Developmental and epileptic encephalopathy with dyskinesia caused by the FRRS1L gene mutation: a case report and literature review / 中华实用儿科临床杂志

ABSTRACT

The clinical characteristics and gene mutation profiles of a child who was treated in Xuzhou Children′s Hospital, Xuzhou Medical University in June 2022 due to developmental and epileptic encephalopathy (DEE) combined with dyskinesia caused by the FRRS1L gene mutation was analyzed retrospectively.A male case 1 year and 9 months old presented developmental delay since childhood, hypotonia at the age of 6 months, treatment-resistant seizures (focal clonic seizures) at the age of 1 year and 7 months that were unable to be controlled by antiepileptic drugs, and developmental regression and abnormal movements of the hands and feet during the attack.Whole exome sequencing showed 2 heterozygous variants (missense mutation and deletion mutation) in the FRRS1L gene of the child.The missense mutation c. 754C>T (p.R252C) located in the 4 th exon was inherited from his mother, and the deletion mutation c. 438_c.459del (p.I146fs*4) located in the 2 th exon was inherited from his father, thus constituting a compound heterozygous mutation.Through literature review, all 6 relevant literatures involving 31 children with DEE were published in foreign countries.They presented similar clinical manifestations to this case, but the genotypes were different, all of which were homozygous mutations.The FRRS1L gene mutation can lead to DEE, which is characterized by the autosomal recessive inheritance pattern, refractory epilepsy onset in infancy, developmental regression and prominent dyskinetic movements with hyperkinesia, and poor long-term prognosis.