HAX1 transcript variants and summary of known mutations in patients with CN. (A) The intron-exon structure with the coding region (▒) for both isoforms of the HAX1 gene is shown. ● indicates the position of the mutations; each symbol represents a single patient (mutations were homozygous in all patients). Novel mutations are printed in bold letters. (B) Expression of transcript variants in peripheral blood cells (PB) and brain tissue. cDNAs from peripheral blood mononuclear cells (lanes 2 and 4) and from human brain (lane 3) have been amplified as described in “Methods.” A distinct band for transcript variant 2 could be detected only after secondary PCR (lane 4). The identity of transcript variants 1 and 2 has been confirmed by sequencing. The band migrating between the 2 variants consisted of heteroduplices of the 2 variants as confirmed by sequencing. (C) Expression of HAX1 isoforms in the HL-60 cell line. Western blot analysis was performed with total-cell lysate.