['In 1992, a family with hereditary macrothrombocytopenia and progressive sensorineural hearing impairment without renal dysfunction was described. Recently, mutations in MYH9, a nonmuscle myosin heavy chain, have been found in several forms of hereditary macrothrombocytopenia.', 'The hereditary macrothrombocytopenia and hearing loss in the previously reported family is due to a mutation in MYH9 gene.', 'Genomic DNA was extracted from the affected proband. Mutation screening of all MYH9 coding exons was carried out using denaturing high-performance liquid chromatography. Abnormal results were followed by direct sequencing of the exon and comparison of the sequence with the normal MYH9 sequence.', 'The results of denaturing high-performance liquid chromatography suggested a potential sequence alteration in exon 30 of MYH9. Direct sequence analysis of this exon in the affected individual identified a G to A single base pair transition at nucleotide 4270 altering codon 1424. This mutations leads to an amino acid change from aspartate (D) to asparagine (N) in the highly conserved coiled-coil domain.'] Is macrothrombocytopenia and progressive deafness due to a mutation in MYH9?