Objective:To investigate the clinical characteristics and gene mutation of seven cases of CDKL5 gene related early-onset epileptic encephalopathy diagnosed by next-generation sequencing.Methods:The clinical data of children with early-onset epileptic encephalopathy from February 2018 to December 2019 in the Department of Neurology, Children′s Hospital Affiliated to Zhengzhou University were retrospectively analyzed. The whole exome sequencing method was used to analyze the entire exome of the proband, and seven cases of CDKL5 gene mutation positive were screened out, and Sanger sequencing verification on family members was performed to identify the source and the characteristics of gene mutations were analyzed.Results:Among the seven children diagnosed with CDKL5 gene related early-onset epileptic encephalopathy, the ratio of male to female was 2∶5, and the age of onset was 15 days to five months of birth. The clinical phenotypes all included different degrees of developmental delay and repeated seizures, which were manifested as general seizures, myoclonic seizures, convulsive seizures or focal seizures; the outcome of use of antiepileptic drugs to control seizures was poor, and some applications of ketogenic diet had better effects. CDKL5 gene mutation sites were all denovo mutations, including NM_003159: c.772_776del (p.K258Efs *10) frameshift mutation, NM_003159.2 (exon: 9-15) heterozygous deletion, CDKL5 hemizygous deletion, NM_003159: c.268 (exon5) G>T (p.E90 *, 941) and NM_003159: c.2578C>T (p.Q860 *, 171) nonsense mutation, NM_003159: c.211A>G (p.Asn71Asp) and NM_001323289: c.545T>C (p.L182P) missense mutation. Among them, c.772_776del (p.K258Efs *10), c.268 (exon5)G>T and c.2578C>T (p.Q860 *, 171) have not been reported. Conclusions:CDKL5 gene related early-onset epileptic encephalopathy is an early onset epilepsy, which is more common in women, and has different forms of seizures. The early electroencephalogram is characterized as severe abnormal brain discharge, and the disease progresses in various forms. There are no specific changes in head magnetic resonance imaging. Different gene mutation sites may lead to different phenotypes and prognostic differences. Many anti-epileptic treatments are ineffective, and ketogenic diets are effective for some patients.

Objective:To summarize the clinical phenotype and genetic characteristics of a case of autosomal dominant mental retardation-42 (MRD42) caused by GNB1 gene mutation. Methods:The clinical and genetic data of a case of MRD42 caused by a GNB1 gene missense mutation diagnosed in the Department of Neurology, Children′s Hospital Affiliated to Zhengzhou University in March 2023 were retrospectively analyzed. The child was followed-up, the child′s data were summarized, and related literature was reviewed. Results:The patient is a 6-month-old female infant, who was admitted to hospital because of "developmental delay for 3 months, intermittent convulsions for 1 month". The clinical manifestations included generalized tonic-clonic seizures, focal seizures, intellectual disability, delayed language and motor development. Long-term video electroencephalogram showed slightly slower background activity, bilateral occipital spike and wave discharges, multispike and wave complexes during sleep. Three focal onset seizures were captured. Cranial magnetic resonance imaging suggested that the subarachnoid space of the bilateral frontotemporal areas was slightly wide. Chromosome karyotype and copy number variation analysis showed no abnormality. The results of whole exon sequencing showed a de novo heterozygous missense mutation in the GNB1 gene [NM_002074:c.155(exon5)G>A;p.Arg52Gln], which had not been reported. The seizure was effectively controlled by function rehabilitation training and anti-epileptic drug therapy. Conclusions:MRD42 is a rare autosomal dominant disorder caused by mutation in the GNB1 gene. The clinical manifestations include infantile-onset seizures, mental retardation, speech and motor development delay, etc. The de novo heterozygous missense mutation in the GNB1 gene c.155G>A(p.Arg52Gln) is the genetic cause of the proband.