A novel DOCK7 variant as a rare reason for epileptic encephalopathy, cortical blindness, dysmorphic features: A case report and brief review of the literature

A novel DOCK7 variant as a rare reason for epilepticencephalopathy, cortical blindness, dysmorphicfeatures: A case report and brief review of theliterature1Özlem Özsoy, 2Tayfun Cinleti, 3Selcan Zeybek, 1Didem Soydemir, 1Gamze SarıkayaUzan, 1Çağatay Günay, 1,4,5Semra Hız Kurul, 1Uluç Yiş1Department of Pediatric Neurology, Faculty of Medicine and 2Department of Pediatric Genetics,Dokuz Eylül University, İzmir; 3Department of Medical Genetics, Tınaztepe University Faculty ofMedicine, Izmir; 4İzmir Biomedicine and Genome Center, 5İzmir International Biomedicine and GenomeInstitute, Dokuz Eylül University Health Campus, İzmir, TurkeyAbstractEarly infantile epileptic encephalopathy 23 (EIEE23; OMIM #615859) is a rare autosomal recessivedisorder. It is characterized by refractory seizures, multifocal epileptic activity on electroencephalography,psychomotor development delay, dysmorphic facial features and cortical blindness/visual impairment.DOCK7 is involved in intracellular signaling networks and plays a role in axon formation and neuronalpolarization. Function loss of this gene has previously been described in the molecular etiology ofEIEE23. Here, we report a boy with a pathogenic novel variant in the DOCK7 gene presenting with,infantile-onset epileptic encephalopathy, severe neurodevelopmental delay, dysmorphic facial features,cortical blindness as well as previously unreported minor dental and extremity anomalies. Few caseswith DOCK7 mutations have been reported in the literature. Due to its high genetic heterogeneity andscarcity, it is extremely important to report a novel and specific mutations and their associated clinicalphenotypes. Whole exome sequencing revealed a novel pathogenic homozygous frameshift variantwhich has not been reported (c.5669dup (p.Cys1891ValfsTer2) mutation in the exon 44 of DOCK7).Keywords: DOCK7, epileptic encephalopathy, cortical blindness, dysmorphism, novel mutation