Table 1

The known BRCA1 splice variants in humans, indicating the exon(part)s missing, the tissues where a variant is most abundant, and also whether the encoded protein keeps the original open reading frame (ORF)

Name of the variantKeeps the ORF?TissuesRefs
When the gene was cloned, an inserted Alu element was mistakenly identified as exon 4,1 but this is omitted from the table.
5q, the last 22 nt are missing form exon 5; 11q, the last 3309 nt are missing from exon 11 (∼3% of the exon is kept only).
*Because many variants are named differently in the literature, the numbers in parenthesis correspond to the reference sequences in LocusLink, where available. †It has only been described in the Δ(11q) variant.
nt, nucleotides.
Full length BRCA1YesBreast, ovary, testis, thymus, various other 1
With exon 1a (NM_007294*)YesBreast, ovary, testis, thymus57, 58
With exon 1b (NM_007295*)YesPlacenta 57
Δ(2–10) (NM_007297*)YesBreast, lymphocytes 49
Δ(5)YesBreast, ovary, lymphocytes1, 48, 59, 60
Δ(5q,6)YesBreast, lymphocytes 60
Δ(9,10) (NM_007302*)YesBreast, ovary, lymphocytes1, 12, 46, 48, 61
Δ(9,10,11q) (NM_007305*)YesBreast, ovary, lymphocytes12, 46, 49, 61
Δ(9,10,11) (NM_007298*)YesBreast, lymphocytes1, 49
Δ(11q) (NM_007304*)YesBreast, ovary, lymphocytes12, 46, 48, 49, 61
Δ(11) (NM_007303*)YesOvary, thyroid47, 62
Δ(14–17) (NM_007299*)YesBreast, lymphocytes 49
Δ(14–18) (NM_007300*)YesBreast, lymphocytes 49
Δ(3)NoBreast, lymphocytes 60
Δ(3,5q)NoLymphocytes 60
Δ(5q)NoBreast, ovary, lymphocytes59, 60
Δ(6,7)NoLymphocytes 60
Δ(9)NoLymphocytes 60
Δ(15–17) (NM_007301*)NoBreast, lymphocytes 49
Usage of leaky splice sites
    +3 nt for 5′ of exon 8YesBreast 1
    +3 nt for 5′ of exon 14YesBreast 1
    −3 nt from 5′ of exon 8YesBreast, lymphocytes 60
    −3 nt from 5′ of exon 12†YesBreast 47
    −6 nt from 3′ of exon 1a (NM_007296*)YesKidney, lung, other 58