Abnormalities of the gene occur rarely by chromosomal translocation into the T-cell receptor (TCR) delta locus and commonly by a site-specific 95-kb deletion, SIL-SCL (tald).     ///    "Analysis of the SIL-SCL deletion by Southern blotting and polymerase chain reaction (PCR) in a series of 52 immature T-cell malignancies showed a type A deletion in 21% of cases, but no type B deletions. "    ///    These data demonstrate an association between SCL disruption and TCR alpha beta lineage differentiation and suggest that the SIL-SCL deletion occurs at the same stage of ontogeny as TCR delta deletion..     ///    "Six of eight SIL-SCL type A cases had undergone bilateral delta deletion, whereas only one of 31 cases with an apparently normal SCL gene had done so. "