Genetic Epidemiology Of Multiple Sclerosis
Ann Neurol 1994 Dec;36 Suppl 2:S194-203
Univ of British Columbia, Dept of Medical Genetics, Vancouver, Canada
PMID# 7998788; UI# 95091472
The possible role of Genetic factors in the Etiology of Multiple Sclerosis (MS) has been debated for over a century.
It is now clear that Genetic and environmental interactions must exist. It is likely that MS susceptibility is under the control of several Genes encoded both within and outside the Major Histocompatibility Complex (MHC).
It is therefore unlikely that MS has a purely transmissible cause for these and other reasons, including:
- the low concordance rate in dizygotic twins,
- low concordance rate in conjugal pairs,
- negative birth order in multiplex MS sibships,
- the relatively high rate of MS in second - and third-degree relatives of MS patients,
- the identification of groups resistant to MS in otherwise high-risk areas
Geographic Similarities Between Varicella And Multiple Sclerosis: An Hypothesis On The Environmental Factor Of Multiple Sclerosis
Ross RT, Cheang M
J Clin Epidemiol 1995 Jun;48(6):731-7
Univ of Manitoba, Faculty of Medicine, Section of Neurology, Winnipeg, Canada
PMID# 7769403; UI# 95287170
The environmental factor causing Multiple Sclerosis (MS) is unknown. Kurtzke et al. (Neurology 1979; 29: 1228-1235) depicted a north to south diminishing gradient in the case/control ratios for MS among American veterans in the United States.
A similar, but less precise, gradient emerged when the incidence rates of Varicella from 37 states during 1978-91 were compared.
A loose correlation appears to exist between the mean incidence of Varicella and the MS risk ratio (n = 0.344 Spearman rank correlation coefficient, p = 0.037).
Further, the data on the fate of migrants moving from a high risk MS country to a low risk country and the reverse, plus the great importance of the age at migration, raise the question of a possible connection between the two diseases.
Because of these Epidemiological and other similarities between the two diseases a further comparative study was suggested.
Dean G, Bhigjee AI, Bill PL, Fritz V, Chikanza IC, Thomas JE, Levy LF, Saffer D
J Neurol NeuroSurg Psychiatry 1994 Sep;57(9):1064-9
Medico-Social Research Board, Dublin, Ireland
PMID# 8089669; UI# 94376095
Multiple Sclerosis is rare among the indigenous black people of Africa. The first account of a black patient with Multiple Sclerosis in South Africa was published as late as 1987.
Since then a search to find black patients with Multiple Sclerosis in Southern Africa has continued.
Seven black patients have now been traced in South Africa and five in Zimbabwe in whom a diagnosis of Multiple Sclerosis can be accepted. Six of the 12 patients became blind, or nearly so, from severe Optic Neuritis.
Multiple Sclerosis in these few black patients more often resembled the disorder as it occurs in Oriental people than among white people in southern Africa or the black people of North America or the Caribbean.
Higher Than Expected Prevalence Of Multiple Sclerosis In Northern Colorado: Dependence On Methodologic Issues
Nelson LM, Hamman RF, Thompson DS, Baum HM, Boteler DL, Burks JS, Franklin GM
PMID# 3489193; UI# 86311552
A population-based study of Multiple Sclerosis (MS) was conducted in 2 northern Colorado counties in 1982 to determine MS prevalence, to compare the rates with recent North American surveys and to compare the methods used in these studies.
Provisional cases were identified from: the patient rolls of MS service organizations, chart reviews in 2 neurology practices, a survey of physicians and a review of hospital discharge diagnoses. Crude-point prevalence for the 2-county region was 84 per 100,000.
The age-adjusted rate was higher than the rate for the region above the 37th parallel projected from data in a 1976 national survey, but was comparable to rates obtained in localized surveys conducted in the northern tier of the country.
The methodological results revealed that the highest yield sources were the MS service organizations and the neurology practice chart reviews.
MS prevalence surveys which neglect these methods may underestimate MS prevalence by as much as 20-40%.
Multiple Sclerosis Sibling Pairs: Clustered Onset And Familial Predisposition
Doolittle TH, Myers RH, Lehrich JR, Birnbaum G, Sheremata W, Franklin GM, Nelson LM, Hauser SL
Neurology 1990 Oct;40(10):1546-52
Massachusetts General Hospital, NeuroImmunology Unit, Boston 02114
PMID# 2215946; UI# 91015770
We evaluated 48 Relapsing/Remitting Multiple Sclerosis (Relapsing/Remitting MS) sibling pairs derived from 44 families for age and date of onset of MS symptoms, clinical course, and family history of MS.
Age and sex-matched R/R MS clinic patients provided a statistical comparison group. The age of onset tended to cluster within multiplex families. The initial symptom of MS occurred within 5 years of age in 30/48 sibling pairs compared with 16/48 controls.
A positive family history of MS (other than siblings) was present in 43% of the multiplex families compared with 20% among simplex controls.
In 1st-, 2nd-, and 3rd-degree relatives who had lived into the age at risk, 22/1,134 family members of multiplex sibling pairs had probable or definite MS compared with 10/1,215 control family members.
Age of onset clustering in siblings concordant for R/R MS and an increased risk of MS in other family members suggest that factors influencing disease onset may be in part inherited in these kindreds.