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.