It has been established that alterations in cyclin-dependent kinase-like 5 (<i>CDKL5</i>) or forkhead box protein G1 (<i>FOXG1</i>) correspond to distinct neurodevelopmental disorders, given that a series of studies have indicated that RTT is also caused by alterations in either one of these genes.
The results from the study will help to undertake further research on the role of phosphorylated CDKL5 in the onset of neurodevelopmental disorders caused by mutations in higher eukaryotic systems.
The purpose of this study was to evaluate the frequency of mosaicism detected by next-generation sequencing in genes associated with epilepsy-related neurodevelopmental disorders.MethodsWe conducted a retrospective analysis of 893 probands with epilepsy who had a multigene epilepsy panel or whole-exome sequencing performed in a clinical diagnostic laboratory and were positive for a pathogenic or likely pathogenic variant in one of nine genes (CDKL5, GABRA1, GABRG2, GRIN2B, KCNQ2, MECP2, PCDH19, SCN1A, or SCN2A).
These results suggest a novel role for CDKL5 in the regulation of synaptic function and uncover an intriguing microcircuit mechanism underlying impaired learning and memory.<b>SIGNIFICANCE STATEMENT</b> Cyclin-dependent kinase-like 5 (CDKL5) deficiency is a severe neurodevelopmental disorder caused by mutations in the <i>CDKL5</i> gene.
Mammalian models of CDKL5 disorder are currently limited to mouse, and little is known about Cdkl5 in other organisms used to model neurodevelopmental disorders, such as rat.
Cyclin-dependent kinase-like 5 (CDKL5) is a Ser/Thr protein kinase primarily expressed in the central nervous system and is known to cause X-linked neurodevelopmental disorders such as Rett syndrome.
The cyclin-dependent kinase-like 5 (CDKL5) gene has been associated with rare neurodevelopmental disorders characterized by the early onset of seizures and intellectual disability.
We identified disease-causing mutations in known genes associated with neurodevelopmental disorders including GNAO1 and CDKL5 in two of four individuals.
An involvement of the immune system has been suggested in Rett syndrome (RTT), a devastating neurodevelopmental disorder related to oxidative stress, and caused by a mutation in the methyl-CpG binding protein 2 gene (MECP2) or, more rarely, cyclin-dependent kinase-like 5 (CDKL5).
Rett syndrome (RTT), a neurodevelopmental disorder affecting exclusively (99%) female infants, is associated with loss-of-function mutations in the gene encoding methyl-CpG binding protein 2 (MECP2) and, more rarely, cyclin-dependent kinase-like 5 (CDKL5) and forkhead box protein G1 (FOXG1).
The association of CDKL5 with neurodevelopmental disorders and its high expression levels in the maturing brain underscore the importance of this kinase for proper brain development.
We sequenced BCAs in patients with autism or related NDDs, revealing disruption of 33 loci in four general categories: (1) genes previously associated with abnormal neurodevelopment (e.g., AUTS2, FOXP1, and CDKL5), (2) single-gene contributors to microdeletion syndromes (MBD5, SATB2, EHMT1, and SNURF-SNRPN), (3) novel risk loci (e.g., CHD8, KIRREL3, and ZNF507), and (4) genes associated with later-onset psychiatric disorders (e.g., TCF4, ZNF804A, PDE10A, GRIN2B, and ANK3).
Mutations of the cyclin-dependent kinase-like 5 (CDKL5) and netrin-G1 (NTNG1) genes cause a severe neurodevelopmental disorder with clinical features that are closely related to Rett syndrome, including intellectual disability, early-onset intractable epilepsy and autism.
This study demonstrated the importance of CDKL5 mutations as etiological factors in neurodevelopmental disorders, and indicated that a thorough analysis of the CDKL5 gene sequence and its rearrangements should be considered in females with Rett syndrome-like phenotypes, severe encephalopathy and epilepsy with onset before 5 months of age.
The screening was negative for all men as well as for women with Aicardi syndrome, excluding the CDKL5 gene as a candidate for this neurodevelopmental disorder.
Mutations in the human X-linked cyclin-dependent kinase-like 5 (CDKL5) gene have been shown to cause severe neurodevelopmental disorders including infantile spasms, encephalopathy, West-syndrome and an early-onset variant of Rett syndrome.
Mutations in the X-linked cyclin-dependent kinase-like 5 (CDKL5) gene have recently been reported in patients with severe neurodevelopmental disorder characterized by early-onset seizures, infantile spasms, severe psychomotor impairment and very recently, in patients with Rett syndrome (RTT)-like phenotype.
The mutations are located within the protein kinase domain and affect highly conserved amino acids; this strongly suggests that impaired CDKL5 catalytic activity plays an important role in the pathogenesis of this neurodevelopmental disorder.