A new locus for autosomal dominant generalized epilepsy associated with mild mental retardation on chromosome 3p

Purpose: Generalized epilepsies are clinically and genetically heterogeneous syndromes. Idiopathic generalized epilepsy (IGE), which has a strong genetic background, is not associated with any additional clinical features, such as mental retardation (MR). Herein we report results of linkage analysis in a large family with autosomal dominant (AD) generalized epilepsy associated with MR. Methods: We identified a four‐generation kindred with several affected members with generalized epilepsy without any evidence for secondary causes. Electroencephalography (EEG) studies and magnetic resonance imaging (MRI) results were reviewed when available. We performed a genome‐wide linkage analysis. Key Findings: Fourteen individuals were classified as affected and an additional three were considered as nonpenetrant obligatory carriers. Thirteen affected individual had a history of generalized tonic–clonic seizures, and absence seizures were reported in nine affected individuals. There was no history of preceding febrile seizures. MR was present in nine affected individuals with epilepsy but the other affected individuals had normal intelligence. Neuroimaging did not reveal any structural abnormalities and EEG studies were consistent with IGE rather than symptomatic generalized epilepsy. Genetic analysis detected a group of markers with logarithmic (base 10) of odds (LOD) score >3 on chromosome 3p spanning a 5.5 Mbp region. Sequencing of several candidate genes, including dynein light chain‐A, golgin subfamily a4, leucine rich repeat (in FLII) interacting gene, serine/threonine‐protein kinase DCAMKL3 (doublecortin‐ like and CAM kinase‐like 3), laforin (EPM2A) interacting protein 1 (EPM2AIP1, programmed cell death 6 interacting protein, and CLIP‐associating protein 2 (cytoplasmic linker‐associated protein 2) (hOrbit2) genes did not identify the disease‐causing mutations. Significance: We report the identification of a genetic locus for generalized epilepsy associated with MR on chromosome 3p. Affected individuals have a form of genetic epilepsy with generalized seizures variably associated with MR. Despite the presence of MR in several affected patients, epilepsy phenotype was not fully consistent with symptomatic epilepsy and suggests a biologic continuum between symptomatic epilepsies and IGE.     

Usefulness of a simple sleep-deprived EEG protocol for epilepsy diagnosis in de novo subjects

Objective

In case series concerning the role of EEG after sleep deprivation (SD-EEG) in epilepsy, patients’ features and protocols vary dramatically from one report to another. In this study, we assessed the usefulness of a simple SD-EEG method in well characterized patients.

Methods

Among the 963 adult subjects submitted to SD-EEG at our Center, in the period 2003–2010, we retrospectively selected for analysis only those: (1) evaluated for suspected epileptic seizures; (2) with a normal/non-specific baseline EEG; (3) still drug-free at the time of SD-EEG; (4) with an MRI analysis; (5) with at least 1 year follow-up. SD-EEG consisted in SD from 2:00 AM and laboratory EEG from 8:00 AM to 10:30 AM. We analyzed epileptic interictal abnormalities (IIAs) and their correlations with patients’ features.

Results

Epilepsy was confirmed in 131 patients. SD-EEG showed IIAs in 41.2% of all patients with epilepsy, and a 91.1% specificity for epilepsy diagnosis; IIAs types observed during SD-EEG are different in generalized versus focal epilepsies; for focal epilepsies, the IIAs yield in SD-EEG is higher than in second routine EEG.

Conclusions

This simple SD-EEG protocol is very useful in de novo patients with suspected seizures.

Significance

This study sheds new light on the role of SD-EEG in specific epilepsy populations.     

A new syndrome of mental retardation and epilepsy characterized by dense microsphere accumulation

Summary Dense microspheres (DMS) are enigmatic structures found within dendrites in the normal human cortex; their composition and function are unknown. We describe a case of a 29-year-old male with a history of mental retardation and epilepsy in whom the unique neuropathological finding was a marked excess of DMS, most notably in the neocortex. This is a previously undescribed neuropathological syndrome, and represents the first unequivocal association of DMS with a neurological disorder.     

Levetiracetam for people with mental retardation and refractory epilepsy

Levetiracetam (LEV) is a novel antiepileptic drug (AED) with efficacy against a wide range of seizures types. The aim of this observational study was to assess its effectiveness in patients with mental retardation and refractory epilepsy. Sixty-four patients were started on adjunctive LEV after a 3-month baseline. LEV was initially dosed at 250 mg daily and increased by 250 mg every 2 weeks thereafter according to clinical response. Caregivers rated the patient's sleep, appetite, alertness, and behavior as poor (1), reasonable (2), or good (3) at each clinic visit. Patients were reviewed until one of four endpoints was reached: seizure freedom for at least 6 months, > or = 50% reduction in seizure frequency (responder) over a 6-month period, <50% reduction in seizure frequency (marginal effect) over a 6-month period, or LEV withdrawal due to lack of efficacy, adverse effects, or both. Twenty-four (38%) patients became seizure-free, 10 of whom were controlled on LEV 250 mg twice daily. An additional 18 (28%) patients were classified as responders, and 8 (12%) reported only marginal benefit from adjunctive LEV. Fourteen (22%) patients discontinued LEV (6 worsening seizures, 1 lack of efficacy, 7 adverse effects). Caregivers rated combined sleep, appetite, alertness, and behavior scores as "improved" at the end of follow-up (P<0.001). LEV improved seizure control in the majority of patients with mental retardation and may also have enhanced their quality of life.     

Partial monosomy Xq(Xq23 --> qter) and trisomy 4p(4p15.33 --> pter) in a woman with intractable focal epilepsy, borderline intellectual functioning, and dysmorphic features

Studies of epilepsy associated with chromosomal abnormalities may provide information about clinical and EEG phenotypes and possibly to identify new epilepsy genes. We describe a female patient with intractable focal epilepsy, borderline intellectual functioning, and facial dysmorphisms, in whom genetic study (i.e., karyotype and array-CGH analysis) revealed a distal trisomy 4p and distal monosomy Xq. Although any genetic hypothesis remains speculative, several genes are located in the 4p chromosome segment involved in the rearrangement, some of which may be related to epilepsy.     

Facioscapulohumeral muscular dystrophy with severe mental retardation and epilepsy

We report here a case of a 20-year-old woman with facioscapulohumeral muscular dystrophy (FSHD). In this patient, the involvement of facial muscle had been present since early childhood, but obscured due to the complication of profound mental retardation. Epilepsy emerged at eight years of age. Symmetrical limb muscle weakness appeared at 15 years of age, which progressed such that she was wheelchair-bound at 18 years of age. An elevated serum creatine kinase, predominant involvement of hamstrings, scapular and abdominal muscles, as well as an impaired stapedial reflex at high tune, were compatible with the clinical features of FSHD. The diagnosis of 4q35-FSHD was confirmed by detection of a 10kb EcoRI fragment with a p13E-11 probe on a Southern blot. The intellectual disability in this patient was the most severe of all FSHD patients reported to date and has hindered a correct diagnosis. This entity should be included in the differential diagnoses for patients with muscular symptoms and accompanying mental retardation.     

Development and validation of the Glasgow Epilepsy Outcome Scale (GEOS): a new instrument for measuring concerns about epilepsy in people with mental retardation

PURPOSE: To develop a measure for use with adults with epilepsy and mental retardation, capable of assessing both clinical and care concerns and of quantifying treatment outcomes. METHODS: Extensive validational and other psychometric evaluation was undertaken, comprising initial scale development work with 48 carers and 46 health practitioners, followed by formal field testing on a sample of 186 patients, using 384 respondents (160 clinicians, 141 staff, 83 family). Recognised qualitative methods were applied to identify central themes, and psychometric procedures generated data on validity, reliability, and component structure. RESULTS: A total of 1,007 items of concern was generated, which was reduced systematically to a representative set of 90 items. The GEOS-90 comprises four subscales: concerns about "seizures," "treatment," "caring," and "social impact," each explaining approximately 70% of variance. Subscales and factor scales had strong internal consistency (alpha > or = 0.82). Stepwise linear regression was applied to derive a short-form version with similar structure. Thirty-five items were retained (GEOS-35; alpha > or = 0.89). Both scales discriminated moderately on clinical variables (number of seizure types, mono- vs. polytherapy, seizure frequency; all values of p < 0.05) and demonstrated concurrent validity with interview ratings from the ELDQOL (p < 0.05). CONCLUSIONS: The GEOS scales appear valid and reliable for use with clinical populations of people with mental retardation.     

Novel AGTR2 missense mutation in a Japanese boy with severe mental retardation, pervasive developmental disorder, and epilepsy

Angiotensin II type-2 receptor gene (AGTR2) mutations have been recently detected in patients with mental retardation. AGTR2 plays a role in central nervous system development and cognitive functions. We identified a novel missense mutation of c.572G>A (p.G191E) in a 6-year-old boy showing severe mental retardation, pervasive developmental disorder, and epilepsy. This is the first report on AGTR2 mutation in a Japanese boy with mental retardation.     

Balanced translocation in a patient with severe myoclonic epilepsy of infancy disrupts the sodium channel gene SCN1A

In a patient with severe myoclonic epilepsy of infancy (SMEI), we identified a de novo balanced translocation, t(2;5)(q24.3,q34). The breakpoint on chromosome 2q24.3 truncated the SCN1A gene and the 5q34 breakpoint was within a highly conserved genomic region. Point mutations or microdeletions of SCN1A have previously been identified in SMEI patients, but this is the first report of a balanced translocation disrupting the SCN1A gene in an epilepsy patient. We therefore recommend that SMEI patients without SCN1A microdeletions or point mutations should be investigated for chromosomal rearrangements.     

Epilepsy and the impact of an epileptology clinic for patients with mental retardation and associated disabilities in an institutional setting

Summary:  Purpose: Epilepsy is a common problem in institutionalized patients with multiple handicaps. Limited data exist on the characteristics of epilepsy in this patient population and the impact of systematic evaluation by an epilepsy service.
Methods: We evaluated 138 patients with epilepsy, institutionalized at a facility that cares for 324 patients with multiple handicaps. Evaluation included EEG, MRI, and video-EEG monitoring. The medication regimen was changed according to seizure diagnosis and the status of seizure control. Follow-up was available for ≥6 months in 110 patients, 1 year for 89, and 1.5 years for 49 patients. We analyzed the seizure and epilepsy diagnosis in this population, as well as the seizure frequency after evaluation and treatment
Results: The 76 male and 62 female patients' ages ranged from 14 to 73 years. Seventy-three patients had fewer than one seizure per month, whereas 29 patients had at least one seizure per month. Of 131 patients taking antiepileptic drugs (AEDs), 62 were receiving monotherapy, and 69 were receiving two or more AEDs. At the last follow-up, overall 55% of patients had reduced seizure frequency, including 23% who became seizure free. Two of 36 patients had spontaneous seizure recurrence after being seizure free with no AEDs for 4 months in one patient and 3 years for the other. Attempts were made to discontinue phenobarbital, primidone, and clonazepam in 21 patients. However, these were discontinued in only five patients.
Conclusions: Epilepsy is heterogeneous in institutionalized patients with multiple handicaps. It is often responsive to medical therapy. Evaluation and treatment by epilepsy specialists had an overall favorable impact on seizure control.     

12P部分三体的细胞-分子遗传学及表型定位研究

目的 进一步探讨12p部分三体综合征遗传物质增加与临床表现之间的关系.方法 我们对1例具有发育缓慢、精神发育迟滞和面部畸形的13个月大患儿和双亲进行了包括G显带、高分辨和荧光原位杂交(fluorescence in situ hybridization,:FISH)分析,同时对包括文献报道的24例12p部分三体进行表型定位分析.结果 患者的12p部分三体来源于母亲的平衡易位,小睑的发生可能与剂量关系不大,而是12p13区域存在与眼睑发育有关的基因簇,染色体断裂后直接或者间接的影响了他们的表达或功能.导致眼睑发育异常.结论 12p部分三体的典型症状与特定染色体区域的基因表达或功能有关.     

Depression,anxiety, and relevant cognitions in persons with mental retardation

We assessed depression, anxiety, and relevant cognitions in persons with mental retardation by administering modified versions of the Reynolds Child Depression Scale, the Beck Anxiety Inventory, the Automatic Thoughts Questionnaire, and the Cognitions Checklist to 46 persons with borderline to moderate mental retardation. Consistent with research with other groups, self-reports of depression and anxiety were highly correlated (r = .74) in these individuals, and cognitions were strong predictors of negative affect. Subscales measuring cognitions related to depression and anxiety were also highly related, limiting the cognitive-specificity hypothesis. Hierarchical multiple regression analyses offered mixed support for cognitive-specificity. We discuss the implications of these findings for the cognitive and affective assessment of persons with intellectual limitations.     

Case report: autistic disorder and chromosomal abnormality 46, XX duplication (4) p12-p13

 We report an 18-year-old female with a diagnosis of DSM-IV Autistic Disorder and moderate to severe mental retardation who was discovered to have a previously undescribed chromosomal abnormality 46, XX, duplication (4) p12–p13. We discuss her history and diagnosis, noting that the co-occurrence of her diagnoses have not previously been documented. The report adds to the literature supporting the argument that individuals with autistic spectrum disorders should be re-examined for chromosomal abnormalities. Accepted: 17 April 2000     

Outcome after corpus callosotomy in children with injurious drop attacks and severe mental retardation

Wide variability in patient selection, extent of callosal section and definition of successful outcome between studies make impact of corpus callosotomy on patients with medically refractory epilepsies difficult to interpret. Severe mental retardation is considered to be predictive of unfavorable seizure outcome after callosotomy. Very little attention has been paid on the influence of callosotomy on the psychosocial burden on the patients' families. We evaluated the seizure outcome, and parental perception about change in cognition and behavior of 17 children (median age 9.5 years, range 3.5-18 years) with severe mental retardation (IQ<30 in all, except one) and injurious drop attacks, who have completed >or=1-year postoperative follow-up after callosotomy. Nearly two-thirds of our patients had >or=90% reduction in drop attacks and generalized tonic-clonic seizures. In the one-stage total callosotomy group, 9 of 11 (82%) patients had favorable outcome, compared to 2 of the 6 (33%) in the partial callosotomy group. Absence of generalized epileptiform discharges on the 1-year postoperative EEG was significantly associated with a favorable seizure outcome. The mean duration of epilepsy prior to callosotomy tended to be shorter among patients with favorable seizure outcome. Postoperative complications were trivial and transient. Nearly three-fourths of the parents appreciated improvements in behavior and attentiveness of their children and were satisfied with the outcome. We conclude that, in children with severe mental retardation and injurious drop attacks, total callosotomy can be undertaken as a one-stage procedure with insignificant morbidity and results in highly favorable seizure outcome.     

Correlation between dental maturation and chronological age in patients with cerebral palsy, mental retardation, and Down syndrome

Determining a child's chronological age and stage of maturation is particularly important in fields such as paediatrics, orthopaedics, and orthodontics, as well as in forensic and anthropological studies. Some systemic conditions can cause abnormal physiological maturation, and skeletal maturation is usually more delayed than dental maturation. The aim of this study was to determine dental age in a group of patients with the most prevalent congenital or perinatally occurring physical and mental disabilities. The study group comprised 155 white Spanish children aged 3-17 years (35 with cerebral palsy, 83 with mental retardation and no associated syndromes or systemic conditions, and 37 with Down syndrome). The dental maturation indices described by Nolla and Demirjian were used to generate regression lines for the dental age of individuals in a control group (688 white Spanish children aged 3-17 years) and the formulae were then used to determine the dental age of patients in the study group. No significant differences were found between dental and chronological age in boys with cerebral palsy, mental retardation, or Down syndrome. In contrast, dental age (calculated from the linear regression model that included values for the Demirjian index) was significantly delayed compared with chronological age in girls with cerebral palsy or Down syndrome.     

Homozygous c.649dupC mutation in PRRT2 worsens the BFIS/PKD phenotype with mental retardation,episodic ataxia,and absences

Heterozygous mutations of PRRT2, which encodes proline‐rich transmembrane protein 2, are associated with heterogeneous phenotypes including benign familial infantile seizures (BFIS), or familial paroxysmal kinesigenic dystonia (PKD). We report a consanguineous Italian family with BFIS/PKD phenotype that contained 14 living members with 6 affected individuals (four men, ranging in age from 6–44 years). We identified the reported c.649dupC (p.Arg217ProfsX8) mutation of PRRT2 gene that cosegregated with the disease and was not observed in 100 controls of matched ancestry. Four patients with BFIS phenotype were heterozygous for this mutation, including the consanguineous parents of the two affected brothers with more severe phenotypes of BFIS/PKD—mental retardation, episodic ataxia, and absences—who were the only individuals to carry a homozygous c.649dupC mutation. This family provides strong evidence that homozygous PRRT2 mutations give rise to more severe clinical disease of mental retardation, episodic ataxia, and absences, and, thus, enlarges the clinical spectrum related to PRRT2 mutations. Moreover, it suggests an additive effect of double dose of the genetic mutation and underscores the complexity of the phenotypic consequences of mutations in this gene.     

Urine screening for patients with developmental disabilities detected a patient with creatine transporter deficiency due to a novel missense mutation in SLC6A8

Creatine transporter deficiency (CTD) is an example of X-linked intellectual disability syndromes, caused by mutations in SLC6A8 on Xq28. Although this is the second most frequent genetic cause of intellectual disabilities in Europe or America after Fragile X syndrome, information on the morbidity of this disease is limited in Japan. Using the HPLC screening method we have established recently, we examined samples of urine of 105 patients (73 males and 32 females) with developmental disabilities at our medical center. And we have found a family with three ID boys with a novel missense mutation in SLC6A8. This is the second report of a Japanese family case of CTD. A systematic diagnostic system of this syndrome should be established in Japan to enable us to estimate its frequency and treatment.