ABSTRACT
OBJECTIVE: Pathogenic SLC6A1 variants were recently described in patients with myoclonic atonic epilepsy (MAE) and intellectual disability (ID). We set out to define the phenotypic spectrum in a larger cohort of SCL6A1-mutated patients. METHODS: We collected 24 SLC6A1 probands and 6 affected family members. Four previously published cases were included for further electroclinical description. In total, we reviewed the electroclinical data of 34 subjects. RESULTS: Cognitive development was impaired in 33/34 (97%) subjects; 28/34 had mild to moderate ID, with language impairment being the most common feature. Epilepsy was diagnosed in 31/34 cases with mean onset at 3.7 years. Cognitive assessment before epilepsy onset was available in 24/31 subjects and was normal in 25% (6/24), and consistent with mild ID in 46% (11/24) or moderate ID in 17% (4/24). Two patients had speech delay only, and 1 had severe ID. After epilepsy onset, cognition deteriorated in 46% (11/24) of cases. The most common seizure types were absence, myoclonic, and atonic seizures. Sixteen cases fulfilled the diagnostic criteria for MAE. Seven further patients had different forms of generalized epilepsy and 2 had focal epilepsy. Twenty of 31 patients became seizure-free, with valproic acid being the most effective drug. There was no clear-cut correlation between seizure control and cognitive outcome. Electroencephalography (EEG) findings were available in 27/31 patients showing irregular bursts of diffuse 2.5-3.5 Hz spikes/polyspikes-and-slow waves in 25/31. Two patients developed an EEG pattern resembling electrical status epilepticus during sleep. Ataxia was observed in 7/34 cases. We describe 7 truncating and 18 missense variants, including 4 recurrent variants (Gly232Val, Ala288Val, Val342Met, and Gly362Arg). SIGNIFICANCE: Most patients carrying pathogenic SLC6A1 variants have an MAE phenotype with language delay and mild/moderate ID before epilepsy onset. However, ID alone or associated with focal epilepsy can also be observed.
Subject(s)
Epilepsies, Myoclonic/physiopathology , GABA Plasma Membrane Transport Proteins/genetics , Intellectual Disability/physiopathology , Language Development Disorders/physiopathology , Adolescent , Adult , Anticonvulsants/therapeutic use , Ataxia/complications , Ataxia/genetics , Ataxia/physiopathology , Child , Child, Preschool , Cohort Studies , Electroencephalography , Epilepsies, Myoclonic/complications , Epilepsies, Myoclonic/drug therapy , Epilepsies, Myoclonic/genetics , Epilepsies, Partial/complications , Epilepsies, Partial/drug therapy , Epilepsies, Partial/genetics , Epilepsies, Partial/physiopathology , Epilepsy, Generalized/complications , Epilepsy, Generalized/drug therapy , Epilepsy, Generalized/genetics , Epilepsy, Generalized/physiopathology , Female , Genetic Association Studies , Humans , Intellectual Disability/complications , Intellectual Disability/genetics , Language Development Disorders/complications , Language Development Disorders/genetics , Male , Mutation , Mutation, Missense , Neurodevelopmental Disorders/complications , Neurodevelopmental Disorders/genetics , Phenotype , Treatment Outcome , Valproic Acid/therapeutic use , Young AdultABSTRACT
Low-copy repeats (LCRs) are genomic features that affect chromosome stability and can produce disease-associated rearrangements. We describe members of three families with deletions in 10q22.3-q23.31, a region harboring a complex set of LCRs, and demonstrate that rearrangements in this region are associated with behavioral and neurodevelopmental abnormalities, including cognitive impairment, autism, hyperactivity, and possibly psychiatric disease. Fine mapping of the deletions in members of all three families by use of a custom 10q oligonucleotide array-based comparative genomic hybridization (NimbleGen) and polymerase chain reaction-based methods demonstrated a different deletion in each family. In one proband, the deletion breakpoints are associated with DNA fragments containing noncontiguous sequences of chromosome 10, whereas, in the other two families, the breakpoints are within paralogous LCRs, removing approximately 7.2 Mb and 32 genes. Our data provide evidence that the 10q22-q23 genomic region harbors one or more genes important for cognitive and behavioral development and that recurrent deletions affecting this interval define a novel genomic disorder.
Subject(s)
Child Behavior Disorders/genetics , Chromosome Deletion , Chromosomes, Human, Pair 10/genetics , Cognition Disorders/genetics , Autistic Disorder/genetics , Child , Child, Preschool , Chromosome Banding , Chromosome Breakage , Chromosome Mapping , Chromosomes, Artificial, Bacterial/genetics , Female , Gene Rearrangement , Humans , In Situ Hybridization, Fluorescence , Infant , Male , Models, Genetic , Oligonucleotide Array Sequence Analysis , Pedigree , Repetitive Sequences, Nucleic AcidABSTRACT
Idiopathic intracranial hypertension, characterized by headache, visual disturbance, papilledema, and increased intracranial pressure in the absence of space-occupying lesions, has been reported in pediatric recipients several months to years following kidney transplantation (KTx). We describe the development of idiopathic intracranial hypertension in a 10-year-old girl in the first few hours after KTx. We hypothesize that this event was associated with thymoglobulin administration, perhaps on the background of growth hormone therapy. Awareness of this possibility could lead to earlier diagnosis and treatment of children with similar risk factors.
