Spectrin Tunis (alpha I/78): a new alpha I variant that causes asymptomatic
hereditary elliptocytosis in the heterozygous state
L Morle, N Alloisio, MT Ducluzeau, B Pothier, R Blibech, R Kastally and J Delaunay
Genetique Moleculaire de la Membrane Erythrocytaire, Faculte de Medecine
Grange Blanche, Lyon, France.
Spectrin Tunis (alpha 1/78) was found in the heterozygous state in a young
white North-African man and his mother. Both of them presented with mild
elliptocytosis. Using one-dimensional electrophoresis, a sharp 78 kd
fragment was present with a reciprocal decrease of the alpha I 80 kd
domain. Kinetic analysis unambiguously confirmed that the 78 kd fragment
developed at the expense of the alpha I 80 domain. The alpha I 74 kd
peptide was not flanked with a peptide lacking a 2 kd fragment. From this
fact, it could be inferred that the site for additional proteolysis is
located upstream from arginyl residue 39 and, more precisely, should lie 10
to 20 amino-acid residues (-2 kd) from the alpha-chain N-terminus. The
percentage of spectrin dimers in 4 degrees C extracts was high (over 40%),
contrasting with the absence of clinical symptoms related to
elliptocytosis. This is the first mutation responsible for elliptocytosis
found in Tunisia.
Volume 71,
Issue 2,
pp. 508-511,
02/01/1988
Copyright © 1988 by The American Society of Hematology
