Ankyrin-linked hereditary spherocytosis in an African-American kindred.
Mutations of ankyrin-1 are the most frequent cause of the inherited hemolytic anemia, hereditary spherocytosis (HS), in people of European ancestry. Ankyrin-1, which provides the primary linkage between the erythrocyte membrane skeleton and the plasma membrane, has numerous isoforms generated by alternative splicing, alternate polyadenylation, use of tissue-specific promoters, and alternate NH(2) or COOH-termini. Mutation detection in erythrocyte membrane protein genes, including ankyrin, has been a challenge, primarily due to the large size of these genes, and the apparent frequent occurrence of HS-associated null alleles. Using denaturing high-performance liquid chromatography (DHPLC), we screened the ankyrin gene of the proband of a large, three generation African-American kindred with ankyrin-deficient HS. DHPLC yielded an abnormal chromatogram for exon 1. Examination of the corresponding exon 1 sequence in genomic DNA from the proband revealed heterozygosity for a mutation of the initiator methionine (ATG to ATA Met 1 Ile). Coupled in vitrotranscription/translation studies with rabbit reticulocyte lysates demonstrated that the wild-type ankyrin erythroid cDNA initiates only from the known initiator methionine, indicating that the use of alternate initiator methionine is not a mechanism of isoform diversity in erythroid cells. The mutant ankyrin allele, unlike some initiator methionine mutations that utilize downstream codons for translation initiation, was associated with a null allele. This is the first report describing ankyrin-linked HS in an African-American kindred.
Sangerman
Jose
J
Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut 06520-8064, USA.
Maksimova
Yelena
Y
Edelman
E Jennifer
EJ
Morrow
Jon S
JS
Forget
Bernard G
BG
Gallagher
Patrick G
PG
D001741:Black or African American / Q000235:genetics*; D000483:Alleles; D017487:Ankyrins / Q000172:deficiency* / Q000235:genetics; D001483:Base Sequence; D016022:Case-Control Studies; D002851:Chromatography, High Pressure Liquid; D003062:Codon; D004252:DNA Mutational Analysis; D005091:Exons; D005190:Family; D005260:Female; D005787:Gene Frequency; D005820:Genetic Testing; D006579:Heterozygote; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D009154:Mutation; D010375:Pedigree; D035781:Siblings; D013103:Spherocytosis, Hereditary / Q000235:genetics*
D017487:Ankyrins; D003062:Codon