Aidar Akaev's lawyers Galina Skripkina and Cholponbek Aitbaev today filed an appeal with a Bishkek district court.
Skripkina says the commission should have waited for the parliament's go-ahead before making a decision.
In an interview with RFE/RL's Kyrgyz Service, Aitbaev cited other irregularities that, in his view, make the CEC ruling "illegal."
"Should [election commission members] have invited [Aidar] Akaev to their session, he or his representatives would have been able to defend his interests," Aitbaev said. "Since that did not happen, the right a lawmaker has to defend his or her interests have been directly violated."
The commission voted on October 5 to strip Aidar Akaev of his legislative mandate, arguing that he no longer lives in the country.
But Skripkina told reporters today the commission should have waited for the parliament's go-ahead before making a decision.
The commission also stripped another legislator, Muratbek Malabaev, of his parliamentary seat. Malabaev is reportedly close to the Akaev family and currently lives in Moscow.
Both Malabaev and Aidar Akaev won parliamentary seats in the disputed 2005 legislative polls that led to President Akaev's ousting and flight to Russia with his relatives.