Genes for thrombopoietin and c-mpl are not responsible for familial thrombocythaemia: a case study

The underlying molecular basis for familial thrombocythaemia (FT), an extremely rare form of primary thrombocythaemia which occurs in an autosomal dominant manner, is currently unknown, We have investigated a family with FT and clarified whether we could detect alteration(s) in the genes coding for c-mpl and its ligand, thrombopoietin (TPO). There was no difference in platelet c-mpl mRNA expression levels between the affected and nonaffected individuals in the family. Nucleotide sequence analysis of the c-mpl cDNA for the proband revealed no abnormality. We identified an intragenic tetranucleotide short tandem repeat system in the TPO gene and found non-linkage between the TPO locus and the FT phenotype. We conclude that genes for c-mpl and TPO are not responsible for thrombocythaemia in our FT family.