Dos hermanas con distrofia macular causada por la mutación 3243A>G del ADN mitocondrial / Two sisters with macular dystrophy caused by the 3243A>G mitochondrial DNA mutation

CASO CLÍNICO: Dos hermanas de 54 y 60 años, con antecedentes de diabetes y sordera, consultaron por disminución de la agudeza visual (AV). En la funduscopia se observaban áreas parcheadas de atrofia coriorretiniana con disposición anular alrededor de la fóvea. El estudio genético identificó la mutación heteroplásmica 3243A>G en el ADN mitocondrial, compatible con el síndrome Maternally Inherited Diabetes and Deafness (MIDD) o enfermedad de Ballinger-Wallace. Discusión: El hallazgo de tales alteraciones maculares características, especialmente si se acompaña de diabetes mellitus y sordera, nos debe indicar la realización de un cribado del genoma mitocondrial para identificar este inusual síndrome

CASE REPORT: Two sisters of 54 and 60 years old, with a history of diabetes and deafness, consulted for decreased visual acuity (VA). Funduscopic examination revealed patchy areas of chorioretinal atrophy with annular arrangement around the fovea. Genetic study identified the heteroplasmic mutation 3243A>G in mitochondrial DNA, which supports syndrome maternally inherited diabetes and deafness (MIDD) or Ballinger-Wallace disease. DISCUSSION: The finding of such macular disorders, especially in the presence of diabetes mellitus and deafness, should suggest the performing of a mitochondrial genome screening to identify this unusual syndrome

Impaired peripheral glucose sensing in F1 offspring of diabetic pregnancy

Maternal diabetes can induce permanent changes in glucose homeostasis that can occur pre- and post-natal and leads to type 2 diabetes in adulthood. This study aimed to investigate the effect of maternal diabetes on the F1 offspring peripheral glucose sensing and mitochondrial biogenesis in an attempt to clarify the mechanism of diabetogenic programming. Two groups of female Wistar rats were used (diabetic and control); diabetes was neonatally induced by STZ injection to 5-day old rats. After the pregnancy and delivery, the offspring were weaned to control diet or high-caloric (HCD) diet and followed up for 30 weeks. Every 5 weeks, OGTT was constructed, and serum and tissues were obtained for the assessment of mTFA, mtDNA, UCP2, insulin receptor (IR), phospho-insulin receptor (phospho-IR), and GLUT4. The result indicated impaired glucose tolerance (IGT) and insulin resistance in the offspring under control diet at the 15th week of age and thereafter while those offspring under HCD showed IGT at 10th week, and diabetes was evidenced at the 25th week of age. This defect in glucose metabolism was preceded by impairment in the phosphorylation of IR and decreased IR and Glut4 that cause impaired glucose sensing together with inhibited mitochondrial biogenesis in muscle and adipose tissues. This study indicated that maternal diabetes caused impaired glucose sensing and insulin resistance in the peripheral tissues and caused change in the expression of genes involved in mitochondrial biogenesis and function. Post-natal feeding with HCD may accelerate these changes. Male F1 offspring appears to be more sensitive than females for fetal programming of T2D (AU)

Caracterización de una posible nueva mutación patológica en el gen mitocondrial ND1 asociada a neuropatía óptica hereditaria de Leber / No disponible

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Aspectos actuales de los trastornos de la cadena respiratoria mitochondrial durante la infancia y adolescencia / Current aspects of mitochondrial respiratory chain disorders during childhood and adolescence

Se realiza una revisión actualizada sobre los aspectos genéticos, bioquímicos, clínicos, diagnósticos y terapéuticos básicos de las citopatías mitocondriales debidas a deficiencia de los complejos de la cadena respiratoria mitocondrial y con expresividad clínica durante la infancia y/o adolescencia. A efectos de exposición se sistematizan los aspectos clínicos en dos amplios grupos o apartados: citopatías mitocondriales debidas a alteraciones del ADN mitocondrial (ADNmt) y citopatías mitocondriales secundarias a alteraciones del ADN nuclear (ADNn), aportando algunas reflexiones sobre la importancia de estos procesos en este margen de edad (AU)

We carry out a review of the current basic genetic, biochemical, clinical, diagnostic and therapeutic aspects of mitocondrial cytopathies due to deficiencies in the mitocondrial cytopathies due to deficiencies in the mitocondrial respiratory chain complexes, which appear clinically during childhood and/or adolescence. The clinical description has been divided into two groups: mitochondrial cytopathies secondary to alterations of mitochondrial DNA (mtDNA) and mitochondrial cytopathies secondary to alterations of the nuclear DNA (nDNA) and we considering about the importance of such conditions at this age (AU)