucose levels did not change meaningfully, statistically significant decreases were found in fasting insulin levels following anemia treatment both in the younger age (<40 years) (P=0.040) women and in the low BMI (<27 kg/m2) (P=0.022) subgroups but not in the older age (>or=40 years) and the high BMI (>or=27 kg/m2) subgroups. Post-treatment fasting insulin levels were positively correlated both with BMI (r=0.386, P=0.004) and post-treatment hemoglobin levels (r=0.285, P=0.036). Regression analysis revealed that the factors affecting post-treatment insulin levels were BMI (P=0.001) and post-treatment hemoglobin levels (P=0.030).

CONCLUSION

Our results show that following the correction of iron deficiency anemia, insulin levels and HOMA scores decrease in younger and lean non-diabetic premenopausal women.