Familial multiple sclerosis in Greece: Distinct clinical and imaging characteristics in comparison with the sporadic disease.

Objective: Few studies are available worldwide concerning clinical, imaging and genetic/immunogenetic profile of familial multiple sclerosis (fMS). Recent but not systematic data concerning fMS, without direct comparison to sporadic MS (sMS) drove our aim towards further research in the field, given the total lack of information for the Greek population as well. Thus, in this case-control study we examined the clinical and imaging characteristics of 102 fMS-patients, compared to 282 patients suffering sMS.

Patients And Methods: Patients recruited underwent medical interview (demographic, clinical and family history data collected). They were also assessed for disability and their MRI-scans were analyzed for lesion distribution. Statistical analyses were performed using SPSS v.21.0 software.

Results: 49% of unrelated fMS cases had at least one 1 degree relative affected, while the rest had also at least one relative with MS, 3 degree or closer. Only the former subgroup (1 degree relative) and not the entire fMS sample, had significantly younger age at onset (AAO) compared to sMS cases (mean AAO 28.08 vs 31.33 years, p = 0.036). AAO anticipation was noted in younger generation fMS patients (mean AAO 24.67 years in younger generation vs 37 years in older generation, p = 0.001). With regard to our MRI findings, subcortical lesions were less frequent in fMS (71% in fMS vs 81.9% in sMS patients, p = 0.028), whereas cervical cord lesions more frequent (93% in fMS vs 79.9% in sMS patients, p = 0.033, only in the 1 degree relative subgroup). Double vision was a less common first symptom in fMS (4.1% in fMS vs 14.8% in sMS patients, p = 0.005). 1 degree relatives of fMS patients were more often diagnosed with Hashimoto's (8.9% in fMS relatives vs 3.3% in sMS relatives, p = 0.033).

Conclusion: Younger AAO and different lesion distribution in brain and possibly spinal cord was observed in fMS in comparison to sMS patients. The hypothesis of increased genetic burden in fMS could offer some explanation for these differences, which needs though further validation as a next step, through genetic/immunogenetic testing in larger cohorts, of different ethnic groups.