ABSTRACT
Resumen El déficit de succínico semialdehído deshidrogenasa es una enfermedad rara cuya alteración en la vía catabólica del ácido aminobutírico (principal neurotransmisor del sistema nervioso central) impide el paso de ácido succínico semialdehído a ácido succínico, condicionando un aumento de ácido 4 hidroxibutírico en líquido cefalorraquídeo y plasma, lo que permite la detección de la enfermedad. La clínica es muy inespecífica, pudiendo presentar desde retraso psicomotor, hipotonía, convulsiones y ataxia no progresiva, hasta trastornos de conducta con crisis de ansiedad y rasgos autistas. Los hallazgos a nivel electroencefalográfico incluyen enlentecimiento del ritmo de base, con descargas epileptiformes focales o generalizadas. En la neuroimagen, en tanto, pueden hallarse frecuentemente hiperintensidades bilaterales y simétricas en T2, a nivel del núcleo pálido. Si bien el tratamiento con vigabatrina teóricamente inhibe la formación de succínico semialdehído con la consecuente reducción de los niveles de ácido 4 hidroxibutírico, no existe al momento actual un tratamiento efectivo para todos los casos. El principal objetivo de este artículo es presentar un paciente con deficiencia de succínico semialdehído deshidrogenasa, debido a su excepcionalidad, con solamente 350 casos identificados en el mundo, siendo el primer caso diagnosticado en Uruguay.
Summary Succinic semialdehyde dehydrogenase deficiency is a rare disorder of the catabolic pathway of gamma-aminobutyric acid, the major central nervous system inhibitory neurotransmitter. Because of such deficiency, transamination of gamma-aminobutyric acid to succinic semialdehyde is shunted towards the production of 4-hydroxybutyric acid, a neurotoxic metabolite which becomes abundant in physiologic fluids which allows the detection of the disorder. Clinical features are not specific and consist of psychomotor retardation, seizures, hypotonia and non progressive ataxia. Electroencephalographic finding include background slowing and generalized or focal epileptiform discharges. Magnetic resonance imaging reveals in most of the cases, increased T2-weighted signal of the globus pallidi bilaterally and symmetrically. Eventhough vigabatrin should theoretically inhibit the formation of succinic semialdehyde and therefore 4-hydroxybutyric acid, to date there is no effective treatment for succinic semialdehyde dehydrogenase deficiency. Due to its uniqueness, the main objective of this article is to present a patient with succinic semialdehyde dehydrogenase deficiency, with only 350 cases identified worldwide.
ABSTRACT
By studying 908 males from 33 locations of Europe, North Africa and West Asia, the variation of two Y-linked dinucleotide microsatellites was analyzed within three major chromosomal frames defined by mutations that are in or approach the condition of non-recurrence. Among the 223 haplotypes found, we selected a set of the ten most common haplotypes, representing 47.6% of the entire sample. We observed that they detect most of the information on inter-population differences. We calculated partial regression coefficients for haplotype frequencies as a function of latitude and longitude of the sampling locations and showed that some of them are distributed according to a cline. Furthermore, the incidence of the selected haplotypes was heterogenous, denoting the extremely high structuring of populations. These results indicate that Y chromosomal types defined by these markers here described can be considered optimal for population studies also because reliable frequency estimates can be obtained in small samples.