t(1;7)(p32;q34)

t(1;14)(p32;q11)

Identity

Note	the two chromosome anomalies are variants of each other, and they share identical features


	t(1;14)(p32;q11) ) G-banding (left)- Courtesy Diane H. Norback, Eric B. Johnson, and Sara Morrison-Delap, UW Cytogenetic Services and R-banding (right) - Courtesy Isabelle Radford-Weiss

Clinics and Pathology

Disease	T- cell ALL
Epidemiology	rare findings; t(1;14) is found in approximately 3% of T-ALL; t(1;7) is rarer (status 3: < 5 cases); however, TAL1 rearrangements, all together (being mostly submicroscopic deletions without visible 1p32 involvement), occurs in 15-25% of T-ALL; male predominance (as is classical in T-cell ALL)
Clinics	organomegaly; high WBC (median 200X 10⁹/l)

Cytogenetics

Additional anomalies

t(1;14) is found solely in about half cases, and accompanied by del(6q) in nearly half cases as well

Genes involved and Proteins

Gene Name	TAL1
Location	1p32
Dna / Rna	complex alternate splicing
Protein	contains a basic Helix-Loop-Helix (DNA binding) domain; forms heterodimers; transcription factor; role in haematopoietic cell differentiation

Gene Name	TRA/D
Location	14q11 in the case of a t(1;14)

Gene Name	TRB
Location	7q35 in the case of a t(1;7)

Result of the chromosomal anomaly

Fusion Protein



Description	in most cases (breakpoints between exons 2B and 3 of TAL1), 3' TAL1 joins variable and diversity segments of TCR on der(14); in the few cases where the breakpoint is within exon 6 of TAL1 or 3' from it, constant segments of TCR join TAL1 on der(1)