Seizures in Klinefelter's syndrome

Copy Number Variation and Epilepsy: State of the Art in the Era of High-Throughput Sequencing-A Multicenter Cohort Study

BACKGROUND

Genetic epilepsy diagnosis is increasing due to technological advancements. Although the use of molecular diagnosis is increasing, chromosomal microarray analysis (CMA) remains an important diagnostic tool for many patients. We aim to explore the role and indications of CMA in epilepsy, given the current genomic advances.

METHODS

We obtained data from 378 epileptic described patients, who underwent CMA between 2015 and 2021. Different types of syndromic or nonsyndromic epilepsy were represented.

RESULTS

After excluding patients who were undertreated or had missing data, we included 250 patients with treated epilepsy and relevant clinical information. These patients mostly had focal epilepsy or developmental and epileptic encephalopathy, with a median start age of 2 years. Ninety percent of the patients had intellectual disability, more than two thirds had normal head size, and 60% had an abnormal magnetic resonance imaging. We also included 10 patients with epilepsy without comorbidities. In our cohort, we identified 35 pathogenic copy number variations (CNVs) explaining epilepsy with nine recurrent CNVs enriched in patients with epilepsy, 12 CNVs related to neurodevelopmental disorder phenotype with possible epilepsy, five CNVs including a gene already known in epilepsy, and nine CNVs based on size combined with de novo occurrence. The diagnosis rate in our study reached 14% (35 of 250) with first-line CMA, as previously reported. Although targeted gene panel sequencing could potentially diagnose some of the reported epilepsy CNVs (34% [12 of 35]).

CONCLUSIONS

CMA remains a viable option as the first-line genetic test in cases where other genetic tests are not available and as a second-line diagnostic technique if gene panel or exome sequencing yields negative results.

Copy Number Variation and Structural Genomic Findings in 116 Cases of Sudden Unexplained Death between 1 and 28 Months of Age

In sudden unexplained death in pediatrics (SUDP) the cause of death is unknown despite an autopsy and investigation. The role of copy number variations (CNVs) in SUDP has not been well-studied. Chromosomal microarray (CMA) data are generated for 116 SUDP cases with age at death between 1 and 28 months. CNVs are classified using the American College of Medical Genetics and Genomics guidelines and CNVs in our cohort are compared to an autism spectrum disorder (ASD) cohort, and to a control cohort. Pathogenic CNVs are identified in 5 of 116 cases (4.3%). Variants of uncertain significance (VUS) favoring pathogenic CNVs are identified in 9 cases (7.8%). Several CNVs are associated with neurodevelopmental phenotypes including seizures, ASD, developmental delay, and schizophrenia. The structural variant 47,XXY is identified in two cases (2/69 boys, 2.9%) not previously diagnosed with Klinefelter syndrome. Pathogenicity scores for deletions are significantly elevated in the SUDP cohort versus controls (p = 0.007) and are not significantly different from the ASD cohort. The finding of pathogenic or VUS favoring pathogenic CNVs, or structural variants, in 12.1% of cases, combined with the observation of higher pathogenicity scores for deletions in SUDP versus controls, suggests that CMA should be included in the genetic evaluation of SUDP.

Educational status, testosterone replacement, and intelligence outcomes in Klinefelter syndrome

Most male hypergonadotropic hypogonadism associated with infertility can be attributed to a single genetic condition such as Klinefelter syndrome (KS). This disease's wide phenotypic variability is frequently associated with mosaic 47,XXY lineages and testosterone replacement. Early diagnosis and treatment have been associated with better cognitive and intellectual outcomes, but the scope of this influence requires further investigation.

Objective

This study aimed to investigate the intelligence profile of a cohort of patients with KS, considering the influence of educational level and clinical variables.

Methods

Twenty-nine (9-65 years) individuals were submitted to the measures of intelligence quotient (IQ) (Wechsler's Scales) and adaptive behavior (Vineland-II). Linear regression analysis included the participants' educational level and clinical variables (i.e., comorbidities and use of testosterone) as predictors and intellectual performance and adaptive behavior as outcomes.

Results

Scores varied from intellectual deficiency to average ranges (82.5+15.8). There were significant differences between adult's and children's IQ and between verbal and nonverbal indexes. The level of education predicted both IQ and adaptive behavior. Testosterone replacement therapy and absence of seizures predicted only adaptive behavior.

Conclusions

The level of education and hormonal therapy can be selectively implicated in the intellectual variability in KS.

Intelligence Quotient Variability in Klinefelter Syndrome Is Associated With GTPBP6 Expression Under Regulation of X-Chromosome Inactivation Pattern

Klinefelter syndrome (KS) displays a broad dysmorphological, endocrinological, and neuropsychological clinical spectrum. We hypothesized that the neurocognitive dysfunction present in KS relies on an imbalance in X-chromosome gene expression. Thus, the X-chromosome inactivation (XCI) pattern and neurocognitive X-linked gene expression were tested and correlated with intelligence quotient (IQ) scores. We evaluated 11 KS patients by (a) IQ assessment, (b) analyzing the XCI patterns using both HUMARA and ZDHHC15 gene assays, and (c) blood RT-qPCR to investigate seven X-linked genes related to neurocognitive development (GTPBP6, EIF2S3, ITM2A, HUWE1, KDM5C, GDI1, and VAMP7) and XIST in comparison with 14 (male and female) controls. Considering IQ 80 as the standard minimum reference, we verified that the variability in IQ scores in KS patients seemed to be associated with the XCI pattern. Seven individuals in the KS group presented a random X-inactivation (RXI) and lower average IQ than the four individuals who presented a skewed X-inactivation (SXI) pattern. The evaluation of gene expression showed higher GTPBP6 expression in KS patients with RXI than in controls (p = 0.0059). Interestingly, the expression of GTPBP6 in KS patients with SXI did not differ from that observed in controls. Therefore, our data suggest for the first time that GTPBP6 expression is negatively associated with full-scale IQ under the regulation of the type of XCI pattern. The SXI pattern may regulate GTPBP6 expression, thereby dampening the impairment in cognitive performance and playing a role in intelligence variability in individuals with KS, which warrants further mechanistic investigations.

Klinefelter's Syndrome with Maternal Uniparental Disomy X, Interstitial Xp22.31 Deletion, X-linked Ichthyosis, and Severe Central Nervous System Regression

We presented in this article a patient with Klinefelter syndrome (KS) (47,XXY) who had maternal nondisjunction and uniparental disomy of the X chromosome with regions of heterodisomy and isodisomy, an interstitial Xp22.31 deletion of both X chromosomes, and other problems. His mother also possesses the same Xp22.31 deletion. The patient presented with status epilepticus and stroke, followed by severe brain atrophy and developmental regression. His unusual clinical and cytogenetic findings apparently have not been reported with either KS or Xp22.31 deletions. Based on the patient's available genetic and biochemical information, we cannot satisfactorily explain his seizures, strokes, or catastrophic brain regression.

Klinefelter syndrome or testicular dysgenesis: Genetics, endocrinology, and neuropsychology

Klinefelter syndrome (47,XXY) is a frequent chromosomal disorder among males, often presenting with hypergonadotropic hypogonadism, small firm testicles, metabolic disorders, neurocognitive challenges, and increased height. Neurologic disorders such as epilepsy, seizures, and tremor as well as psychiatric disorders are also seen more frequently. The neurocognitive deficits seen are present in many areas of cognition, typically affecting general cognitive abilities, language, and executive functioning. Also, social dysfunction is frequent. Dyslexia is present in more than half of all males. Brain imaging studies generally show a typical pattern, with many nuclei and brain areas being smaller than among controls. However, it has not been possible to link the brain alterations found in imaging studies with the neurocognitive profile. The genetics underlying the phenotypic traits found among males with Klinefelter syndrome still remains to be elucidated; however, recent studies have described pervasive changes in the methylome and transcriptome and new and interesting candidate genes have been pinpointed, but their involvement in the phenotype of Klinefelter syndrome has not been proven.

PCDH19-related epilepsy in a male with Klinefelter syndrome: Additional evidence supporting PCDH19 cellular interference disease mechanism

Heterozygous de novo or inherited pathogenic variants in the PCDH19 gene cause a spectrum of neurodevelopmental features including developmental delay and seizures. PCDH19 epilepsy was previously known as "epilepsy and mental retardation limited to females", since the condition almost exclusively affects females. It is hypothesized that the co-existence of two populations of neurons, some with and some without PCDH19 protein expression, results in pathologically abnormal interactions between these neurons, a mechanism also referred to as cellular interference. Consequently, PCDH19-related epilepsies are inherited in an atypical X-linked pattern, such that hemizygous, non-mosaic, 46,XY males are typically unaffected, while individuals with a disease-causing PCDH19 variant, mainly heterozygous females and mosaic males, are affected. As a corollary to this hypothesis, an individual with Klinefelter syndrome (KS) (47,XXY) who has a heterozygous disease-causing PCDH19 variant should develop PCDH19-related epilepsy. Here, we report such evidence: - a male child with KS and PCDH19-related epilepsy - supporting the PCDH19 cellular interference disease hypothesis.

Next Generation Sequencing Methods for Diagnosis of Epilepsy Syndromes

Epilepsy is a neurological disorder characterized by an increased predisposition for seizures. Although this definition suggests that it is a single disorder, epilepsy encompasses a group of disorders with diverse aetiologies and outcomes. A genetic basis for epilepsy syndromes has been postulated for several decades, with several mutations in specific genes identified that have increased our understanding of the genetic influence on epilepsies. With 70-80% of epilepsy cases identified to have a genetic cause, there are now hundreds of genes identified to be associated with epilepsy syndromes which can be analyzed using next generation sequencing (NGS) techniques such as targeted gene panels, whole exome sequencing (WES) and whole genome sequencing (WGS). For effective use of these methodologies, diagnostic laboratories and clinicians require information on the relevant workflows including analysis and sequencing depth to understand the specific clinical application and diagnostic capabilities of these gene sequencing techniques. As epilepsy is a complex disorder, the differences associated with each technique influence the ability to form a diagnosis along with an accurate detection of the genetic etiology of the disorder. In addition, for diagnostic testing, an important parameter is the cost-effectiveness and the specific diagnostic outcome of each technique. Here, we review these commonly used NGS techniques to determine their suitability for application to epilepsy genetic diagnostic testing.

A Case Report of Klinefelter Syndrome with Schizophrenia-Like Psychosis and Seizure Disorder

Klinefelter syndrome is a disorder of variation of sex chromosome, the most common karyotype being 47XXY. Multiple case reports and articles have been published linking the increased prevalence of psychiatric disorders like Schizophrenia, Schizophreniform psychosis, Attention deficit hyperkinetic disorder, Learning disorder, etc. and seizure disorder in Klinefelter syndrome than in general population, attributing to the extra X chromosome. Here is a case of a 45-year-old gentleman with Klinefelter syndrome with schizophrenia-like psychosis and seizure disorder. He was diagnosed as Klinefelter syndrome 15 years back by genetic testing (47XXY) when he was investigated for infertility. His luteinizing hormone (LH) (32.04 mIU/ml) and follicle-stimulating hormone (FSH) (50.70 mIU/ml) levels were high and his testosterone level was low (1.76 ng/ml). He had four episodes of seizures in 2004 for which he was started on phenytoin and sodium valproate, and was seizure-free for past 10 years. He was brought to our hospital in July 2014 with complaints of talking and laughing to self, suspicion, hearing voices and aggressive behaviour, which were persistent mildly for past 15 years and aggravated for past 6 months. He was not going for work for past 15 years, does not mingle with relatives or friends.

Migrating partial seizures in infancy and 47XYY syndrome: Cause or coincidence?

Migrating partial seizures in infancy (MPSI) is a rare epilepsy syndrome with poor prognosis. The exact etiology of MPSI is still not known. We report a 14-month-old baby with 47XYY karyotype who presented with developmental delay and drug-refractory seizures satisfying the diagnostic criteria for MPSI and discuss the possible association between the 47XYY karyotype and this syndrome. The excess of genes due to an additional Y chromosome could cause disturbance in various stages of formation, migration, or differentiation of neurons. Depending on the degree of disturbance and the resultant cortical excitability, this could result in various epilepsy syndromes. We feel that this association is more likely causal than coincidental. Chromosome studies need to be performed in more individuals with atypical and uncommon epilepsies. Multicenter studies are required to establish the association between epilepsy syndrome and these rare chromosome disorders.

Seizure activity following cochlear implantation: is it the implant?

OBJECTIVE

Cochlear implantation is a successful method of auditory rehabilitation. This procedure has been associated with facial nerve and vestibular end-organ stimulation suggesting potential for extra-cochlear stimulation. The objectives of this study were to investigate the potential relationship between cochlear implantation and seizure activity in the pediatric implant population.

METHODS

Local Research Ethics Board approval was obtained. The Hospital for Sick Children's Cochlear Implant Database from 1998 to 2011 was retrospectively reviewed. Based on a multidisciplinary team, patients who received a diagnosis of seizure disorder or had been investigated for seizure-like activity were identified and reviewed.

RESULTS

Fifteen children from a group of 816 pediatric cochlear implant users were identified as having suspected seizure-like activity. Eventually 10 children were found to have seizures based on an evaluation by a pediatric neurologist and an electroencephalogram. Of these 10, only 3 children had new onset of seizures after cochlear implantation and 2 of these 3 suffered from global developmental delay and other medical comorbidities. No definite temporal connection was found between cochlear implant use and seizure activity.

CONCLUSIONS

Cochlear implantation in the pediatric population continues to be a reliable and safe intervention for children. Overall the prevalence of post implantation seizure disorders in our population (0.37%) is lower than that of the overall population (0.5-1%). The presence of new-onset seizure activity following cochlear implantation is unusual and while there are theoretic possibilities of how a cochlear implant could be implicated in initiating seizures we were unable to find evidence to support this association.

Klinefelter's syndrome complicated with West syndrome in a 4-month-old boy

We, for the first time, report a boy with West syndrome associated with Klinefelter's syndrome. He developed episodes of repetitive tonic spasms at the age of 4 months. He had developmental delays and hypsarrhythmia on interictal electroencephalography recording. His karyotype turned out to be 47, XXY, while we failed to observe anomalies in his appearance. Adrenocorticotropic hormone therapy with antiepileptic drugs resulted in cessation of tonic spasms, and his developmental quotient was improved by the age of 1 year. Further studies are needed to determine the causal association between West syndrome and Klinefelter's syndrome.

Variable associations of Klinefelter syndrome in children

BACKGROUND

KF is characterized by heterogeneity in the degree of expressed phenotypes.

OBJECTIVE

to ascertain the variable phenotypes of Klinefelter syndrome in children.

SUBJECTS AND METHODS

We present eight klinefelter patients, their age ranged from 2 to 11 years (mean 6.63). Subjects were meticulously examined for evidence of dysmorphology. Intelligence quotient was estimated.

RESULTS

Cytogenetic analysis revealed 47,XXY karyotype in all patients. The following was detected: Dysmorphism in 5/8, micropenis in 4/8, the left testis was nonpalpable in 4/8, short stature in 4/8, congenital cardiac malformations in 4/8, seizures in 4/8, mental retardation in 5/8, growth hormone deficiency in 2/8, hypothyroidism and delayed bone age in 1/8.

CONCLUSION

Our study demonstrated a variable association of mental retardation, dysmorphism, micropenis, undescended testis, seizures, congenital heart defects, and growth hormone deficiency among Egyptian patients with Klinefelter syndrome. This merits further study to facilitate earlier diagnosis and better management to improve their quality of life.

Epilepsy and chromosomal abnormalities

Background

Many chromosomal abnormalities are associated with Central Nervous System (CNS) malformations and other neurological alterations, among which seizures and epilepsy. Some of these show a peculiar epileptic and EEG pattern. We describe some epileptic syndromes frequently reported in chromosomal disorders.

Methods

Detailed clinical assessment, electrophysiological studies, survey of the literature.

Results

In some of these congenital syndromes the clinical presentation and EEG anomalies seems to be quite typical, in others the manifestations appear aspecific and no strictly linked with the chromosomal imbalance. The onset of seizures is often during the neonatal period of the infancy.

Conclusions

A better characterization of the electro clinical patterns associated with specific chromosomal aberrations could give us a valuable key in the identification of epilepsy susceptibility of some chromosomal loci, using the new advances in molecular cytogenetics techniques - such as fluorescent in situ hybridization (FISH), subtelomeric analysis and CGH (comparative genomic hybridization) microarray. However further studies are needed to understand the mechanism of epilepsy associated with chromosomal abnormalities.

A novel CDKL5 mutation in a 47,XXY boy with the early-onset seizure variant of Rett syndrome

Mutations of the cyclin-dependent kinase-like 5 gene (CDKL5), reported almost exclusively in female subjects, have been recently found to be the cause of a phenotype overlapping Rett syndrome with early-onset epileptic encephalopathy. We describe the first CDKL5 mutation detected in a male individual with 47,XXY karyotype. This previously unreported, de novo, mutation truncates the large CDKL5 COOH-terminal region, thought to be crucial for the proper sub-cellular localization of the CDKL5 protein. The resulting phenotype is characterized by a severe early-onset epileptic encephalopathy, global developmental delay, and profound intellectual and motor impairment with features reminiscent of Rett syndrome. In light of the data presented we discuss the possible phenotypic modulatory effects of the supernumerary wild type X allele and pattern of X chromosome inactivation and stress the importance of considering the causal involvement of CDKL5 in developmentally delayed males with early-onset seizures.

Two Boys with 47, XXY and Autism

Two children with autism and Klinefelter syndrome (KS) (47, XXY) are presented. Both qualify for the diagnosis of autism based on DSM-IV with severely delayed and disordered language, difficulties with social interaction, and a restricted range of interests and activities. Both also have abnormal EEGs, and one patient has had what appear to be clinical seizures. Trials of antiepileptic medications have not been beneficial in either patient. We report the clinical and EEG findings of each patient, and discuss the implications of this combination of disorders.

Klinefelter's syndrome with seizure, pseudohypoparathyroidism type Ib and multiple endocrine dysfunctions

Klinefelter's syndrome is rarely associated with hypocalcemia, especially pseudohypoparathyroidism (PHP) type Ib. We describe a case of Klinefelter's syndrome associated with seizure, PHP type Ib and multiple endocrine dysfunctions. A 19-year-old Taiwanese male was admitted due to seizures with loss of consciousness. He had been diagnosed with Klinefelter's syndrome with seizure disorder and hypocalcemia 3 months previously. Physical examination revealed eunuchoidism but no osteodystrophy, while laboratory data revealed severe hypocalcemia, hyperphosphatemia, and elevated parathyroid hormone. Chromosomal study showed 47,XXY. Osteoporosis was found on chest and abdominal radiography. Dense calcification in the cerebrum and cerebellum was shown on brain computed tomography and magnetic resonance imaging. Elevation of the patient's serum calcium level was noted after vitamin D and calcium carbonate supplements were given. Klinefelter's syndrome is rarely associated with PHP type Ib; our patient's hypocalcemia improved after long-term aggressive treatment.

Electroencephalographic and Epileptic Patterns in X Chromosome Anomalies

Although epilepsy and mental retardation are commonly observed in individuals with chromosomal aberrations, the identification of EEG/epileptic profiles in those with specific chromosome anomalies remains difficult. A few syndromes seem to show peculiar clinical and EEG associations. The authors report an electroclinical investigation on a group of patients carrying X chromosome anomalies: 16 patients with Turner's syndrome, 17 with Klinefelter's syndrome, 1 with an X-autosomal rearrangement, 2 with Xq isochromosome [Xq(i)], and 7 with triple X syndrome. Epilepsy and/or EEG anomalies were found in three of the patients with Klinefelter's syndrome, in one patient with an X-autosomal rearrangement, and in five of those with triple X syndrome. No epilepsy or EEG anomalies were detected in the other patients. Epilepsy may be associated with Klinefelter's syndrome. In addition, the authors found that an electroclinical pattern, represented by paroxysmal activity in the posterior regions (temporo-parieto-occipital areas) with complex partial seizures and easily controlled by antiepileptic drugs, may be present in patients with triple X syndrome. In contrast, gross X-autosomal rearrangements are associated with polymorphic EEG/epileptic findings. Although further studies are needed to validate these observations, they clearly confirm the strict relationship between X chromosome anomalies and epilepsy.