Novel nonsense mutation causes analbuminemia in a Moroccan family.

We describe a novel molecular defect causing analbuminemia in a 5-year-old girl, the first child of a couple from El Jadida, Morocco.In this study, we analyzed all 14 exons of the human serum albumin gene and the flanking intron regions, and heteroduplex analysis revealed the mismatch produced by a single-base insertion. This result is in agreement with the view that the differential separation of heteroduplexes and homoduplex DNA is greater when the sequence difference is an insertion or a deletion compared with a single-base substitution. Digestion of the PCR products with restriction enzymes improved the sensitivity of SSCP analysis, and the G-to-T substitution responsible for the analbuminemic trait was identified. Many factors are known to affect the reproducibility of SSCP analysis by slab gels, including temperature and DNA quantity and purity, and might explain the observation that no clear band shift was detected in the DNA samples from the heterozygous parents.