CATSPER2, a human autosomal nonsyndromic male infertility gene.
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In the course of positional cloning of the Congenital Dyserythropoietic Anemia type I (CDAI) [MIM 224120] gene on 15q15.1-15.3, we examined a family of French origin, in which the propositus suffered from asthenoteratozoospermia and nonsyndromic deafness in addition to CDAI. Two of his brothers had a similar phenotype. All three siblings were homozygous carriers of the CDA1 mutation as well as of a distally located approximately 70 kb deletion of the proximal copy of a 106 kb tandem repeat on chromosome 15q15. These repeats encode four genes whose distal copies may be considered pseudogenes. Lack of functional stereocilin and CATSPER2 (a voltage-gate cation channel expressed specifically in spermatozoa) may explain the observed deafness and male infertility phenotypes. To the best of our knowledge, the involvement of CATSPER2 in asthenoteratozoospermia is the first description of a human autosomal gene defect associated with nonsyndromic male infertility. (+info)
Congenital dyserythropoiesis and progressive alopecia in Polled Hereford calves: hematologic, biochemical, bone marrow cytologic, electrophoretic, and flow cytometric findings.
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Congenital dyserythropoiesis with dyskeratosis is a slow, progressive, and often fatal disease in Polled Hereford calves. Affected calves have a macrocytic normochromic anemia with a mild reticulocytosis. Studies indicate that calves are hyperferremic with increased saturation of serum total iron binding capacity, which rules out iron deficiency as a cause. Other secondary causes of dyserythropoiesis, including cobalamin and folate deficiencies, are unlikely because serum cobalamin and folate levels of affected calves were normal. Virus isolation was negative, and failure to identify bovine retroviral antigens or antibodies from several calves suggested that viral agents were not involved. Bone marrow cytologic findings were similar to those in congenital hereditary dyserythropoiesis in humans and included occasional multinucleate cells, internuclear chromatin bridging between nuclei of partially divided cells, and, more frequently, irregular nuclear shapes and chromatin patterns. DNA content and cell cycle distribution of erythroid cells appeared normal, and no electrophoretic abnormalities were detected in erythrocyte membrane proteins. The Polled Hereford syndrome is similar in many ways to type I congenital dyserythropoiesis in humans and may be an appropriate biomedical model for studying erythroid proliferation during dyserythropoiesis. (+info)
Differential requirements for the activation domain and FOG-interaction surface of GATA-1 in megakaryocyte gene expression and development.
(19/81)
GATA1 is mutated in patients with 2 different disorders. First, individuals with a GATA1 mutation that blocks the interaction between GATA-1 and its cofactor Friend of GATA-1 (FOG-1) suffer from dyserythropoietic anemia and thrombocytopenia. Second, children with Down syndrome who develop acute megakaryoblastic leukemia harbor mutations in GATA1 that lead to the exclusive expression of a shorter isoform named GATA-1s. To determine the effect of these patient-specific mutations on GATA-1 function, we first compared the gene expression profile between wild-type and GATA-1-deficient megakaryocytes. Next, we introduced either GATA-1s or a FOG-binding mutant (V205G) into GATA-1-deficient megakaryocytes and assessed the effect on differentiation and gene expression. Whereas GATA-1-deficient megakaryocytes failed to undergo terminal differentiation and proliferated excessively in vitro, GATA-1s-expressing cells displayed proplatelet formation and other features of terminal maturation, but continued to proliferate aberrantly. In contrast, megakaryocytes that expressed V205G GATA-1 exhibited reduced proliferation, but failed to undergo maturation. Examination of the expression of megakaryocyte-specific genes in the various rescued cells correlated with the observed phenotypic differences. These studies show that GATA-1 is required for both normal regulation of proliferation and terminal maturation of megakaryocytes, and further, that these functions can be uncoupled by mutations in GATA1. (+info)
Homozygous mutations in LPIN2 are responsible for the syndrome of chronic recurrent multifocal osteomyelitis and congenital dyserythropoietic anaemia (Majeed syndrome).
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BACKGROUND: Majeed syndrome is an autosomal recessive, autoinflammatory disorder characterised by chronic recurrent multifocal osteomyelitis and congenital dyserythropoietic anaemia. The objectives of this study were to map, identify, and characterise the Majeed syndrome causal gene and to speculate on its function and role in skin and bone inflammation. METHODS: Six individuals with Majeed syndrome from two unrelated families were identified for this study. Homozygosity mapping and parametric linkage analysis were employed for the localisation of the gene responsible for Majeed syndrome. Direct sequencing was utilised for the identification of mutations within the genes contained in the region of linkage. Expression studies and in silico characterisation of the identified causal gene and its protein were carried out. RESULTS: The phenotype of Majeed syndrome includes inflammation of the bone and skin, recurrent fevers, and dyserythropoietic anaemia. The clinical picture of the six affected individuals is briefly reviewed. The gene was mapped to a 5.5 cM interval (1.8 Mb) on chromosome 18p. Examination of genes in this interval led to the identification of homozygous mutations in LPIN2 in affected individuals from the two families. LPIN2 was found to be expressed in almost all tissues. The function of LPIN2 and its role in inflammation remains unknown. CONCLUSIONS: We conclude that homozygous mutations in LPIN2 result in Majeed syndrome. Understanding the aberrant immune response in this condition will shed light on the aetiology of other inflammatory disorders of multifactorial aetiology including isolated chronic recurrent multifocal osteomyelitis, Sweet syndrome, and psoriasis. (+info)
A case of congenital dyserythropoietic anemia type II associated with hemochromatosis.
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A 54-year-old woman with anemia, diabetes mellitus and liver dysfunction was admitted to our hospital. Numerous binucleated erythroblasts in the bone marrow, a positive serum acidified test, and the presence of anti I and anti i antigens on the surface of her erythrocytes indicated that she had congenital dyserythropoietic anemia (CDA) Type II. Hemochromatosis was confirmed by a liver biopsy. This case is a sibling of a patient with CDA Type II reported by Omine et al in 1981 (Acta Haematol Jpn 44:1). They report that no physical or hematological abnormalities were found when she was examined at the age of 29 years. Twenty-five years later, she developed CDA Type II and hemochromatosis. This case indicates that long-term observation of the family members of a patient with CDA Type II is necessary. (+info)
Congenital dyserythropoietic anemia type I (CDA I): molecular genetics, clinical appearance, and prognosis based on long-term observation.
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Congenital dyserythropoietic anemia type I (CDA I) is a rare autosomal recessive disorder with ineffective erythropoiesis and iron overloading. More than 100 cases have been described, but with the exception of a report on a large Bedouin tribe, these reports include only small numbers of cases, and no data on the lifetime evolution of the disease are available. Since 1967, we have been able to follow 21 cases from 19 families for up to 37 years. Twenty-one patients with a confirmed diagnosis of CDA I exhibited chronic macrocytic anemia of variable severity, requiring regular red cell transfusions only in 2 individuals. Four developed gallstones before the age of 30 years. Fifteen of 16 cases alive at the time of analysis showed mutations of at least one allele from exons 6 to 28 within CDAN1. Iron overloading is to be expected in all patients. In 9 patients, iron depletion was started between the ages of 7 and 36 years. Splenectomy, which was performed in 7 patients, did not result in improvement of hemoglobin values. Five patients were treated with interferon alpha-2a, and all responded with a rise in hemoglobin concentration of between 25 and 35 g/L (2.5 and 3.5 g/dL) starting within 4 weeks. (+info)
Ultrastructural findings in congenital anemia, dyskeratosis, and progressive alopecia in Polled Hereford calves.
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Ultrastructural evidence of dyserythropoiesis was found in ten calves (ages 1 to 16 months) previously diagnosed as having congenital anemia, dyskeratosis, and progressive alopecia. Morphologic abnormalities found in erythroid precursors of all calves were associated with the nucleus. Rubriblast nuclei were irregular with numerous blebs, indentations, and deep clefts. Elongated blebs appeared as satellite nuclei in some sections. Nuclear membranes had numerous defects or gaps, which were frequently present in, but not limited to, recently divided cells. Cytoplasmic material could be found within these gaps and extending into the nucleus. Rubricytes had chromatin that was abnormally condensed and hyperosmiophilic, with numerous translucent vacuoles present. Binucleate rubricytes occurred frequently in affected calves. These changes resemble those of type I congenital dyserythropoiesis in human beings, and we suggest congenital anemia, dyskeratosis, and progressive alopecia of Polled Hereford calves as the appropriate diagnostic terms to describe this disease. (+info)
A case of successful management with splenectomy of intractable ascites due to congenital dyserythropoietic anemia type II-induced cirrhosis.
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The congenital dyserythropoietic anemias comprise a group of rare hereditary disorders of erythropoiesis, characterized by ineffective erythropoiesis as the predominant mechanism of anemia and by characteristic morphological aberrations of the majority of erythroblasts in the bone marrow. Congenital dyserythropoietic anemia type II is the most frequent type. All types of congenital dyserythropoietic anemias distinctly share a high incidence of iron loading. Iron accumulation occurs even in untransfused patients and can result in heart failure and liver cirrhosis. We have reported about a patient who presented with liver cirrhosis and intractable ascites caused by congenital dyserythropoietic anemia type II. Her clinical course was further complicated by the development of autoimmune hemolytic anemia. Splenectomy was eventually performed which achieved complete resolution of ascites, increase of hemoglobin concentration and abrogation of transfusion requirements. (+info)