Biomedical subjects

J Montoya

Publications and source records attributed to J Montoya.

96 records · Page 6Linked to original sources

PubMedDate not supplied

[Familiar chronic progressive external ophthalmoplegia of mitochondrial origin].

INTRODUCTION: The syndrome of chronic progressive external ophthalmoplegia (CPEO) is a mitochondrial disease characterized by ptosis and ophthalmoplegia has that has been associated to the presence of large deletion, single or multiple, in the mitochondrial DNA of skeletal muscle. CASE REPORT: We report a familiar case of chronic progressive external ophthalmoplegia of maternal inheritance that began at birth, and developed with slow progression but with no multisystemic involvement. Non of the affected individuals had ragged-red fibers in skeletal muscle. Genetic analysis of mitochondrial DNA revealed the presence of a single deletion of 4,977 bp that encompasses the nucleotide positions 8,482 to 13,460, flanked by a direct repeat sequence. CONCLUSIONS: The amount of deleted mitochondrial DNA (15%) in this patient's muscle suggests, even if the percentage of the mutation is low, that this deletion is the molecular cause of the phenotypic presentation of this patient. This is one of the few cases described in the literature of CPEO maternally inherited.

Adolescent↗

PubMedDate not supplied

[A patient with bilateral lesion in the striatum and slowly progressive dystonia secondary to T14487C mutation in the ND6 gene of complex I of the mitochondrial respiratory chain].

INTRODUCTION: A large number of diseases present as bilateral striatal lesion syndrome (BSLS). Clinical manifestations, course and prognosis of these diseases are extremely variable. On the basis of their evolutive course, they can be separated into two major groups: acute, which include toxic, infectious or parainfectious causes, and subacute or chronic, in which inborn errors of metabolism, especially mitochondrial disorders, are the main causes. CASE REPORT: We report a detailed clinical follow-up of a 18 years old Caucasian male who, at the age of four, presented with BSLS. A respiratory chain defect was suspected on the basis of slowly progressive dystonia and cognitive impairment, changes in serial MRI studies, and the finding of 'trabecular fibers' as well as a 50% decrease of the complex I activity in striated-skeletal muscle specimen. Blood, urine and CSF markers classically associated with respiratory chain diseases were normal. Molecular studies identified a new pathogenetic mutation (T14487C) in the mitochondrial ND6 gene of the respiratory chain complex I. CONCLUSION: Mitochondrial metabolism disorders should be ruled out in patients presenting with a subacute or chronic form of BSLS even in the absence of other common mitochondrial disease markers.

Adolescent↗

PubMedDate not supplied

[Evolution until death of two members of a family with A3243G mutation and MELAS phenotype versus diabetes mellitus].

INTRODUCTION: The A3243G gene tRNALeu(UUR) mutation has different phenotypic expressions. The clinical outcome and survival of each phenotype are mostly unknown. We followed-up two of three family members, carriers of the A3243G mutation, until their death. CLINICAL CASE: The proband case had MELAS (mitochondrial myopathy, encephalopathy, lactacidosis, stroke) phenotype. Although he presented with a stroke-like episode, he developed recurrent generalized and partial epileptic seizures without associated stroke-like episodes over time as well as slowly progressive dementia. The cognitive performance greatly worsened after a complex partial epileptic status. He died from bronchopneumonia and septic shock eleven years after diagnosis. His sister remains asymptomatic. His mother was diagnosed of diabetes mellitus and deafness when she was 53. Seventeen years later she developed a single stroke-like episode. She died one year after from acute renal failure and cardiogenic shock following sympathectomy for ischemic angiopathy. In the MELAS case neither idebenone treatment nor valproate substitution by other anticonvulsants reduced seizure frequency nor the spreading of lesions evaluated by MRI. In the phenotype with diabetes and deafness the outcome diabetes mellitus was as expected. CONCLUSIONS: In this family with A3243G mutation, the phenotype with neurosensorial deafness and diabetes mellitus seems to have longer survival than the MELAS phenotype. The cause of death in both cases was closely related to medical complications prevalent in each patient at the time of death.

Adult↗

PubMedDate not supplied

[Diseases of the human mitochondrial oxidative phosphorylation system].

AIM: The diseases of the oxidative phosphorylation system consist of a group of disorders originated by a deficient synthesis of adenosine triphosphate (ATP). These diseases are increasingly being diagnosed among patients with multisystemic disorders. Mitochondrial deoxyribonucleic acid (mtDNA) mutations are usually maternally inherited, but they also can be sporadic or secondary to nuclear mutations, that are inherited in a Mendelian mode, or due to environmental hazards. In this review we will update, from a genetic point of view, the knowledge on human mitochondrial diseases, remarking the difficulties to study these pathologies. DEVELOPMENT: To mirror these difficulties, we will use selected examples of mutations in the mitochondrial genome, and review recent advances on mitochondrial pathology due to mutations in the nuclear genes codifying for mitochondrial proteins that participate in a good performance of the oxidative phosphorylation system. CONCLUSIONS: Sequencing of the complete human mtDNA should be part of the basic profile in the study of mitochondrial diseases. Due to the increasing number of nuclear genes involved in the oxidative phosphorylation system performance, their analysis should be based on solid biochemical clues.

DNA, Mitochondrial↗

PubMedDate not supplied

[Mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS) with the A3243G mutation of the tRNALeu(UUR) gene of mtDNA in native American haplogroup B2].

INTRODUCTION: Mitochondrial encephalopathy, lactic acidosis and cerebrovascular accident syndrome (MELAS) is, from the clinical point of view, one of the best studied mitochondrial multisystemic disorders. This disease has mainly been associated to the mitochondrial desoxyribonucleic acid (mtDNA) mutation A3243G located in the tRNALeu(UUR) gene. Although a relation between European haplogroups and the presence of the 3243 mutation has not been described, nothing is known about the presence of this mutation in native American haplogroups. CASE REPORT: A 12 year-old female Mexican patient diagnosed with MELAS is reported. Besides neurological, biochemical and cytological examination, we also analyzed the particular mtDNA mutations related to MELAS and the whole genome was sequenced to determine the mitochondrial haplogroup. The A3243G mutation was detected in the patient and maternal relatives (mother and siblings, all of them asymptomatic). The genotype corresponds to the native American haplogroup B2 and contains two private non-synonymous polymorfisms. CONCLUSION: All the members of the family studied present different percentage of the A3243G mutation, being the patient who presented the highest value. The mtDNA genotype corresponds to the native American haplogroup B2 and the private polymorphisms do not confer any phenotypic modification in MELAS syndrome.

Child↗

PubMedDate not supplied

[Epidermoid carcinoma of the thyroid: a potentially curable tumor. Report of a case].

A case with squamous carcinoma of the thyroid is reported. The tumor appeared as a nodule of two cm in the right lobe. The patients was treated only with total thyroidectomy and 30 months after surgery, he remains free of disease. The histologic findings agree with the etiologic theory of a malignant transformation of metaplasic cells in these neoplasms. We think that total thyroidectomy may be curative in localized cases.

Aged↗