We have determined by sequencing the allelic variation in intron 2 and 3 of
hte MICA gene for a total of 22 different alleles. Sequencing of introns w
as performed in two directions, using DNA from homozygous cell lines from f
amilies and from unrelated individuals. Intron 2 is 273 bp long and did in
the alleles investigated not reveal any length polymorphism. We found a tot
al of eight polymorphic positions which exhibit a strict biallelism, as it
is also found in the polymorphisms for exon 2, 3 and 4 of MICA. Intron 3 is
586 bp long an required an additional set of primers placed near the middl
e of this intron in order to allow a complete bidirectional sequence. In in
tron 3, a total of 10 polymorphic positions were identified. Interestingly,
we found two variants of the allele MICA*002 which are distinguished only
by one basepair difference in intron 3. The variant MICA*002A is associated
with HLA-B35 and B58, while the allele MICA*002B is associated with B38 an
d B39.