Defects in the AGXT gene mapped to chromosome 2q37.3 cause primary
hyperoxaluria type 1
(PH1), one of the inherited disorders of endogenous oxalate overproduction.
In order to identify
diagnostically useful linkage markers in this region of chromosome 2 we
have typed three
microsatellite loci mapping to the q37 region of chromosome 2 in 192
individuals from 30 families.
They were additionally studied for mutations and polymorphisms in the
AGXT gene. Maximum lod
scores of 29·1, 22·8 and 15·8 were obtained for
D2S140, D2S125 and D2S395 respectively at
recombination fractions (theta) of 0·001, 0·015 and 0·02.
Confidence intervals for recombination as
determined by the ‘lod-1 rule’ were 0·015, 0·05
and
0·06. Three recombinants were identified between
AGXT and D2S125/D2S395, whereas no recombination between AGXT and
D2S140 was observed.
These data allow the calculation of the risk of incorrect prenatal
diagnosis of PH1 based solely on
linkage analysis with these extragenic markers.