Table II.
Number of CRIM-negative and CRIM-positive patients with different types of GAA gene mutations.
| Type of mutations | Number of CRIM-negative patients | Number of CRIM-positive patients |
|---|---|---|
| Two predicted null allelesa | 44 | 1b |
| Homozygous premature stop codon in last exon | 0 | 1c |
| At least one missense or in frame deletion | 0 | 81d |
| Homozygous initiator methionine mutation | 1e | 0 |
| Homozygous splice site mutation | 4 | 3 |
| Compound heterozygote splice site/null mutation | 3 | 2 |
| Total patients | 52 | 88 |
a
Null allele = nonsense or frame shift mutation resulting in premature termination codon in any exon but the last, or multi-exon deletion.
b
Compound heterozygote for c.1165delG (p.Glu389ArgfsX3) and c.2560C>T (p.Arg854X)
c
Homozygous for p.Gln914ProfsX30 which results in a premature stop codon in the last exon of the GAA gene
d
Two missense alleles (n=39), one missense and one null allele (n=31), one missense and one splice site mutation (n=4), one missense and one in frame exon 18 deletion (n=3), exon 18 deletion and null allele (n=2), homozygous exon 18 deletion (n=1), and small in frame deletion and null allele (n=1).
e
Homozygous for c.1A>G (p.Met1?).