ObjectiveTo explore the clinical, genetic and prognostic features of early infantile epileptic encephalopathy caused by DNM1 gene pathogenic variations.MethodsClinical phenotype, genotype and prognosis of 3 individuals with de novo variants in DNM1 gene were analyzed retrospectively. Through using “Dynamin-1” or “DNM1” as key words to search literature at database of China National Knowledge Infrastructure, Wanfang, PubMed and OMIM. Genotype-phenotype correlations were analyzed by analysis of variance (ANOVA).ResultAmong the 3 patients, 1 female and 2 males. 2 cases with epileptic spasm and 1 case with focal clonic seizure or secondary generalized tonic-clonic seizure were manifested with onset age from 2 to 17 months. De novo variants at NM_004408.4: c.415 G>A(P. Gly 139Arg) in 2 inviduals and NM_004408.4: c.545 C>A(P. Ala 182Asp)in 1 invidual of DNM1 gene were identified by gene testing. After follow-up at age of 2~3 years, all patients were presented with hypotonia, severe intellectual disability, non-verbal, non-ambulatory, drug-resistant epilepsy and feeding difficulties. 36 cases with pathogenic DNM1 variants were reported by far, totally 39 cases were included. Of the 39 patients, hypotonia were found to be independent of the locus of genetic variants, while those inviduals with variants in the GTPase and middle domains almost presented severe or profound intellectual disability and epilepsy. 31 patients diagnosed with epilepsy and complete clinical data were further analyzed, epileptic spasm was the most common types of seizure. Absent seizure was significantly more common in those patients with variants in the GTPase domains (P=0.02), compared to those patients with variants in the middle domains. No statistical differences were found in gender, onset age, other types of seizure and drug treatment response between variants in the GTPase and middle domains.ConclusionHypotonia, early onset epilepsy, severe intellectual and movement disability were the common features in patients with DMN1 related encephalopathy. Epileptic spasm was the most common types of seizure, no significant differences were found in the phenotype between the GTPase and middle domains expect for absent seizure. Our patients also presented with feeding difficulties.
Severe psychomotor developmental delay resulting from early postnatal (within 3 months) seizures can be diagnosed as Early-Infantile Developmental and Epileptic encephalopathies (EIDEE). Its primary etiologies include structural, hereditary, metabolic and etc. The main pathogenesis may be related to the inhibition of normal physiological activity of the brain by abnormal electrical activity and the damage of the brain neural network. Ohtahara syndrome and Early Myoclonic Encephalopathy (EME) are typical types of EIDEE. The principle of treatment is to improve the cognitive and developmental function by controlling frequent seizures. When the seizure is difficult to control with drugs, surgical evaluation should be performed as soon as possible, and surgical treatment is the first choice for patients suitable for surgery. The types of surgery can be divided into excision surgery, dissociation surgery, neuromodulation surgery and etc. The current status of surgical treatment of EIDEE was described, and the curative effect of surgical treatment was explored, so as to help clinicians choose appropriate treatment methods.