| Geno
 | 
Mag
 | 
Summary
 | 
| (C;C)
 | 
1.25
 | 
GSTM1*1 status
 | 
| (C;T)
 | 
1.25
 | 
GSTM1*1 status
 | 
| (T;T)
 | 
1.25
 | 
Common in Caucasians; GSTM1*0/0 null status
 | 
 
Although located 11kb away from it, rs366631 is effectively a pseudo-SNP tagging the status of the GSTM1 gene, due to the nature of the duplications and deletions in this part of chromosome 1.[PMID 18948376
]
In typical microarray-based genotyping results, the correspondence between the rs366631 call and GSTM1 allele status is the following:
- rs366631(T;T): GSTM1*0/0, i.e. GSTM null allele (double deletion)
 
- rs366631 (C;T) and (C;C): GSTM1*1, i.e. at least one functional GSTM1 gene copy is present
 
The GSTM1*0/0 null phenotype has a frequency of greater than 50% among Caucasian, Chinese, and Indian populations, and sporadic reports over the years (many based on rather small sample sizes) indicate that it may be a slight risk factor for certain cancers based on increased sensitivity to particular chemical carcinogens.
| OMIM | 138350 | 
| Desc | GLUTATHIONE S-TRANSFERASE, MU-1; GSTM1 | 
| Variant |  | 
| Related | also | 
 
[PMID 18496134
] Identification of genetic variants and gene expression relationships associated with pharmacogenes in humans.
[PMID 18948376
] Population-specific GSTM1 copy number variation.