This variant was discovered through sequencing exon 1 in mannose binding protein deficient Ghanian newborns where 10 newborns homozygous for this variant has no detectable levels. The frequencies were 0.29 (Ghanian adult), 0.23 (Ghanian newborn). Similar to the G54D mutation (0.17, British Caucasian and 0.11 Hong Kong), this variant disrupts the secondary structure of the protein, and is predicted to reduce the immune response to Mannose-rich organisms in infancy.
A study of patients with suspected immunodeficiency found a higher number of homozygous and compound heterozygous patients with abnormal mannan-binding protein (MBP) alleles (variants B, C, and D). In the case group of 229 patients, none were homozygous for C and one was compound heterozygous for B/C. No patients in the control population of 123 controls were homozygous or compound heterozygous for this allele.
In a study of meningcoccal susceptibility in a British population of children, patients were assayed for abnormal variants of MBL2. Of 266 patients, none were homozygous for G57E and one was compound heterozygous for G57E and R52C. Of 382 controls, one was homozygous for G57E and two were compound heterozygous. Although the paper supports pathogenicity for R52C and G54D variants, the evidence does not seem to support this particular variant.
Authors screen for MBL2 polymorphisms in patients with recurrent vaginal infections and find no significant differences between the groups.
In a study of 1019 Canadians with cystic fibrosis for complex gene interactions leading to increased lung disease, low MBL2 levels (caused by this variant and others) were significantly associated with earlier onset of lung infection.