A new frequent allele is the missing link in the structural polymorphism of the human mannan-binding protein.
Human mannan-binding protein (MBP) is a serum lectin participating in the innate immune defence. Low MBP concentrations are explained by the dominant action of a point mutation at codon 54 of the MBP gene in Eskimos, partially in Caucasians, but not in Africans. A previously described point mutation at codon 57 was very frequent (0.23) in East Africans, low in Caucasians (0.02), and absent in Eskimos. The African population only conformed to Hardy-Weinberg expectation when assuming the existence of an unknown allele, which was subsequently found as a point mutation at codon 52. This allele appeared with a relatively high frequency (0.05) in both Africans and Caucasians, but was absent in Eskimos. Hardy-Weinberg equilibrium is now seen in the investigated ethnic groups. All cases of MBP deficiency may be explained by these three variants.
Madsen
H O
HO
Department of Clinical Immunology, Righospitalet, Copenhagen N, Denmark.
Garred
P
P
Kurtzhals
J A
JA
Lamm
L U
LU
Ryder
L P
LP
Thiel
S
S
Svejgaard
A
A
D000483:Alleles; D044466:Asian People / Q000235:genetics; D001483:Base Sequence; D044383:Black People / Q000235:genetics; D002352:Carrier Proteins / Q000097:blood / Q000235:genetics*; D037222:Collectins; D003718:Denmark / Q000208:ethnology; D005787:Gene Frequency; D005838:Genotype; D006116:Greenland / Q000208:ethnology; D006801:Humans; D004930:Inuit / Q000235:genetics; D007630:Kenya / Q000208:ethnology; D008969:Molecular Sequence Data; D011110:Polymorphism, Genetic; D012689:Sequence Homology, Nucleic Acid; D044465:White People / Q000235:genetics
D002352:Carrier Proteins; D037222:Collectins