Genetic considerations on association between HLA and disease

Summary Blood specimens from a random sample of 981 South African Negroid females were typed electrophoretically inter alia for their G-6-PD phenotypes. The allele frequency for Gd^B and Gd^nonB was found to be 0.8126 and 0.1874 respectively. Calculating the number of individuals expected for each phenotypic class, a highly significant deviation from the Hardy-Weinberg equilibrium became manifest, i.e. there was a deficit of 24.6% of heterozygotes and an excess of 12.3% of each of the two classes of homozygotes.Several possible reasons for this discrepancy e.g. the effects of pooling sub-samples, selection and misclassifications due to insufficient staining were examined and were found not to be likely explanations for the observed phenomenon. Instead, the result is interpreted as due to only 3–4 stem cells which give rise to the haematopoetic system in man.Part of this work was presented at the biennial Congress of the Deutsche Gesellschaft für Anthropologie und Humangenetik held in Vienna, September 22–25, 1975Supported by a research fellowship (1975/76) granted by the Alexander von Humboldt-Stiftung, Bonn-Bad GodesbergSupported by the Deutsche Forschungsgemeinschaft (DFG), Bonn-Bad Godesberg     

The plasminogen polymorphism in South African Negro populations: genetics and anthropogenetics

Summary Genetic polymorphism of human plasminogen (PLG) was investigated in 1252 unrelated individuals from eight South African Bantu-speaking Negro tribes. PLG phenotypes were determined by isoelectric focusing (pH 3.5–9.5 and 5–8 gradients) of neuraminidase-treated samples and subsequent detection by caseinolytic overlay or immunoblotting with specific antibody. No significant difference in the distribution of PLG alleles among the eight ethnic groups was observed. The combined allele frequencies of the common alleles in South African Negroes were 0.6977 for PLG*A, 0.2736 for PLG*B. In addition, six rare alleles were seen: PLG*A3, *A1, *M2, *B1, *B2, *B3. The rare variant PLG*B2 was proven to segregate by autosomal Mendelian inheritance in a family. The combined frequency for the rare alleles was 0.0287. The distribution of phenotypes in the total population sample was found to be in Hardy-Weinberg equilibrium. A striking difference in PLG allele distribution between Negroes from South Africa and published Negroid frequencies from North America could be observed. This difference was also seen in comparison with Mongoloid populations; in contrast, PLG frequencies for South African Negroes were similar or almost identical to known Caucasoid distributions.     

No evidence for linkage disequilibrium between Bf and GLO in African Negroids

Summary A sample of South African Negroids (n=791) was scored for each individual's Bf and GLO phenotype. (The genes for the Bf and GLO polymorphisms are included in a known cluster of linked genes on chromosome 6.) Following a ²-test the respective two series of alleles were found to be distributed at random, i.e., there was no evidence for a linkage disequilibrium. This result is discussed in terms of the linkage relationships and map distances of the genetic markers involved.Supported by the Deutsche Forschungsgemeinschaft (DFG), Bonn-Bad GodesbergSupported by a grant from the Georg and Agnes Blumenthal-Stiftung, BerlinSupported by a research fellowship (1975/76) awarded by the Alexander von Humboldt-Stiftung, Bonn-Bad Godesberg     

The distribution of esterase D variants in different ethnic groups

Summary Blood samples collected from a number of human populations belonging to various ethnic groups were screened on cellogel for red-cell esterase D (ESD) variants. These data gathered during the present study together with those that have already appeared in the literature indicate that the common variant allele ESD ² occurs most frequently in the Mongoloid populations, least frequently in the Negroid, and with intermediate frequencies in the Caucasoids. An east to west cline was noticed in the northern populations of the Indian subcontinent; ESD ² gene frequencies in these populations were found to range between those among the Mongoloids and the Caucasoids.     

Partial monosomy 22 as the result of an unbalanced translocation 5:22 in a patient with cri-du-chat syndrome

Summary Properdin factor B phenotypes were determined in 7 Bantu speaking Negroid populations, 1 Indian, and 1 Colored population of South Africa in a total of 1258 individuals. In the Negroid populations allele frequencies were: Bf^F 0.655, Bf^S 0.282, Bf^RARE 0.063, in the Indian population: Bf^F 0.322, Bf^S 0.645, Bf^RARE 0.033, and in the Colored population: Bf^F 0.513, Bf^S 0.435, Bf^RARE 0.052. In addition, 2 so far unknown F alleles and possibly 1 new S allele were discovered.     

Oculocutaneous albinism (OCA2) in sub-Saharan Africa: distribution of the common 2.7-kb P gene deletion mutation

Oculocutaneous albinism (OCA2) is the most common autosomal recessive disorder in the South African Negroid population, occurring with a prevalence of 1/3900 individuals. The OCA2 locus, P, has been mapped to chromosome 15q11–q13 and a 2.7-kb interstitial deletion has been found to be the common mutation in Africa. This study reports the detection of the deletion allele in OCA2-affected individuals from the southern African, Zambian and Central African Republic (CAR) Negroid populations (0.77, 131/170 OCA2 chromosomes; 0.79, 11/14; 0.33, 4/12, respectively). Normally pigmented individuals from different African countries were also tested. The deletion mutation was found at a frequency of 0.013 (10/780) in the normally pigmented southern African Negroid population and at a lower frequency in individuals from central Africa (0.002; 2/834), including individuals from Zambia, Cameroon, Zaire and the CAR. The study confirms the African origin of this deletion allele. Haplotype analysis suggests that the deletion mutation probably occurred only once and that it arose before the divergence of these African populations, which is estimated to be about 2000– 3000 years ago. The unusually high frequency of OCA2 mutations, in particular the 2.7-kb deletion, suggests some selective agent or genetic drift. Received: 24 September 1996 / Revised: 8 November 1996     

Distribution of hereditary blood groups among indians in South America. VII. In Argentina

This seventh and last paper in a series on the distribution of blood groups among Indians in South America reports the findings among Amerinds in Argentina. Blood specimens were procured from putative full-bloods of the following tribes: 38 Diaguita (Calchaqui), 230 Mataco, 90 Chiriguano, 142 Choroti, 51 Toba, 120 Chané, 96 Chulupi (Ashluslay), and 178 Araucano (Mapuche). These 945 samples were tested for blood factors in the A-B-O, M-N-S-s, P, Rh-Hr, K-k, Lewis, Duffy, Kidd, and Diego systems. Serum samples were tested for haptoglobins and transferrins. Hemolysates prepared from whole blood were tested for hemoglobin types. The results are presented in tables as phenotype distribution and calculated allele frequencies. Locations of the populations from which blood samples were procured are shown on a map of North and Central Argentina. High frequencies are reported for the O allele. Allele frequencies are high also for M, s, R¹ (CDe), R² (cDE), k, Le^H and Fy. They are usually low or absent for alleles B, N, S, Mi^a, Vw, R^o (cDe), r (cde), K, Le¹, and fy. The Di allele ranged from 0.013 in the Araucano (Mapuche) to 0.192 in the Toba. Allele frequencies aberrant for Indians were observed more often in the Araucano (Mapuche) and Diaguita tribes, due probably to greater inflow of non-Indian genes into their gene pool and perhaps also to genetic drift in small inbred populations. Hp¹ allele frequencies varied from 0.43 in the Choroti to 0.80 in the Diaguita. All samples tested for transferrins except six contained the variant Tf C; the six were B₁ C present in samples from one Mataco and six Araucano persons. All the specimens tested electrophoretically for hemoglobin types contained only (A) as a major component.     

The distribution of Gc subtypes among the Mongoloid populations

The polymorphism of Gc (group-specific components) has been investigated for a series of 3,160 individual samples from 11 Mongoloid populations in Asia and North and South America by isoelectric focusing on polyacrylamide gels. The samples fall into six Gc phenotypes which can be explained by the three common alleles, Gc^1F, Gc^1S, and Gc², together with several variant phenotypes explained as the heterozygotes for the three common alleles. The distribution of Gc^1F suballele appears to be considerably different from population to population among Mongoloids, ranging from 0.105 (Machiguenga Indans, Peru) to 0.609 (Kadazan, Borneo). A clear geographic cline from Southeast Asia into South America in Gc^1F allele was observed in the populations. In general, Gc^1F allele frequencies are lower in European populations and higher in African populations. The range of variability in the Gc^1F values observed among the Asiatic populations is between the Africans and the Europeans.     

Duplications and deletions of the human IGHC locus: evolutionary implications

 A limited number of deletions and duplications within the human immunoglobulin heavy chain constant locus (IGHC) has previously been reported. We studied the IGHC locus in about 500 individuals representing three major races of human, Negroid (Gambian), Mongoloid (Japanese and Chinese), and Caucasoid (Iranian and Swedish). The haplotype frequency of duplications is highest in the Mongoloid population (22%), followed by the Caucasian (10%) and Negroid (5%) populations. The corresponding frequency of deletions are 2, 1.5, and 3.5%, respectively. New types of multiple duplications were found in this study on different genetic (H haplotype and racial) backgrounds. The most common duplication, found in all populations studied, encompasses the IGHA1-IGHE genes. The only deletion common to all racial groups is an isolated deletion of the IGHG4 gene. Our data are consistent with the hypothesis that the Caucasoid-Mongoloid group diverged from the hominoid ancestor after development of the Negroid populations, with subsequent evolution within the respective groups thereafter. Received: 14 June 1996/Revised: 2 August 1996     

Association Between the 4 bp Proinsulin Gene Insertion Polymorphism (IVS‐69) and Body Composition in Black South African Women

The objective of the study was to examine the association between a functional 4 bp proinsulin gene insertion polymorphism (IVS‐69), fasting insulin concentrations, and body composition in black South African women. Body composition, body fat distribution, fasting glucose and insulin concentrations, and IVS‐69 genotype were measured in 115 normal‐weight (BMI <25 kg/m²) and 138 obese (BMI ≥30 kg/m²) premenopausal women. The frequency of the insertion allele was significantly higher in the class 2 obese (BMI ≥35kg/m²) compared with the normal‐weight group (P = 0.029). Obese subjects with the insertion allele had greater fat mass (42.3 ± 0.9 vs. 38.9 ± 0.9 kg, P = 0.034) and fat‐free soft tissue mass (47.4 ± 0.6 vs. 45.1 ± 0.6 kg, P = 0.014), and more abdominal subcutaneous adipose tissue (SAT, 595 ± 17 vs. 531 ± 17 cm², P = 0.025) but not visceral fat (P = 0.739), than obese homozygotes for the wild‐type allele. Only SAT was greater in normal‐weight subjects with the insertion allele (P = 0.048). There were no differences in fasting insulin or glucose levels between subjects with the insertion allele or homozygotes for the wild‐type allele in the normal‐weight or obese groups. In conclusion, the 4 bp proinsulin gene insertion allele is associated with extreme obesity, reflected by greater fat‐free soft tissue mass and fat mass, particularly SAT, in obese black South African women.     

Chronotype distribution in professional rugby players: Evidence for the environment hypothesis?

Individual sport athletes have been shown to comprise unusually high proportions of morning-types (MTs) coupled with a higher prevalence of the morningness-associated PERIOD3 variable number tandem repeat (VNTR) allele, PER3⁵. The degree to which type of sport selected is influenced by either chronotype or genotype, or the extent to which sporting environment contributes to chronotype is unclear. The aim of this study was to assess chronotype and PER3 VNTR polymorphism frequencies in team sport players and non-athletic controls. South African male Super Rugby players (RUG, n = 120) and a control population of males with habitually low levels of physical activity (defined as exercise no more than twice a week; CON, n = 117) took part in this study. Participants completed the Horne–Östberg morningness–eveningness questionnaire to determine chronotype and donated buccal cell or blood samples from which PER3 VNTR genotype was established. There were more MTs in the RUG (47%) than CON group (23%, p < 0.001), more evening-types in the CON group (18%) compared to the RUG group (3%, p < 0.001), but no differences in PER3 VNTR genotype (p = 0.619) or allele (p = 0.758) frequencies. In both groups, more people carried the PER3⁴ allele (RUG: 63%, CON: 62%). Chronotype was associated with genotype in the CON (p = 0.004) but not the RUG group (p = 0.895). Unlike the individual sport endurance athletes previously studied in whom the PER3⁵ allele predominated, the PER3 VNTR genotype distribution in these team sport players was similar to that of the general population. We hypothesise that the absence of any chronotype–genotype relationship in these rugby players is because their diurnal preference is shifted towards morningness through habitual athletic behaviour.     

A human immunoglobulinIGHG3 allele (Gmb0, b1, c3, c5, u) with anIGHG4 converted region and three hinge exons

The five humanIGHG genes consist of three constant domain exons plus one of or four hinge exon(s), the quadruplicated hinge region being characteristic of theIGHG3 gene. Besides this structural difference, theIGHG genes are polymorphic, as demonstrated by the restriction fragment length polymorphism and, at the protein level, by the Gm allotypic antigenic determinants. In this paper, we report the sequence of theG3m(b0, b1, c3, c5, u) IGHG3 allele, typical of the Black African populations and of populations with Negroid admixture, found in a homozygous Tunisian designated as LAT. We demonstrate that thisG3 allele contains only three hinge exons instead of four (the probable result of an unequal crossing over) and thatIGHG3 genes with triplicated hinge exons (and therefore encoding shorter γ 3 chains) are present in healthy individuals from different populations. Moreover, we show that the LAT G3m (b0, b1, c3, c5, u) coding sequence results from the conversion, in the CH3 exon, of theG3m (b0, b1, b3, b4, b5, u, v) allele, the most frequentIGHG3 gene in the Negroid populations, by the homologous region of aIGHG4 gene. The structural features of theLAT IGHG3 allele, which are the lack of one hinge exon and its conversion by theIGHG4 gene, demonstrate that both crossing-over and gene conversion events occur in the evolution of the humanIGHG genes. The nucleotide sequence data reported in this paper have been submitted to the GenBank nucleotide sequence database and have been assigned the accession number X16110.     

Allelic variation adjacent to the human insulin and apolipoprotein C-II genes in different ethnic groups

Summary We have used DNA probes for the human insulin gene and apolipoprotein C-II (apo C-II) gene to determine the extent of allelic variation in different ethnic groups. The distribution of an apo C-II DNA polymorphism revealed by the restriction endonuclease Taq I showed no significant variation amongst racial groups; in contrast, an insulin gene-related DNA polymorphism showed marked variability. In Japanese, Chinese, and Asian Indian groups there was an increased frequency of homozygosity for the class 1 allele compared to Caucasian groups (P<0.001, P<0.01, and P<0.05, respectively). In Caucasian, Japanese, Chinese, and Asian Indian groups no class 2 allele was observed; but in the Negroid populations (African and West Indian) the class 2 allele frequencies were 0.23 and 0.25 respectively. Possible reasons for this variation in allele distribution are considered in relation to disease associations.     

HLA-B alleles of the Cayapa of Ecuador: new B39 and B15 alleles

Recent data suggest that HLA-B locus alleles can evolve quickly in native South American populations. To investigate further this phenomenon of new HLA-B variants among Amerindians, we studied samples from another South American tribe, the Cayapa from Ecuador. We selected individuals for HLA-B molecular typing based upon their HLA class II typing results. Three new variants of HLA-B39 and one new variant of HLA-B15 were found in the Cayapa: HLA-B ^*3905, HLA-B^*3906, HLA-B^*3907, and HLA-B ^*1522. A total of thirteen new HLA-B alleles have now been found in the four South American tribes studied. Each of these four tribes studied, including the Cayapa, had novel alleles that were not found in any of the other tribes, suggesting that many of these new HLA-B alleles may have evolved since the Paleo-Indians originally populated South America. Each of these 13 new alleles contained predicted amino acid replacements that were located in the peptide binding site. These amino acid replacements may affect the sequence motif of the bound peptides, suggesting that these new alleles have been maintained by selection. New allelic variants have been found for all common HLA-B locus antigenic groups present in South American tribes with the exception of B48. In spite of its high frequency in South American tribes, no evidence for variants of B48 has been found in all the Amerindians studied, suggesting that B48 may have unique characteristics among the B locus alleles.The nucleotide sequence data reported in this paper have been submitted to the GenBank nucleotide sequence database and have been assigned the accession numbers U14756 (HLA-B ^*1522), U15683 (HLA-B ^*3905), U15639 (HLA-B ^*3906), and U15640 (HLA-B ^*3907)The names listed for these sequences were officially assigned by the WHO nomenclature Committee in September 1994, B ^*3905, and November 1994, B ^*1522, B^*3906, and B ^*3907. This follows the agreed policy that, subject to the conditions stated in the most recent Nomenclature Report (Bodmer et al. 1994), names will be assigned to the new sequences as they are identified. Lists of such new names will be published in the following WHO Nomenclature Report.     

Distribution of hereditary blood groups among Indians in South America. V. In northern Brazil

This paper reports the results of tests made for hereditary antigens in blood samples procured from Indians in northern Brazil. Specimens were procured from 423 putatively full-blood persons of the following tribes: in the province of Roraima from 261 Macuxi, 48 Uaica, 27 Xirixano, 10 Uapixana, 9 Cacarapai and 9 Paramiteri; in Pará from 21 Assurini; and in Amapá from 38 Galibi. Erythrocyte samples were tested for factors in the A-B-O, M-N-S-s, P, Rh-Hr, Lutheran, Kell-Cellano, Lewis, Duffy, Kidd and Diego systems. Serum samples were tested for haptoglobins and transferrins. Hemolysates, prepared from whole blood, were tested for hemoglobin types. The results are presented on appropriate tables as number and per cent of phenotypes for the various blood group anigens and their calculated gene frequencies. Locations from which blood samples were procured are listed in the tables and shown on a map (fig. 1). All the 423 samples except one Macuxi belonged to group O. The Uaica tribe had a low frequency for M (0.534). All others showed the high frequency usually observed in Amerinds. The s allele was high in all except the Galibi in which the frequency was (0.500). Frequencies for P² was higher than for P¹ in all except the Assurini and Galibi, theirs was high for P¹ (1.00) and low for P² (0.00). The frequencies for R¹ (CDe) and R² (cDE) were high and all others in the Rh-Hr system were low or absent. All specimens were positive for Cellano (k) and negative for Kell (K). There was a complete absence of Lewis (Le₁), excepting in the Uaica and Xirixano in which populations Fy^a allele frequencies were higher than 0.500. The distribution of the Jk (a+) phenotype and corresponding ellele frequencies varied widely in Brazilian Indians as did those for Diego (a+). The haptoglobin Hp¹ allele frequencies were in essential agreement with those reported elsewhere for Indians in South America, and all transferrins determined were classified as Tf C. All samples tested for homoglobin types contained homoglobin (A) as a major component, but five members of the Galibi tribe possessed hemoglobin (S) as well.     

Gm and Km(Inv) frequencies in two Roumanian populations

Summary Serum samples from 170 unrelated individuals from the Suceava District of Roumania and from 199 unrelated individuals from Bucharest, Roumania were tested for Gm(1, 2, 3, 5, 6, 13, 14, 17, 21) and Km(1)[Inv(1)]. Selected samples were also tested for Gm(15) and Gm(16).The frequencies of the three common Caucasoid haplotypes, Gm ^{3, 5, 13, 14}, Gm ^{1, 17, 21}, and Gm ^{1, 2, 17, 21} in these two populations were found to be similar to those in neighboring Slavic states and Hungary. Racial admixture was evidenced by the presence of the Gm ^{1, 13, 15, 16, 17} and Gm ^{1, 3, 5, 13, 14} haplotypes, which are primarily Mongoloid, and the Gm ^{1, 5, 13, 14, 17} haplotype which is primarily Negroid.Comparisons of these data with those from earlier studies of populations from Central Europe indicate that the frequency of the Gm ^{3, 5, 13, 14} haplotype within this region is high and essentially uniform. Published data for several blood group systems also indicate essentially uniform distributions of frequencies in this region. It is suggested that this region may be the center of a clin that radiates from it.Post-Doctoral Fellow supported by NIH Training Grant Gm07004.     

Gm and Inv [Km] allotypes among Libyan and Ashkenazi Jews,and Armenians living in Israel

Summary Serum samples from Armenians, and from Libyan and Ashkenazi Jews living in Israel were tested for Gm (1, 2, 3, 5, 6, 10, 11, 13, 14, 17, 21, 24, 26) and for Inv(1) [Km(1)].The Gm data indicate that all three populations have Negroid and Mongoloid admixture. The minimum amount of admixture varies from 3.1% (Armenians) to 5.5% (Libyan Jews). This admixture had not been detected by the study of other polymorphisms, thus once again underlining the sensitivity of the Gm system. The haplotype frequencies among the Libyan Jews are markedly different from those among the Ashkenazi Jews. Surprisingly (coincidentally?) the haplotype frequencies among the Ashkenazi Jews and the Armenians are similar.The Libyan Jews have a significantly higher frequency of Inv ¹ than do the Ashkenazi Jews and among the latter, Inv ¹ is at least twice as frequent among Polish Jews as it is among Russian Jews.     

Population genetic studies of the Aka Pygmies (Central Africa)

Summary Blood samples collected in a single Pygmy tribe, the Aka, living in Bokoka district (Central African Empire) were investigated with respect to the phenotype and gene frequencies of the following 12 enzyme systems: acid phosphatase, adenosine deaminase, adenylate kinase, carbonic anhydrase, esterase D, glucose-6-phosphate dehydrogenase, malate dehydrogenase, phosphoglucomutase 1, phosphoglucomutase 2, phosphogluconate dehydrogenase, superoxide dismutase and serum cholinesterase variants (locus E₁ and E₂). The data obtained in the study of genetic polymorphisms of this isolated and inbred population show a specific pattern with the following characteristics: the very low frequency of PGD^B and p^a alleles; the existence of two rare PGM variants at the PGM₂ locus, typical PGM ₂ ^6Pyg (4.2%) and PGM ₂ ⁹ (0.2%); the high frequency of the p^r allele (10.8%) and CA _II ² (8.22%) and ESD² genes (18.4%). Furthermore, at the G6PD locus four distinct alleles have been found: the negroid GDA-(4%) and GdA+(16%), the common GdB+(79.2%)-,and the rare Gd+^{Ibadan Austin} (0.7%). Cholinesterase typings disclosed the presence of the uncommon E ₁ ^f and E ₁ ^s genes distributed within a single breeding unit. The results are compared with other data previously reported on South African Khoisan and some Negroid populations; the particular genetic background of Pygmies is discussed.Otherwise known as Bi Aka     

Extensive polymorphism of the FUT2 gene in an African (Xhosa) population of South Africa

The human secretor type α(1,2)fucosyltrans-ferase gene (FUT2) polymorphism was investigated in Xhosa and Caucasian populations of South Africa by polymerase chain reaction–restriction fragment length polymorphism and DNA sequencing. Six new base substitutions were found in the coding region of FUT2. A single base (C) deletion at nucleotide 778, which led to a frame shift and produced a stop codon at codon 275, was responsible for the enzyme inactivation. Three nonsynonymous base substitutions, A40G (Ile¹⁴Val), C379T (Arg¹²⁷Cys), and G481A (Asp¹⁶¹Asn), and two synonymous base substitutions, A375G (Glu¹²⁵) and C480T (His¹⁶⁰), were also identified in functional alleles. As a result, seven new alleles, Se ⁴⁰ , Se ⁴⁸¹ , Se ^40,481 , Se ^357,480 , Se ^357,379,480 , Se ³⁷⁵ , and se ^357,480,778 were identified. Population studies revealed that an allele containing a nonsense mutation G428A (Trp¹⁴³stop) (se ⁴²⁸ ) was the common null allele in both Xhosa and Caucasian populations, whereas an allele containing a missense A385T (Ile¹²⁹Phe) mutation (se ^357,385 ), which is the common null allele in Orientals, was found to be absent from both populations. The heterozygosity rates of FUT2 genotypes were as high as 0.75 in the Xhosa population and 0.65 in the Caucasian population. Therefore, the extensive polymorphism and race specificity of the FUT2 gene make it suitable for application as a new tool in genetic studies of modern human evolutionary history. Received: 23 March 1998 / Accepted: 9 May 1998     

Molecular analysis of the gene for the human vitamin-D-binding protein (group-specific component): allelic differences of the common genetic GC types

Summary DNA sequence analysis of the polymerase chain reaction products, including the coding region for amino acids 416 and 420, of the vitamin-D-binding protein (DBP, group-specific component, GC) shows allelespecific differences. The GC2 and GC1F phenotypes have an aspartic acid residue at amino acid position 416, whereas the GC1S phenotype has a glutamic acid at this position. In the GC2 phenotype, amino acid 420 is a lysine residue, and in the both common GC1 phenotypes, it is a threonine residue. The nucleotide exchanges involve a HaeIII (position 416) and a StyI (position 420) restriction site: the HaeIII restriction site is specific for the GC^*1S allele and the StyI restriction site is specific for the GC^*2 allele. We have tested 140 individual genomic DNA samples for the HaeIII site and 148 samples for the StyI site by restriction fragment length polymorphism (RFLP) analysis with a DBP-specific direct genomic DNA probe, and have compared these findings with the GC phenotype classification, by isoelectric focusing (IEF) of the corresponding plasma. The results of the HaeIII RFLP analysis and the IEF typing were in complete agreement. By using our DNA probe, we could disclose, in addition to the StyI site at amino acid position 420, two further StyI site downstream: one was specific for the GC^*1S allele and another for the GC^*1F allele. In 147 samples, there was agreement between the IEF GC typing and the analysis of the StyI restriction sites. In a single case, the observed result of the StyI-digest differed from the result expected after IEF classification: homozygous GC 1F-1F by IEF and heterozygous by StyI RFLP analysis. We discuss this finding as a recombination event or a possible silent allele in IEF typing. The GC polymorphism revealed by Southern blot analysis of StyI-digests provides an informative DNA marker system for chromosome 4q11–q13.