Brief Reports

VOX S a g . 27: 261-264 (1974)

Scismna Blood Group System'

MARION LEWIS, HIROKO KAITA and B. CHOWN

Rh Laboratory and Department of Paediatrics, University of Manitoba, Winnipeg

Abstract. The authors suggest that the blood group antigens currently known as Sm and Bua be renamed Sc 1 and Sc 2 respectively, that the blood group system which they comprise be called Scianna and the locus controlling their production Sc. Linkage analysis by the lod score method rules out close linkage between Sc and ABO, Do, Fy, Jk, MN and P.

The blood group antigens Sm and Bus have been shown to bear an antithetical relationship to each other [7] and to be inherited independently of all established blood group systems [2, 3, 61 save Diego and Colton. This communication presents our suggested terminology for the blood group system which they comprise, phenotype and gene frequencies based on testing 1,OOO unrelated Caucasian adults with anti-Sm and anti-Bus, and a linkage analysis of the Scianna locus and other markers.

Nomenclature

The proposita of the family in which anti-Sm was first described [9], Mrs. Scianna, has given permission for the use of her name. We propose that the system be called Scianna, the locus Sc, and the defined alleles Scl and Sca:

Gene Antigen Antibody

SC' Sc 1 (formerly Sm) anti-Sc 1 (formerly anti-Sm) SCa Sc 2 (formerly Bua) anti-Sc 2 (formerly anti-Bua)

Work supported by MRC (Canada) grant MT 3391.

Received: January 14, 1974; accepted: January 15, 1974.

262 LEWISIkhTAIcHOWN

Table I. Linkage analysis for Sc and other loci

Segregation informa- tion: paternal maternal Total'

Assumed recombina- tion fraction: 0.10 0.30 0.10 0.30 0.10 0.30

Loci: Sc and ABO

AcPh Do FY GC HP Jk Kell Le Lu MN P Rh 6PGD

- 5.214 - 0.229 - 3.870 - 0.393

- 0.444 - 3.347

0.430 -0.199 - 1.058 - 0.323 - 1.823

0.921 0.216

-0.586 - 0.01 1 - 0.650

0.281

- 0.076 -0.488

0.129 - 0.003 - 0.008

0.524 -0.316

0.815 0.065

-8.137 -1.331 - 0.059 -2.679

0.271 0.223

- 4.649 - 1.345

0.003

- 2.981 -3.696 - 5.572

0.322

- 1.653 -0.227

0.030 - 0.461

0.223 0.155

-0.714 -0.174

0.090

- 0.632 - 0.485 -0.910

0.363

- 13.704 - 1.560 - 4.208 - 5.151

0.277 - 0.186 - 8.851 - 0.915 - 0.138 - 1.058 - 6.392 - 5.606 - 3.678

0.538

- 2.064 - 0.238 -0.635 -0.376

0.223 0.105

-1.243 -0.045

0.102 - 0.008 -0.501 -0.798

0.092 0.428

Includes intercross.

Frequencies

In a series of 1,OOO unrelated Caucasian adults tested with anti-Sc 1 and anti-Sc 2, we found 17 Sc:l, 2 and 983 Sc:l, -2. The gene frequency for Sca (0.0085) is somewhat higher than but not significantly different from that in earlier studies where only anti& 2 was used [6, lo]. Sc 2 has not been found in 212 Negroes [6], 100 Manitoba Indians [I] and 75 Eskimo [4]. The only population in which it has been found to have an appreciably high frequency is an inbred Mennonite community [7].

Inheritance

The alleles Scl and Sc2 are co-dominant. The only exceptional phenotype observed, Sc: - 1, -2, has recently been described by MCCREARY et al. [8];

Scianna Blood Group System 263

family study did not elucidate the genotype or the genetic mechanism involved. This phenotype is evidently rare : at least 1,600 random people have been tested with anti-Sc 1 (this study and that of SCHMIDT et al. [9]) and all were Sc: 1, while all Sc: - 1 people known to the authors have been Sc: 2. Finally, none of 162 children born to 41 couples of the mating type Sc: 1,2 x Sc: 1, -2 has been Sc: - 1, 2.

Linkage analysis

Lod scores obtained by the Mark 111 version of Prof. JOHN H. EDWARDS Linkage Programme are set out in table I. They are based on all of the data we have on informative families. While they rule out any close linkage between Sc and ABO, Do, Fy, Jk, MN and P, it is evident from our limited list of loci that families in which Sc is segregating should be tested for as many genetic markers as possible.

Acknowledgments

We are indebted to Dr. H. SEYFRIED and Dr. J. J. GRIFFITTS for the anti8c 2 (Soch) and anti-Sc 1 (Sci) reagents which we continue to use, to Dr. ELOISE R. G m u m for red cell enzyme results and to Dr. A. G. STEINBERG for the serum typings. We are also most grateful to Prof. JOHN H. EDWARDS for making his Linkage Programme available to us. Finally, we are particularly grateful to Mr. GILBERT B. COTE for his adaptation of the Programme to our needs and the University of Manitoba Computer, and for his patient instruction.

References

1 ALLEGRO, L. ; KAITA, H. ; LEWIS, M.; ANDERSON, J., and GIBLETT, E. R.: Some genetic

2 ANDERSON, C.; HUNTER, J.; ZIPURSKY, A.; LEWIS, M., and CHOWN, B.: An antibody

3 GILES, C. M.; BEVAN, B., and HUGHES, R. M.: A family showing independent segrega-

4 KAITA, H. : Unpublished observations. 5 LEWIS, M.; CHOWN, B.; SCHMIDT, P. R., and GRJFFITTS, J. J.: A possible relationship

between the blood group antigens Sm and Bun. Amer. J. hum. Genet. 16: 254-255 (1964).

6 LEWIS, M.; CHOW, B.; KAITA, H., and PHILIPPS, S.: Further observations on the blood group antigen BuS. Amer. J. hum. Genet. 16: 256-260 (1964).

markers in a Manitoba Indian population (in preparation).

defining a new blood group antigen Bus. Transfusion, Philad. 3: 30-33 (1963).

tion of Bus and Ytb. Vox Sang. 18: 265-266 (1970).

7 LEWIS, M.; -OWN, B., and KAITA, H.: On the blood group antigens Bua and Sm. Transfusion, Philad. 7: 92-94 (1967).

8 MCCREARY, J.; VOGLER, A. L.; SAEO, B.; ECKSTEIN, E. G., and SMITH, T. R.: Another Minus-Minus phenotype: Bu(a -) Sm - , two examples in one family. Abstracts AABB, Transfusion, Philad. 13: 350 (1973).

9 SCHMIDT, R. P.; GRIFFRTS, J. J., and NORTHMAN, F. F.: A new antibody, antidm, reacting with a high incidence antigen. Transfusion, Philad. 2: 338-340 (1962).

10 SEYFRIED. H.; FRANKOWSKA, K., and GEES, C. M.: Further examples of anti-Bua found in immunized donors. Vox Sang. ZZ: 512-516 (1966).

Request reprints from: MAWON LEWIS, Rh Laboratory and Department of Paediatrics, University of Manitoba, Winnipeg, Man. (Canada)