Association of a null mutation in the CNTF gene with early onset of multiple sclerosis

Background: Immune-mediated demyelination and axonal damage lead to early functional impairment in multiple sclerosis (MS). Ciliary neurotrophic factor (CNTF) is a potent survival factor for neurons and oligodendrocytes and may be relevant in reducing tissue destruction during inflammatory attacks. Subjects and Methods: We screened 288 unselected patients with multiple sclerosis (MS) (mean age, 40.2 +/- 10.2 years; range, 18-71 years) for a previously described homozygous null mutation within the CNTF gene leading to a truncated, biologically inactive protein. The G-to-A CNTF null mutation at position -6 of the second exon was identified by a HaeIII polymorphism of the polymerase chain reaction-amplified genomic DNA. Results: The homozygous CNTF null mutation (CNTF-/-) was found in 7 (2.4%) of the 288 randomly selected patients with MS. Patients with the CNTF-/-genotype had a significantly earlier onset of disease (17 vs 27 years; Mann-Whitney test, P = .007) with predominant motor symptoms. Conclusions: These results suggest that CNTF contributes to time and site of early clinical manifestation. The frequency of patients with MS with a homozygous CNTF null mutation in this population was not higher than in control groups, indicating that the CNTF null mutation is not a risk factor for development of MS.