Key result
Donor splice-site G+1 mutation yields minimal correctly spliced transcript, causing total enzyme deficiency.
Why the study?
The impact of a mutation at the donor splice site G+1 position on splicing and transcript levels in lipoprotein lipase deficiency was unclear.
Case Report (n=1)
Rare splice-site mutations may cause complete LPL deficiency via minimal residual transcript; extends mechanistic understanding but remains hypothesis-generating.
The consequence on the splice mechanism of a mutation occurring at the donor splice site of intron 1 has been studied. We demonstrate that, in spite of the change at G+1 position, this site is still utilized and can produce correctly spliced transcript. Nevertheless the mRNA is detectable only after an 'in vitro' amplification. A procedure has been developed to reveal and quantify the minute amount present in the patient. The very low mRNA level results in a total lack of enzyme, the cause of the disease. The procedure can be useful in cases of rare transcripts and when the source is limited. Furthermore we analyse the interaction between the splice consensus sequence and the small nuclear RNA, that is the necessary intermediate of the splicing mechanism. We speculate on the reasons why cryptic sites are not utilized and only the authentic site can be used, although significantly destabilized by the mutation.
No takes yet. Share an insight, caveat, or question.
Pepe et al. (1993) conducted a case report in Lipoprotein lipase deficiency (n=1). Mutation at G+1 donor splice site of intron 1 was evaluated on Splice mechanism and transcript quantity. Despite a G+1 mutation at the donor splice site, correctly spliced transcript is still produced but in very low amounts, leading to total enzyme deficiency.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: