scholarly journals A Japanese boy with double diagnoses of 2p15p16.1 microdeletion syndrome and RP2-associated retinal disorder

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Kazuki Yamazawa ◽  
Kenji Shimizu ◽  
Hirofumi Ohashi ◽  
Hidenori Haruna ◽  
Satomi Inoue ◽  
...  
Keyword(s):  
Developmental Delay ◽  
Retinal Disease ◽  
Recurrence Risk ◽  
Therapeutic Options ◽  
Loss Of Function ◽  
Childhood Onset ◽  
Microdeletion Syndrome ◽  
Dysmorphic Features ◽  
Inherited Retinal Disease ◽  
Retinal Disorder

Abstract2p15p16.1 microdeletion syndrome is a recently recognized congenital disorder characterized by developmental delay and dysmorphic features. RP2-associated retinal disorder (RP2-RD) is an X-linked inherited retinal disease with a childhood onset caused by a loss-of-function variant in the RP2 gene. Here, we describe a 14-year-old boy with double diagnoses of 2p15p16.1 microdeletion syndrome and RP2-RD. The recurrence risk of each condition and the indication for potential therapeutic options for RP2-RD are discussed.

scholarly journals Paternal Uniparental Isodisomy of Chromosome 2 in a Patient with CNGA3-Associated Autosomal Recessive Achromatopsia

2021 ◽  
Vol 22 (15) ◽  
pp. 7842
Author(s):  
Susanne Kohl ◽  
Britta Baumann ◽  
Francesca Dassie ◽  
Anja K. Mayer ◽  
Maria Solaki ◽  
...  
Keyword(s):  
Segregation Analysis ◽  
Molecular Genetic ◽  
Retinal Disease ◽  
Underlying Mechanism ◽  
Recurrence Risk ◽  
Molecular Genetic Analysis ◽  
Recessive Mutation ◽  
Chromosome 2 ◽  
Inherited Retinal Disease ◽  
Uniparental Isodisomy

Achromatopsia (ACHM) is a rare autosomal recessively inherited retinal disease characterized by congenital photophobia, nystagmus, low visual acuity, and absence of color vision. ACHM is genetically heterogeneous and can be caused by biallelic mutations in the genes CNGA3, CNGB3, GNAT2, PDE6C, PDE6H, or ATF6. We undertook molecular genetic analysis in a single female patient with a clinical diagnosis of ACHM and identified the homozygous variant c.778G>C;p.(D260H) in the CNGA3 gene. While segregation analysis in the father, as expected, identified the CNGA3 variant in a heterozygous state, it could not be displayed in the mother. Microsatellite marker analysis provided evidence that the homozygosity of the CNGA3 variant is due to partial or complete paternal uniparental isodisomy (UPD) of chromosome 2 in the patient. Apart from the ACHM phenotype, the patient was clinically unsuspicious and healthy. This is one of few examples proving UPD as the underlying mechanism for the clinical manifestation of a recessive mutation in a patient with inherited retinal disease. It also highlights the importance of segregation analysis in both parents of a given patient or especially in cases of homozygous recessive mutations, as UPD has significant implications for genetic counseling with a very low recurrence risk assessment in such families.

scholarly journals Interstitial deletion of 6q25.2–q25.3: a novel microdeletion syndrome associated with microcephaly, developmental delay, dysmorphic features and hearing loss

2008 ◽  
Vol 17 (5) ◽  
pp. 573-581 ◽  
Author(s):  
Sandesh Chakravarthy Sreenath Nagamani ◽  
Ayelet Erez ◽  
Christine Eng ◽  
Zhishuo Ou ◽  
Craig Chinault ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Developmental Delay ◽  
Interstitial Deletion ◽  
Microdeletion Syndrome ◽  
Dysmorphic Features

scholarly journals Rare GABRA3 variants are associated with epileptic seizures, encephalopathy and dysmorphic features

Brain ◽  
2017 ◽  
Vol 140 (11) ◽  
pp. 2879-2894 ◽  
Author(s):  
Cristina Elena Niturad ◽  
Dorit Lev ◽  
Vera M Kalscheuer ◽  
Agnieszka Charzewska ◽  
Julian Schubert ◽  
...  
Keyword(s):  
Intellectual Disability ◽  
Developmental Delay ◽  
Gabaa Receptor ◽  
Xenopus Laevis Oocytes ◽  
Incomplete Penetrance ◽  
Single Mutation ◽  
Loss Of Function ◽  
Missense Variants ◽  
Dysmorphic Features ◽  
Α3 Subunit

Abstract Genetic epilepsies are caused by mutations in a range of different genes, many of them encoding ion channels, receptors or transporters. While the number of detected variants and genes increased dramatically in the recent years, pleiotropic effects have also been recognized, revealing that clinical syndromes with various degrees of severity arise from a single gene, a single mutation, or from different mutations showing similar functional defects. Accordingly, several genes coding for GABAA receptor subunits have been linked to a spectrum of benign to severe epileptic disorders and it was shown that a loss of function presents the major correlated pathomechanism. Here, we identified six variants in GABRA3 encoding the α3-subunit of the GABAA receptor. This gene is located on chromosome Xq28 and has not been previously associated with human disease. Five missense variants and one microduplication were detected in four families and two sporadic cases presenting with a range of epileptic seizure types, a varying degree of intellectual disability and developmental delay, sometimes with dysmorphic features or nystagmus. The variants co-segregated mostly but not completely with the phenotype in the families, indicating in some cases incomplete penetrance, involvement of other genes, or presence of phenocopies. Overall, males were more severely affected and there were three asymptomatic female mutation carriers compared to only one male without a clinical phenotype. X-chromosome inactivation studies could not explain the phenotypic variability in females. Three detected missense variants are localized in the extracellular GABA-binding NH2-terminus, one in the M2-M3 linker and one in the M4 transmembrane segment of the α3-subunit. Functional studies in Xenopus laevis oocytes revealed a variable but significant reduction of GABA-evoked anion currents for all mutants compared to wild-type receptors. The degree of current reduction correlated partially with the phenotype. The microduplication disrupted GABRA3 expression in fibroblasts of the affected patient. In summary, our results reveal that rare loss-of-function variants in GABRA3 increase the risk for a varying combination of epilepsy, intellectual disability/developmental delay and dysmorphic features, presenting in some pedigrees with an X-linked inheritance pattern. 10.1093/brain/awx236_video1 awx236media1 5636589232001

scholarly journals A recurrent, homozygous EMC10 frameshift variant is associated with a syndrome of developmental delay with variable seizures and dysmorphic features

2021 ◽  
Author(s):  
Diane D. Shao ◽  
Rachel Straussberg ◽  
Hind Ahmed ◽  
Amjad Khan ◽  
Songhai Tian ◽  
...  
Keyword(s):  
Developmental Delay ◽  
Global Developmental Delay ◽  
Endoplasmic Reticulum Membrane ◽  
Loss Of Function ◽  
Human Brain Tissue ◽  
Dysmorphic Features ◽  
Membrane Complex ◽  
Normal Human ◽  
Curly Hair ◽  
Neurodevelopmental Phenotype

Abstract Purpose The endoplasmic reticulum membrane complex (EMC) is a highly conserved, multifunctional 10-protein complex related to membrane protein biology. In seven families, we identified 13 individuals with highly overlapping phenotypes who harbor a single identical homozygous frameshift variant in EMC10. Methods Using exome, genome, and Sanger sequencing, a recurrent frameshift EMC10 variant was identified in affected individuals in an international cohort of consanguineous families. Multiple families were independently identified and connected via Matchmaker Exchange and internal databases. We assessed the effect of the frameshift variant on EMC10 RNA and protein expression and evaluated EMC10 expression in normal human brain tissue using immunohistochemistry. Results A homozygous variant EMC10 c.287delG (Refseq NM_206538.3, p.Gly96Alafs*9) segregated with affected individuals in each family, who exhibited a phenotypic spectrum of intellectual disability (ID) and global developmental delay (GDD), variable seizures and variable dysmorphic features (elongated face, curly hair, cubitus valgus, and arachnodactyly). The variant arose on two founder haplotypes and results in significantly reduced EMC10 RNA expression and an unstable truncated EMC10 protein. Conclusion We propose that a homozygous loss-of-function variant in EMC10 causes a novel syndromic neurodevelopmental phenotype. Remarkably, the recurrent variant is likely the result of a hypermutable site and arose on distinct founder haplotypes.

scholarly journals A qualitative study among patients with an inherited retinal disease on the meaning of genomic unsolicited findings

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Marlies Saelaert ◽  
Heidi Mertes ◽  
Tania Moerenhout ◽  
Caroline Van Cauwenbergh ◽  
Bart P. Leroy ◽  
...  
Keyword(s):  
Qualitative Study ◽  
Interpretative Phenomenological Analysis ◽  
Age Of Onset ◽  
Genetic Diseases ◽  
Retinal Disease ◽  
Clinical Approach ◽  
Inherited Retinal Disease ◽  
Illness Experiences ◽  
Meaning Structure ◽  
Main Components

AbstractExome-based testing for genetic diseases can reveal unsolicited findings (UFs), i.e. predispositions for diseases that exceed the diagnostic question. Knowledge of patients’ interpretation of possible UFs and of motives for (not) wanting to know UFs is still limited. This lacking knowledge may impede effective counselling that meets patients’ needs. Therefore, this article examines the meaning of UFs from a patient perspective. A qualitative study was conducted and an interpretative phenomenological analysis was made of 14 interviews with patients with an inherited retinal disease. Patients assign a complex meaning to UFs, including three main components. The first component focuses on result-specific qualities, i.e. the characteristics of an UF (inclusive of actionability, penetrance, severity and age of onset) and the consequences of disclosure; the second component applies to a patient’s lived illness experiences and to the way these contrast with reflections on presymptomatic UFs; the third component addresses a patient’s family embedding and its effect on concerns about disease prognosis and genetic information’s family relevance. The complex meaning structure of UFs suggests the need for counselling procedures that transcend a strictly clinical approach. Counselling should be personalised and consider patients’ lived illness experiences and family context.

scholarly journals The de novo CACNA1A pathogenic variant Y1384C associated with hemiplegic migraine, early onset cerebellar atrophy and developmental delay leads to a loss of Cav2.1 channel function

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Maria A. Gandini ◽  
Ivana A. Souza ◽  
Laurent Ferron ◽  
A. Micheil Innes ◽  
Gerald W. Zamponi
Keyword(s):  
Developmental Delay ◽  
Early Onset ◽  
Structural Damage ◽  
De Novo ◽  
Splice Variants ◽  
Cerebellar Atrophy ◽  
Familial Hemiplegic Migraine ◽  
Significant Loss ◽  
Loss Of Function ◽  
Hemiplegic Migraine

AbstractCACNA1A pathogenic variants have been linked to several neurological disorders including familial hemiplegic migraine and cerebellar conditions. More recently, de novo variants have been associated with severe early onset developmental encephalopathies. CACNA1A is highly expressed in the central nervous system and encodes the pore-forming CaVα1 subunit of P/Q-type (Cav2.1) calcium channels. We have previously identified a patient with a de novo missense mutation in CACNA1A (p.Y1384C), characterized by hemiplegic migraine, cerebellar atrophy and developmental delay. The mutation is located at the transmembrane S5 segment of the third domain. Functional analysis in two predominant splice variants of the neuronal Cav2.1 channel showed a significant loss of function in current density and changes in gating properties. Moreover, Y1384 variants exhibit differential splice variant-specific effects on recovery from inactivation. Finally, structural analysis revealed structural damage caused by the tyrosine substitution and changes in electrostatic potentials.

Sleep Exacerbations and Facial Twitching: Diagnostic Clues for ADCY5-Related Dyskinesias

2020 ◽  
Author(s):  
Margherita Nosadini ◽  
Gianluca D'Onofrio ◽  
Maria Federica Pelizza ◽  
Concetta Luisi ◽  
Davide Padrin ◽  
...  
Keyword(s):  
Movement Disorder ◽  
Developmental Delay ◽  
De Novo ◽  
Brain Magnetic Resonance Imaging ◽  
Neurological Impairment ◽  
De Novo Mutation ◽  
Oligoclonal Bands ◽  
Emotional Stimuli ◽  
Childhood Onset ◽  
Ataxic Gait

Abstract Background Mutations in the adenylate cyclase 5 (ADCY5) gene are associated with childhood-onset paroxysmal dyskinesia. Methods We report a new video-documented case of pediatric ADCY5-related dyskinesia with de novo ADCY5 mutation. Results A boy born to nonconsanguineous parents after an uneventful pregnancy had developmental delay and hypotonia. At the age of 7 months, he presented with paroxysmal jerky–choreic–dystonic involuntary movements in wakefulness involving limbs, trunk, and face, exacerbated by emotional stimuli. These episodes gradually worsened in duration and frequency: at the age of 2.5 years, they occurred up to six times per day, and appeared also during sleep in prolonged bouts; the boy also had basal choreoathetoid–dystonic movements, hyperactivity, paraparetic–ataxic gait, generalized hypotonia with brisk tendon reflexes, drooling, and language delay with intellectual disability. Brain magnetic resonance imaging, electroencephalogram, electromyogram, eye review, metabolic investigations, oligoclonal bands, and autoantibodies were normal. Extensive genetic testing had not let to a diagnosis, until a heterozygous de novo mutation c.1252C > T (p.Arg418Trp) was identified in the ADCY5 gene. Clonazepam had partial effectiveness. The boy walked at the age of 3.5 years. At the age of 5 years, the paroxysmal movement disorder has slightly improved. Conclusion ADCY5 mutations should be considered among the differential diagnoses of early-onset paroxysmal choreic–athetosic–myoclonic–dystonic movement disorder involving limbs, trunk, and face, in patients with global neurological impairment with hypotonia and developmental delay. Facial dyskinesias and exacerbation by drowsiness/sleep and emotional stimuli are important clues that may allow a timely recognition of the disorder and avoidance of unnecessary diagnostic investigations.

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