According to Cardon et al. 2003, a haplotype block is
A discrete chromosome region of high linkage disequilibrium and low haplotype diversity. It is expected that all pairs of polymorphisms within a block will be in strong linkage disequilibrium, whereas other pairs will show much weaker association. Blocks are hypothesized to be regions of low recombination flanked by recombination hotspots.
It seems obvious that the parts of the genome that compose genes will have a somewhat similar behavior.
So what are the differences between haplotype blocks and genes? Are genes a kind of haplotype block?
Cardon, L. R., and G. R. Abecasis. 2003. Using haplotype blocks to map human complex trait loci. Trends in Genetics 19:135–140.