1Seyedmohammad Baghbanian, 1Hadis Alinejad, 2Sharareh Eskandarieh, 2Mohammadali Sahraian

1Mazandaran University Of Medical Sciences, Sari, Iran; 2Tehran University Of Medical Sciences, Tehran, Iran


Mazandaran is a Caspian province in the north of Iran and with a population of more than three million people. The Mazanderani people’s ancestors came from the Caucasus region, perhaps displacing an earlier group in the South Caspian1. Multiple sclerosis prevalence and incidence rates have increased in Mazandaran province in the past ten years2. There is limited data on familial M.S and the relationship between factors related to it.

Design and Method(s):

In this population-based cross-sectional study, MS patients (according to McDonald criteria) from Mazandaran province who have been registered in the Iranian national registry program3 from 20 March 2018 to 21 September 2020 were included. The aim of this study was to investigate the prevalence of the familial form of MS and to compare the level of disability of familial form with sporadic form.


Of 1750 patients included in this study, 261 (14.9%) cases had a family history of M.S. Age was significantly higher in the familial group (P-value = 0.02). Sibling relationship was the most common (46%). The patient’s sister was most likely to be involved in 46 (18.9%). In the familial group, 209(83.9%) cases had one affected family member, 33(13.3%) cases had two affected family members, and 7 (2.8%) cases had three or more affected family members. Of note, after first-degree relatives, 97(40%), maternal relatives 62(25%), and paternal relatives 47(19%) involvement were observed in the order of frequency. In our assessments, the risk of having a child with MS increases when three or more of the family members have MS. Our observations showed that the average disability rate of patients with a family history is higher than patients without a family history. (P-value<0.001).


The prevalence of familial M.S in Mazandaran province can be considered as one of the highest reports of familial MS in Iran. It was more than that of the global familial M.S. rate (12.9%). One of the reasons for the higher prevalence of familial MS in this region may be the high probability of consanguineous marriage between these people4. However, differences in environmental factors cannot be ignored. Higher mean disability in familial MS compare to nonfamilial in this study may suggest that a potent drug is better to start at the beginning of treatment in patients with a positive family history.