Objective To explore the clinical manifestation and genetic attributes of pediatric patients with epilepsy and developmental backwardness associated with CACNA1A gene variants. Methods The medical records of 12 pediatric patients with CACNA1A gene variant-associated epilepsy with or without developmental backwardness admitted to the Department of Pediatric Internal Medicine of the Third Affiliated Hospital of Zhengzhou University from January 2019 to January 2024 were retrospectively collected， including the type of epileptic seizures， imaging examinations， electrophysiological characteristics， Griffiths Development Scales-Chinese Edition （GDS-C） scores， therapeutic effects， and genetic test results， and clinical and genetic characteristics were analyzed. Peripheral blood was collected from the pediatric patients and their parents， genomic DNA was extracted， whole exome genome sequencing was performed in the family line. Sanger sequencing was used to validate the variant loci and clarify the sources of variants. Results The median age of onset for the 12 pediatric patients with epilepsy was 28.7 months， and the type of seizure was focal and/ or generalized. Among 12 cases， there were 10 cases of missense mutations， one case of mutation near splice site， and one case of mutation in non-coding region. There were four cases of de novo mutations and 8 cases of hereditary mutations. Three cases had a history of status epilepticus. Three cases had cluster seizures during the course of the disease. One case of acute encephalopathy after sustained status epilepticus， with ataxia and tremor of the limbs after awakening. One case had a stroke-like episode. There were 10 cases of abnormal EEG discharges during the interictal period. Ten pediatric patients had varying degrees of developmental delay. After antiepileptic drug treatment， seizures resolved in six cases， and intermittent seizures remained in the remaining six cases. Conclusions CACNA1A gene variant-associated epilepsy may present as focal and/or generalized seizures， often with developmental backwardness， and valproic acid， levetiracetam， and lamotrigine are effective in some pediatric patients. Clinical manifestations and therapeutic effects of epilepsy associated with mutations at different variant loci of the CACNA1A gene differ.