scholarly journals KCNQ2 mutations: genotype-phenotype association beyond epilepsy

2015 ◽  
Vol 42 (S1) ◽  
pp. S8-S8
Author(s):  
SE Buerki ◽  
GA Horwath ◽  
MI Van Allen ◽  
A Datta ◽  
C Boelman ◽  
...  
Keyword(s):  
Developmental Delay ◽  
Autonomic Dysfunction ◽  
De Novo ◽  
Focal Epilepsy ◽  
Missense Variant ◽  
Epileptic Encephalopathy ◽  
Global Developmental Delay ◽  
High Signal ◽  
Brain Volume Loss ◽  
Hyperkinetic Movement Disorder

Background: KCNQ2 abnormalities were described in infants with benign familial neonatal seizures (BFNS) and epileptic encephalopathy (EE). Associated features possibly include abnormal neuroimaging findings such as hypomyelination and/or T2 high signal of basal ganglia. Methods: This report describes 4 infants carrying different heterozygous KCNQ2 variants and 2 infants with 20q13.33 deletions encompassing KCNQ2 gene. Results: The different KCNQ2 mutations led to EE in 3 patients and included a novel de novo missense variant, p.Arg201Cys/c.601C>T, in an infant with severe EE and global developmental delay, hyperkinetic movement disorder, autonomic dysfunction with chronic hypoventilation, apnea, low GABA levels in CSF, and hypomyelination. She died at age 3 years of respiratory failure. One patient with BFNS and normal MRI has a previously reported c.508delG frame shift mutation in KCNQ2. Of the two de novo 22q13.33 deletions (1.2Mb versus 254.1 Kb) the larger caused a more severe phenotype, including focal epilepsy from infancy until 4 years, moderate developmental delay and diffuse brain volume loss. Conclusions: Along with varied epilepsy phenotypes and neuroimaging findings KCNQ abnormalities were associated with severe autonomic dysfunction and reduced CSF GABA levels. This might have further treatment implications, besides that the altered potassium channel function itself presents a therapeutic target.

scholarly journals X-linked neonatal-onset epileptic encephalopathy associated with a gain-of-function variant p.R660T in GRIA3

PLoS Genetics ◽  
2021 ◽  
Vol 17 (6) ◽  
pp. e1009608
Author(s):  
Jia-Hui Sun ◽  
Jiang Chen ◽  
Fernando Eduardo Ayala Valenzuela ◽  
Carolyn Brown ◽  
Diane Masser-Frye ◽  
...  
Keyword(s):  
Developmental Delay ◽  
Prolonged Exposure ◽  
De Novo ◽  
Missense Variant ◽  
Epileptic Encephalopathy ◽  
Global Developmental Delay ◽  
Decay Kinetics ◽  
Gain Of Function ◽  
Ca1 Neurons ◽  
Pathogenic Variants

The X-linked GRIA3 gene encodes the GLUA3 subunit of AMPA-type glutamate receptors. Pathogenic variants in this gene were previously reported in neurodevelopmental diseases, mostly in male patients but rarely in females. Here we report a de novo pathogenic missense variant in GRIA3 (c.1979G>C; p. R660T) identified in a 1-year-old female patient with severe epilepsy and global developmental delay. When exogenously expressed in human embryonic kidney (HEK) cells, GLUA3_R660T showed slower desensitization and deactivation kinetics compared to wildtype (wt) GLUA3 receptors. Substantial non-desensitized currents were observed with the mutant but not for wt GLUA3 with prolonged exposure to glutamate. When co-expressed with GLUA2, the decay kinetics were similarly slowed in GLUA2/A3_R660T with non-desensitized steady state currents. In cultured cerebellar granule neurons, miniature excitatory postsynaptic currents (mEPSCs) were significantly slower in R660T transfected cells than those expressing wt GLUA3. When overexpressed in hippocampal CA1 neurons by in utero electroporation, the evoked EPSCs and mEPSCs were slower in neurons expressing R660T mutant compared to those expressing wt GLUA3. Therefore our study provides functional evidence that a gain of function (GoF) variant in GRIA3 may cause epileptic encephalopathy and global developmental delay in a female subject by enhancing synaptic transmission.

scholarly journals A novel de novo KDM5C variant in a female with global developmental delay and ataxia: a case report

BMC Neurology ◽  
2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Natalie C. Lippa ◽  
Subit Barua ◽  
Vimla Aggarwal ◽  
Elaine Pereira ◽  
Jennifer M. Bain
Keyword(s):  
Case Report ◽  
Intellectual Disability ◽  
Short Stature ◽  
Developmental Delay ◽  
De Novo ◽  
Phenotypic Variability ◽  
Missense Variant ◽  
Global Developmental Delay ◽  
Related Disorder ◽  
Patient Reported

Abstract Background Pathogenic variants in KDM5C are a cause of X-linked intellectual disability in males. Other features in males include short stature, dysmorphic features, seizures and spasticity. In some instances, female relatives were noted to have learning difficulties and mild intellectual disabilities, but full phenotypic descriptions were often incomplete. Recently, detailed phenotypic features of five affected females with de novo variants were described. (Clin Genet 98:43–55, 2020) Four individuals had a protein truncating variant and 1 individual had a missense variant. All five individuals had developmental delay/intellectual disability and three neurological features. Case presentation Here we report a three-year-old female with global developmental delay, hypotonia and ataxia. Through whole exome sequencing, a de novo c.1516A > G (p.Met506Val) variant in KDM5C was identified. This missense variant is in the jumonji-C domain of this multi domain protein where other missense variants have been previously reported in KDM5C related disorder. The KDM5C gene is highly intolerant to functional variation which suggests its pathogenicity. The probands motor delays and language impairment is consistent with other reported female patients with de novo variants in KDM5C. However, other features reported in females (distinctive facial features, skeletal abnormalities, short stature and endocrine features) were absent. To the best of our knowledge, our proband is the first female patient reported with a diagnosis of ataxia. Conclusions This case report provides evidence for an emerging and phenotypic variability that adds to the literature of the role of KDM5C in females with neurodevelopmental disorders as well as movement disorders.

scholarly journals Spectrum of Movement Disorders in GNAO1 Encephalopathy: in-depth Phenotyping and Literature Review

2020 ◽  
Author(s):  
Soo Yeon Kim ◽  
YoungKyu Shim ◽  
Young Joon Ko ◽  
Soojin Park ◽  
Se Song Jang ◽  
...  
Keyword(s):  
Literature Review ◽  
Exome Sequencing ◽  
Developmental Delay ◽  
Whole Exome Sequencing ◽  
De Novo ◽  
Neurodevelopmental Disorder ◽  
Epileptic Encephalopathy ◽  
Global Developmental Delay ◽  
Pathogenic Variants ◽  
Whole Exome

Abstract Background GNAO1 encephalopathy is a rare neurodevelopmental disorder characterized by distinct movement presentations and early onset epileptic encephalopathy. Here, we report the in-depth phenotyping of genetically confirmed patients with GNAO1 encephalopathy, focusing on movement presentations. Results Six patients who participated in Korean Undiagnosed Disease Program were diagnosed to have pathogenic or likely pathogenic variants in GNAO1 using whole exome sequencing. All medical records and personal video clips were analyzed with a literature review. Three of the 6 patients were male. Mean follow-up duration was 39 months (range, 7–78 months) and age at last examination was 8.0 years (range, 3.3–16.9 years). Initial complaints were hypotonia or developmental delay in 5 and right-hand clumsiness in 1 patient, which were noticed at 20 months of age on average (range, 0–75 months). All patients showed global developmental delay and 4 had severely retarded development. Five patients (5/6, 83.3%) had many different movement symptoms with various onset and progression. The symptoms included stereotyped hands movement, non-epileptic myoclonus, dyskinesia, dystonia and choreoathetosis. Whole exome sequencing identified 6 different variants in GNAO1. Three were novel de novo variants and atypical presentation was noted in a patient. One variant turned out to be inherited from patient’s mother who had mosaic variant. Distinct phenotypes in patients with variant p.Glu246Lys and p.Arg209His were elucidated by in-depth phenotyping and literature review. Conclusions We reported 6 patients with GNAO1 encephalopathy showing an extremely diverse clinical spectrum on video. Some characteristic movement features identified by careful inspection may also provide important diagnostic insight and practice guidelines.

scholarly journals Spectrum of Movement Disorders in GNAO1 Encephalopathy: In-Depth Phenotyping and Case-by-Case Analysis

2020 ◽  
Author(s):  
Soo Yeon Kim ◽  
YoungKyu Shim ◽  
Young Joon Ko ◽  
Soojin Park ◽  
Se Song Jang ◽  
...  
Keyword(s):  
Literature Review ◽  
Exome Sequencing ◽  
Developmental Delay ◽  
Whole Exome Sequencing ◽  
De Novo ◽  
Neurodevelopmental Disorder ◽  
Epileptic Encephalopathy ◽  
Global Developmental Delay ◽  
Pathogenic Variants ◽  
Whole Exome

Abstract Background: GNAO1 encephalopathy is a rare neurodevelopmental disorder characterized by distinct movement presentations and early onset epileptic encephalopathy. Here, we report the in-depth phenotyping of genetically confirmed patients with GNAO1 encephalopathy, focusing on movement presentations.Results: Six patients who participated in Korean Undiagnosed Disease Program were diagnosed to have pathogenic or likely pathogenic variants in GNAO1 using whole exome sequencing. All medical records and personal video clips were analyzed with a literature review. Three of the 6 patients were male. Median follow-up duration was 41 months (range, 7–78 months) and age at last examination was 7.4 years (range, 3.3–16.9 years). Initial complaints were hypotonia or developmental delay in 5 and right-hand clumsiness in 1 patient, which were noticed at median age of 3 months (range, 0–75 months). All patients showed global developmental delay and 4 had severely retarded development. Five patients (5/6, 83.3%) had many different movement symptoms with various onset and progression. The symptoms included stereotyped hands movement, non-epileptic myoclonus, dyskinesia, dystonia and choreoathetosis. Whole exome sequencing identified 6 different variants in GNAO1. Three were novel de novo variants and atypical presentation was noted in a patient. One variant turned out to be inherited from patient’s mother who had mosaic variant. Distinct and characteristics movement phenotypes in patients with variant p.Glu246Lys and p.Arg209His were elucidated by in-depth phenotyping and literature review. Conclusions: We reported 6 patients with GNAO1 encephalopathy showing an extremely diverse clinical spectrum on video. Some characteristic movement features identified by careful inspection may also provide important diagnostic insight and practice guidelines.

scholarly journals Spectrum of movement disorders in GNAO1 encephalopathy: in-depth phenotyping and case-by-case analysis

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Soo Yeon Kim ◽  
YoungKyu Shim ◽  
Young Joon Ko ◽  
Soojin Park ◽  
Se Song Jang ◽  
...  
Keyword(s):  
Literature Review ◽  
Exome Sequencing ◽  
Developmental Delay ◽  
Whole Exome Sequencing ◽  
De Novo ◽  
Neurodevelopmental Disorder ◽  
Epileptic Encephalopathy ◽  
Global Developmental Delay ◽  
Pathogenic Variants ◽  
Whole Exome

Abstract Background GNAO1 encephalopathy is a rare neurodevelopmental disorder characterized by distinct movement presentations and early onset epileptic encephalopathy. Here, we report the in-depth phenotyping of genetically confirmed patients with GNAO1 encephalopathy, focusing on movement presentations. Results Six patients who participated in Korean Undiagnosed Disease Program were diagnosed to have pathogenic or likely pathogenic variants in GNAO1 using whole exome sequencing. All medical records and personal video clips were analyzed with a literature review. Three of the 6 patients were male. Median follow-up duration was 41 months (range 7–78 months) and age at last examination was 7.4 years (range 3.3–16.9 years). Initial complaints were hypotonia or developmental delay in 5 and right-hand clumsiness in 1 patient, which were noticed at median age of 3 months (range 0–75 months). All patients showed global developmental delay and 4 had severely retarded development. Five patients (5/6, 83.3%) had many different movement symptoms with various onset and progression. The symptoms included stereotyped hands movement, non-epileptic myoclonus, dyskinesia, dystonia and choreoathetosis. Whole exome sequencing identified 6 different variants in GNAO1. Three were novel de novo variants and atypical presentation was noted in a patient. One variant turned out to be inherited from patient’s mother who had mosaic variant. Distinct and characteristics movement phenotypes in patients with variant p.Glu246Lys and p.Arg209His were elucidated by in-depth phenotyping and literature review. Conclusions We reported 6 patients with GNAO1 encephalopathy showing an extremely diverse clinical spectrum on video. Some characteristic movement features identified by careful inspection may also provide important diagnostic insight and practice guidelines.

A De Novo Missense Variant in POU3F2 Identified in a Child with Global Developmental Delay

2018 ◽  
Vol 49 (06) ◽  
pp. 401-404 ◽  
Author(s):  
Korbinian Riedhammer ◽  
Reka Kovacs-Nagy ◽  
Thomas Meitinger ◽  
Julia Hoefele ◽  
Matias Wagner ◽  
...  
Keyword(s):  
Candidate Gene ◽  
Developmental Delay ◽  
Hormonal Regulation ◽  
De Novo ◽  
Missense Variant ◽  
Global Developmental Delay ◽  
Monogenic Disorders ◽  
Strong Candidate ◽  
The Brain ◽  
Generation Sequencing

Many genetic and nongenetic causes for developmental delay in childhood could be identified. Often, however, the molecular basis cannot be elucidated. As next-generation sequencing is becoming more frequently available in a diagnostic context, an increasing number of genetic variations are found as causative in children with developmental delay.We performed trio exome sequencing in a girl with developmental delay and minor dysmorphological features. Using a filter for de novo variants, the heterozygous missense variant c.812A>T, p.(Glu217Val) was found in the candidate gene POU3F2 in our patient. POU3F2 plays an important role in neuronal differentiation and hormonal regulation. To date, it has not been associated with monogenic disorders. Studies on Pou3f2 knockout mice highlighted the importance of this protein in the development of the brain. Furthermore, microdeletions with an overlapping region including only POU3F2 and FBXL4 were linked to developmental delay in six unrelated families. Therefore, POU3F2 is a strong candidate gene for developmental delay, although functional assays proving this assumption still have to be done.

A novel de novo TMEM63A variant in a patient with severe hypomyelination and global developmental delay

2021 ◽  
Author(s):  
Shinobu Fukumura ◽  
Takuya Hiraide ◽  
Akiyo Yamamoto ◽  
Kousuke Tsuchida ◽  
Kazushi Aoto ◽  
...  
Keyword(s):  
Developmental Delay ◽  
De Novo ◽  
Global Developmental Delay

scholarly journals A Novel Heterozygous Missense Variant in YWHAG Gene Cause Early-Onset Epilepsy in a Chinese Family

2020 ◽  
Author(s):  
Zhi Yi ◽  
Zhenfeng Song ◽  
Jiao Xue ◽  
Chengqing Yang ◽  
Fei Li ◽  
...  
Keyword(s):  
Early Onset ◽  
Seizure Control ◽  
De Novo ◽  
Missense Variant ◽  
Epileptic Encephalopathy ◽  
Chinese Family ◽  
Gene Variants ◽  
Case Presentation ◽  
Epileptic Encephalopathies ◽  
Refractory Seizures

Abstract Background: Developmental and epileptic encephalopathies (DEE) are a heterogeneous group of severe disorders which are characterized by early-onset, refractory seizures and developmental slowing or regression. Genetic variations are significant causes for them. De novo variants in an increasing number of candidate genes have been found to be causal. YWHAG gene variants have been reported to cause developmental and epileptic encephalopathy 56 (DEE56). Case presentation: Here, we report a novel heterozygous missense variant c.170G>A (p.R57H) in YWHAG gene cause early-onset epilepsy in a Chinese family. Both the proband and his mother exhibit early onset seizures, intellectual disability, developmental delay. While the proband achieve seizure control with sodium valproate, his mother's seizures were not well controlled. Conclusions: Our report further confirming the haploinsufficiency of YWHAG results in developmental and epileptic encephalopathies.

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