Abstracts

Rationale: Nowadays, diverse researchers search a phenotype-genotype association for epilepsy. These investigations seek to identify genetic alterations that may be associated with specific clinical features. This will allow an early diagnosis, provide timely treatment and thus avoid comorbidities of the evolution of epilepsy. Our goal was to identify the inheritance pattern through which mesial temporal lobe epilepsy (MTLE) is segregated in Mexico; as well as to find an association between the inheritance pattern and the clinical picture. Methods: We included families with ≥ 2 members affected with MTLE whose family history was the only risk factor during January 2015 to December of 2017. Complete medical records were performed and reviewed to confirm the MTLE diagnosis. Subsequently, a family degree was created for each family. The inheritance pattern in families was classified as autosomal dominant (AD) when affected members were observed in more than one generation and in at least one parent (vertical transmission), and autosomal recessive (AR) when affected members were in a single generation and both parents are unaffected (horizontal transmission). Finally, we carried out a descriptive analysis of the clinical data and tests such as Fisher exact test, chi-squared test and logistic regression analysis. The above tests were performed in order to determine association and differences between clinical characteristics and inheritance pattern, both dominant and recessive. Results: We included 25 families with 61 MTLE affected members. A prevalence of AD pattern (68%) was identified versus  AR pattern (32%). We found a statistically significant difference between the age at seizure onset on families with AD pattern vs AR pattern (p=0.0002, t-student test). There is an association between an age at onset of 5 years or less with the AD pattern (p=0.002, chi-squared test). We also observed that families with AD pattern are more likely to start seizures at 5 years or earlier (OR = 15.7, IC 95% = 1.9-128.9; p = 0.01, Wald's test). Conclusions: The age at seizure onset is a clinical variable that can be different among affected members of the same family or among families. However, we observed that it tends to be similar when the inheritance pattern is shared; this suggests that the age at seizure onset may be determined by genetic inheritable factors, different to the factors that determine a specific epilepsy type. This study could be used as reference to perform genetic molecular studies which allow identifying and understanding such genetic factors, which for the time being are still unknown. Funding: No funding