Detección y diagnóstico molecular de un nuevo caso de analbuminemia congénita / Detection and molecular diagnosis of a new case of congenital analbuminaemia

INTRODUCCIÓN Y OBJETIVOS: La analbuminemia congénita (AAC) (MIM #616000) es una enfermedad autosómica recesiva (prevalencia <1/106) causada por defectos en el gen ALB que implican la ausencia o marcada disminución de la albuminemia. En este artículo, describimos un caso de AAC detectado en nuestro hospital. MATERIAL Y MÉTODOS: Mujer de 42 años con hipoproteinemia e hipoalbuminemia de causa no filiada. El estudio bioquímico se realizó siguiendo las técnicas y los controles de calidad habituales de nuestro laboratorio: albuminemia (colorimetría y nefelometría); electroforesis de proteínas (capilar y gel de agarosa) y análisis molecular del gen ALB (extracción de ADN y amplificación PCR de los 14 exones codificantes más regiones intrónicas adyacentes y secuenciación Sanger). RESULTADOS: Descartadas las causas más frecuentes de hipoalbuminemia, se confirmó la analbuminemia por electroforesis y nefelometría. El estudio molecular del gen ALB evidenció la presencia de la variante c.1289+1G>A (variante Guimarães) en homozigosis. CONCLUSIONES: Este es el primer caso confirmado mediante estudio molecular de AAC en España. La paciente presenta la variante Guimarães descrita previamente en otros 4 pacientes en el mundo

INTRODUCTION AND OBJECTIVES: Congenital analbuminaemia (CCA) (MIM #616000) is an autosomal recessive disorder (prevalence < 1/106) caused by defects in the ALB gene leading to absence or severe reduction of albuminaemia. This paper describes a case of CCA detected and diagnosed in our hospital. MATERIALS AND METHODS: A 42-year old woman showing hypoproteinaemia and hypoalbuminaemia of unknown aetiology. Biochemical study was performed according to routine quality controlled analytical procedures: Albuminaemia (colorimetric and nephelometric methods). Protein electrophoresis (capillary and agarose gel). Molecular study of the ALB gene: DNA extraction, PCR amplification of the 14 coding exons plus adjacent intron regions and Sanger sequencing. RESULTS: After discarding the most common causes of hypoalbuminaemia, the analbuminaemia was confirmed by nephelometry and protein electrophoresis. The proband was found to be homozygous for molecular defect in the ALB gene: variant c.1289+1G>A previously reported as Guimarães variant. CONCLUSIONS: This is the first case of CCA confirmed by molecular study in Spain. The proband shows the Guimarães variant previously described in 4 patients worldwide

Detection and molecular diagnosis of a new case of congenital analbuminaemia. / Detección y diagnóstico molecular de un nuevo caso de analbuminemia congénita.

INTRODUCTION AND OBJECTIVES: Congenital analbuminaemia (CCA) (MIM #616000) is an autosomal recessive disorder (prevalence < 1/106) caused by defects in the ALB gene leading to absence or severe reduction of albuminaemia. This paper describes a case of CCA detected and diagnosed in our hospital. MATERIALS AND METHODS: A 42-year old woman showing hypoproteinaemia and hypoalbuminaemia of unknown aetiology. Biochemical study was performed according to routine quality controlled analytical procedures: Albuminaemia (colorimetric and nephelometric methods). Protein electrophoresis (capillary and agarose gel). Molecular study of the ALB gene: DNA extraction, PCR amplification of the 14 coding exons plus adjacent intron regions and Sanger sequencing. RESULTS: After discarding the most common causes of hypoalbuminaemia, the analbuminaemia was confirmed by nephelometry and protein electrophoresis. The proband was found to be homozygous for molecular defect in the ALB gene: variant c.1289+1G>A previously reported as Guimarães variant. CONCLUSIONS: This is the first case of CCA confirmed by molecular study in Spain. The proband shows the Guimarães variant previously described in 4 patients worldwide.