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Mitochondrial Diabetes (mitochondrial + diabetes)

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Medical Sciences100%

Selected Abstracts

Maternal transmission of diabetes

DIABETIC MEDICINE, Issue 2 2002
J. C. Alcolado
Abstract Type 2 diabetes mellitus represents a heterogeneous group of conditions characterized by impaired glucose homeostasis. The disorder runs in families but the mechanism underlying this is unknown. Many, but not all, studies have suggested that mothers are excessively implicated in the transmission of the disorder. A number of possible genetic phenomena could explain this observation, including the exclusively maternal transmission of mitochondrial DNA (mtDNA). It is now apparent that mutations in mtDNA can indeed result in maternally inherited diabetes. Although several mutations have been implicated, the strongest evidence relates to a point substitution at nucleotide position 3243 (A to G) in the mitochondrial tRNAleu(UUR) gene. Mitochondrial diabetes is commonly associated with nerve deafness and often presents with progressive non-autoimmune ,-cell failure. Specific treatment with Coenzyme Q10 or L-carnitine may be beneficial. Several rodent models of mitochondrial diabetes have been developed, including one in which mtDNA is specifically depleted in the pancreatic islets. Apart from severe, pathogenic mtDNA mutations, common polymorphisms in mtDNA may contribute to variations of insulin secretory capacity in normal individuals. Mitochondrial diabetes accounts for less than 1% of all diabetes and other mechanisms must underlie the maternal transmission of Type 2 diabetes. Possibilities include the role of maternally controlled environments, imprinted genes and epigenetic phenomena. [source]

Islet autoimmunity and genetic mutations in Chinese subjects initially thought to have Type 1B diabetes

DIABETIC MEDICINE, Issue 1 2006
D. Zhang
Abstract Aims To explore the contribution of islet autoimmunity and genetic mutations in Chinese patients initially thought to have Type 1B diabetes. Methods A group of 33 Chinese patients with newly diagnosed Type 1B diabetes, were identified by the absence of autoantibodies to glutamic acid decarboxylase (GAD), IA-2, insulin, thyroid globulin or thyroid peroxidase, or high-risk HLA-DQ haplotypes. The cohort was further characterized by measurement of autoantibodies to carboxypeptidase H (CPH) and SOX13 using radioligand assays, and testing for genetic mutations associated with MODY3/MODY6 and mitochondrial diabetes. Mutations of HNF-1, (MODY3) and neuroD1/,2 (MODY6) genes were screened using the single-strand conformation polymorphism (SSCP) technique and sequencing. Mitochondrial DNA mutations were analysed with polymerase chain reaction,restriction fragment length polymorphism (PCR-RFLP). Results Within the cohort, we found one patient with a novel mutation, R321H (CGC,CAC) in exon 5 of the HNF-1, gene, one with ND1 mt3316 G,A mutation in mitochondrial DNA, five with Ala45Thr polymorphisms in the neuroD1/,2 gene, and two patients with autoantibodies to SOX13. Conclusions Some of the Chinese patients originally thought to have Type 1B diabetes do have other evidence of islet autoimmunity and genetic mutations involved in the underlying aetiology. This suggests that more rigorous screening for these conditions is needed before classifying subjects as having Type 1B diabetes. [source]

Maternal transmission of diabetes

DIABETIC MEDICINE, Issue 2 2002
J. C. Alcolado
Abstract Type 2 diabetes mellitus represents a heterogeneous group of conditions characterized by impaired glucose homeostasis. The disorder runs in families but the mechanism underlying this is unknown. Many, but not all, studies have suggested that mothers are excessively implicated in the transmission of the disorder. A number of possible genetic phenomena could explain this observation, including the exclusively maternal transmission of mitochondrial DNA (mtDNA). It is now apparent that mutations in mtDNA can indeed result in maternally inherited diabetes. Although several mutations have been implicated, the strongest evidence relates to a point substitution at nucleotide position 3243 (A to G) in the mitochondrial tRNAleu(UUR) gene. Mitochondrial diabetes is commonly associated with nerve deafness and often presents with progressive non-autoimmune ,-cell failure. Specific treatment with Coenzyme Q10 or L-carnitine may be beneficial. Several rodent models of mitochondrial diabetes have been developed, including one in which mtDNA is specifically depleted in the pancreatic islets. Apart from severe, pathogenic mtDNA mutations, common polymorphisms in mtDNA may contribute to variations of insulin secretory capacity in normal individuals. Mitochondrial diabetes accounts for less than 1% of all diabetes and other mechanisms must underlie the maternal transmission of Type 2 diabetes. Possibilities include the role of maternally controlled environments, imprinted genes and epigenetic phenomena. [source]

West syndrome and mitochondrial diabetes: relationship or coincidence?

CLINICAL ENDOCRINOLOGY, Issue 1 2002
B. Bouhanick
Summary West syndrome occurs in infancy and in early childhood. It is characterized by intractable seizures occurring almost daily, severe psychomotor retardation, poor prognosis and EEG abnormalities, known as hypsarrhythmia. We report here the case of a 28-year-old patient, who was diagnosed with West syndrome when he was 8 months old and with diabetes mellitus when he was 25 years old. Sequencing analyses and restriction analyses were suggestive of mitochondrial diabetes. Four years after the diagnosis of diabetes, this patient's diabetes is still controlled by diet and biguanides. [source]