Mental　retardation　(MR)　is　a　common　form　of　cognitive　impairment　among　children.　The　underlying　causes　of　mental　retardation　are　extremely　heterogeneous　and　include　significant　genetic　factors.　Long　chain　fatty　acid-CoA　ligase　4　is　the　first　gene　shown　to　be　involved　in　mental　retardation　and　fatty-acid　metabolism.　FACL4　gene　mutations　in　three　Italian　MR　pedigrees　have　been　reported　as　causing　non-specific　mental　retardation.　To　investigate　the　possible　genetic　contribution　of　the　FACL4　gene　to　non-specific　mental　retardation　children　of　the　Qin-Ba　mountain　region　in　China　we　performed　an　association　study　of　556　subjects　(118　NSMR,　116　borderline　NSMR,　and　322　controls)　from　the　Han　children　of　northwestern　China　using　five　common　SNPs　(rs5943427,　rs12856122,　rs5943418,　rs7886473,　and　rs10126612)　in　the　gene.　No　significant　differences　of　genotypes　and　alleles　frequencies　from　each　single　SNP　between　NSMR　and　controls　were　observed.　Pairwise　linkage　disequilibrium　analysis　showed　that　four　SNPs　rs5943427,　rs12856122,　rs5943418,　and　rs7886473　were　in　strong　linkage　disequilibrium;　therefore,　a　haplotype　analysis　was　performed.　However,　there　were　no　any　significant　differences　in　haplotype　distributions　between　cases　and　controls.　In　conclusion,　we　have　found　no　evidence　for　the　FACL4　gene　conferring　susceptibility　on　non-specific　mental　retardation　children　of　the　Qin-Ba　mountain　region　in　China.　(C)　2008　Elsevier　Ireland　Ltd.　All　rights　reserved.