The British Isles survey of multiple sclerosis in twins

Abstract

During a 27-month recruitment period, we identified 146 individuals with multiple sclerosis (MS) who have a twin. A single clinician interviewed and examined 105 pairs of twins, and we confirmed zygosity using minisatellite probes. Including two suspected cases, 11 of 44 (25%) monozygotic twin pairs were concordant compared with two of 61 (3%) dizygotic twin pairs--two of 33 (6%) like-sexed and zero of 28 (0%) opposite-sexed. MRI was performed in 64 of 105 co-twins, and showed abnormalities consistent with demyelination in 13% of monozygotic and 9% of dizygotic co-twins who were clinically unaffected. These findings are similar to the results of most previous studies of MS in twins in which zygosity was not unequivocally established and where the majority of clinically unaffected co-twins were not studied by MRI; the difference in concordance rates in monozygotic and dizygotic twins indicates a significant genetic component in the etiology of MS.

Multiple sclerosis genetics

“…The percentage of concordance for monozygotic twins is approximately 25-30% whereas the concordance percentage for dizygotic twins is 3-5% (Ebers et al, 1986(Ebers et al, , 1995(Ebers et al, , 2004Mumford et al, 1994;Willer et al, 2003;Hansen et al, 2005;Islam et al, 2006;Ristori et al, 2006). This concordance rate for fraternal twins is greater than that of other first-degree relatives of MS patients but is still far less than that of identical twins (Willer et al, 2003).…”

A genome-wide screen for linkage in Nordic sib-pairs with multiple sclerosis

“…Although the exact cause of multiple sclerosis is unknown, epidemiological studies indicate a multifactorial aetiology 1 with the involvement of genetic factors suggested by studies in twins, 2,3 half-siblings, 4 adoptees 5 and conjugal pairs. 6,7 The role of major histocompatibility complex (MHC) class II alleles is well established, 8 but no other candidate genes have consistently been linked or associated with the disease.…”

Western lifestyle and immunopathology of multiple sclerosis

“…Some studies revealed a higher concordance rate between identical (monozygotic) compared with nonidentical (dizygotic) pairs (approximately 25–30% in monozygotic versus 5% in dizygotic twins) 50, 51. In contrast, other studies showed equivalent concordance rates 52, 53…”