Defining the breakpoints of proximal chromosome 14q rearrangements in nine patients using flow-sorted chromosomes

The breakpoints of deletions and translocations in the proximal chromosome 14q region were defined in nine patients, four of whom have not been reported previously. The aberrant chromosomes were isolated by flow cytometry and used to map the chromosome 14 deletion or translocation breakpoints. The parental origins of deletions were ascertained as paternal in five cases and maternal in one. With the draft genomic sequence for human chromosome 14 available, gene searches were performed on selected intervals of the 14q11.2-q21 region to identify candidate genes for the observed phenotype in some of those affected. Gain of function of the gene PAX9 on chromosome 14 is a possible candidate for a t(14;18) patient affected with mesomelic bone dysplasia. Furthermore, a compilation of other human chromosome 14q proximal deletion and translocation cases was obtained from a search on cytogenetic databases. These findings suggest a locus for myelofibrosis at chromosome 14q13. This study contributes to useful information for identifying disease genes in this region.