Exclusion of 5 functional candidate genes for distal hereditary motor neuropathy type II (distal HMN II) linked to 12q24.3.

Distal hereditary motor neuropathies (distal HMNs) are characterised by degeneration of anterior horn cells of the spinal cord resulting in muscle weakness and atrophy. Distal HMN type II is genetically linked to chromosome 12q24.3 and located within a 13 cM region flanked by markers D12S86 and D12S340. We previously excluded the human phospholipase A2 group 1B gene (PLA2G1B) as the disease causing gene. Here, we report the mutation analysis of five other candidate genes localised within the distal HMN II region: the cytoskeletal proteins paxillin (PXN) and restin (RSN); the acidic ribosomal phosphoprotein, large P0 subunit (RPLP0); a nucleoside diphosphate kinase (NME2B); and the beta 3 subunit of the voltage-gated calcium channel (CACNB3). DNA sequencing of the coding regions was performed but no disease causing mutations could be identified, hence excluding these five genes for distal HMN type II.