MUTATION 3.7 kb (type III) deletion involving the 3' part of the alpha2 gene and 5' part of the alpha1 gene
 
AMINO ACID REPLACEMENT None
TYPE OF ALPHA-THAL alpha-Thal-2 [-alpha/]
MECHANISM See Fig. 22
IDENTIFICATION Gene mapping; PCR methodology with probes 5' and 3' to the deletion
HEMATOLOGY IN HETEROZYGOTE(S) AND HOMOZYGOTE(S) See table below (from Ref. 3)
Age
group 		n Mean
age 		Hb
g/dl 		RBC
1012/l 		MCV
fl 		MCH
pg
-alpha/-alpha
3-4
4-6
6-8
8-10
10-13
13-15
15-18		19
23
34
30
35
17
16		3.5
5.0
6.8
8.8
10.8
13.3
15.8		10.6
11.2
11.5
11.6
11.9
12.0
12.2		5.28
4.96
5.23
5.16
5.16
5.51
5.24		68.7
70.0
69.9
72.0
73.6
71.6
75.5		20.6
22.9
22.3
22.5
23.2
21.8
23.4
-alpha/alphaalpha
3-4
4-6
6-8
8-10
10-13
13-15
15-18		45
72
83
105
114
46
41		3.4
4.9
6.9
8.9
11.0
13.4
16.0		11.1
11.3
11.6
12.0
12.3
12.9
12.6		4.84
4.63
4.66
4.82
4.89
4.95
4.74		73.1
75.3
75.8
76.9
78.5
80.5
83.8		23.3
24.8
25.1
25.0
25.2
26.1
26.8
alphaalpha/alphaalpha
3-4
4-6
6-8
8-10
10-13
13-15
15-18		101
140
134
144
185
52
42		3.4
4.8
7.0
8.8
11.0
13.4
15.9		11.7
11.6
12.3
12.4
12.5
12.8
12.7		4.59
4.47
4.52
4.62
4.57
4.72
4.44		78.5
79.5
80.1
80.8
84.3
83.9
88.6		25.8
26.2
27.4
27.1
27.4
27.3
28.8
OCCURRENCE Mostly in Melanesian and Polynesian populations
HAPLOTYPE Not determined
OTHER INFORMATION The crossover is within a 46 bp region of homology at the 3' end of the alpha genes
       
REFERENCES
1. Higgs, D.R., Hill, A.V.S., Bowden, D.K., Weatherall, D.J., and Clegg, J.B.: Nucleic Acids Res., 12: 6965, 1984.
2. Hill, A.V.S., Bowden, D.K., Trent, R.J., Higgs, D.R., Oppenheimer, S.J., Thein, S.L., Mickleson, K.N.P., Weatherall, D.J., and Clegg, J.B.: Am. J. Hum. Genet., 37:571, 1985.
3. Williams, T.N., Maitland, K., Ganczakowski, M., Peto, T.E.A., Clegg, J.B., Weatherall, D.J., and Bowden, D.K.: Br. J. Haematol., 95:266, 1996.

This material is from the book A Syllabus of Thalassemia Mutations (1997) by Titus H.J. Huisman, Marianne F.H. Carver, and Erol Baysal, published by The Sickle Cell Anemia Foundation in Augusta, GA, USA. Copyright © 1997 by Titus H.J. Huisman. All rights reserved. Neither this work nor any part may be reproduced or transmitted in any form or by any means, electronic or mechanical, microfilming and recording, or by any information storage and retrieval systems, without permission in writing from the Author.