Neurological features and long-term follow-up in 15q11.2-13.1 duplication

Microduplications at the 15q11.2 BP1-BP2 locus are enriched in patients with anorexia nervosa

Microduplication at 15q11.2 have been reported in genetic association studies of schizophrenia and autism. Given the potential overlap in psychiatric symptoms of schizophrenia and autism with anorexia nervosa (AN), we were inspired to test the association of this CNV locus with the genetic susceptibility of AN using ParseCNV, a highly quality controlled CNV pipeline developed by our group. The CNV analysis was performed in 1017 AN cases and 7250 controls using the Illumina HumanHap610 SNP arrays data. We uncovered association of the 15q11.2 microduplication with AN with P = 0.00023, while no genetic association between the microdeletion of this region and AN was identified. Among four genes in this region that are not imprinted, NIPA1 has the highest expression in brain and encodes a magnesium transporter protein on early endosomes and the cell surface in neurons. Targeting at Mg2+ uptake mediated by NIPA1 presents an interesting research topic for the explorations of novel therapy for AN and other neurobehavioral diseases, such as schizophrenia and autism.

High-functioning autism spectrum disorder with fluent speech and late-onset epilepsy: an unusual presentation of Inv-Dup (15) syndrome

Many neuropsychiatric phenotypes have been reported in association with rearrangements in the 15q11-q13 region. Clinical presentations can include hypotonia, developmental delay, severe/moderate intellectual disabilities, poor expressive language, difficult to treat epilepsy, and autism spectrum disorders. Here we report an additional case of a girl with inversion duplication on chromosome 15 (Inv-Dup 15) showing a peculiar and milder clinical phenotype, including atypical high-functioning autism disorder, late onset and drug-responsive epilepsy, and a relatively good language development . This report suggests that a diagnosis of Inv-Dup (15) can be suspected during more benign atypical condition with a better outcome than usually reported.

Electroclinical features of epilepsy in patients with InvDup(15)

PURPOSE

InvDup(15) syndrome is one of the most common chromosomal abnormalities associated with epilepsy. Here we review the seizure types described in InvDup(15) patients and the main electroclinical, therapeutic, and prognostic aspects of the syndrome.

METHODS

A literature search of PubMed, MEDLINE, and EMBASE was performed to identify papers examining InvDup(15) syndrome and epilepsy.

RESULTS

About 65% of the InvDup(15) patients described in the literature had multiple seizure types with a predominance (40.4%) of tonic-clonic seizures. Age at seizure onset was before 10 years in more than half of them. Patients suffered from a variety of EEG abnormalities, generalized spike activity being the most frequent. Brain MRI was unremarkable in the majority of patients. Treatment was with several anticonvulsant drugs used as mono- or polytherapy. Valproic acid was the most common treatment against generalized seizures and was often effective, although drug resistance was a major concern in a large number of cases. Finally, more than 30% of the children suffered from infantile spasms, and status epilepticus was described in nearly 20% of patients, occasionally resulting in death.

CONCLUSION

Seizures are very common in InvDup(15) patients, who suffer from a variety of seizure types. Information about EEG and brain MRI findings, seizure treatment, and prognosis is often poor. The overall prognosis is fair. Prospective studies of larger samples are needed, to gain further insights into the natural history of InvDup(15) syndrome.

Unraveling the genetic architecture of copy number variants associated with schizophrenia and other neuropsychiatric disorders

Recent studies show that the complex genetic architecture of schizophrenia (SZ) is driven in part by polygenic components, or the cumulative effect of variants of small effect in many genes, as well as rare single-locus variants with large effect sizes. Here we discuss genetic aberrations known as copy number variants (CNVs), which fall in the latter category and are associated with a high risk for SZ and other neuropsychiatric disorders. We briefly review recurrent CNVs associated with SZ, and then highlight one CNV in particular, a recurrent 1.6-Mb deletion on chromosome 3q29, which is estimated to confer a 40-fold increased risk for SZ. Additionally, we describe the use of genetic mouse models, behavioral tools, and patient-derived induced pluripotent stem cells as a means to study CNVs in the hope of gaining mechanistic insight into their respective disorders. Taken together, the genomic data connecting CNVs with a multitude of human neuropsychiatric disease, our current technical ability to model such chromosomal anomalies in mouse, and the existence of precise behavioral measures of endophenotypes argue that the time is ripe for systematic dissection of the genetic mechanisms underlying such disease. © 2016 Wiley Periodicals, Inc.

Three gangliogliomas: results of GTG-banding, SKY, genome-wide high resolution SNP-array, gene expression and review of the literature

According to the World Health Organization gangliogliomas are classified as well-differentiated and slowly growing neuroepithelial tumors, composed of neoplastic mature ganglion and glial cells. It is the most frequent tumor entity observed in patients with long-term epilepsy. Comprehensive cytogenetic and molecular cytogenetic data including high-resolution genomic profiling (single nucleotide polymorphism (SNP)-array) of gangliogliomas are scarce but necessary for a better oncological understanding of this tumor entity. For a detailed characterization at the single cell and cell population levels, we analyzed genomic alterations of three gangliogliomas using trypsin-Giemsa banding (GTG-banding) and by spectral karyotyping (SKY) in combination with SNP-array and gene expression array experiments. By GTG and SKY, we could confirm frequently detected chromosomal aberrations (losses within chromosomes 10, 13 and 22; gains within chromosomes 5, 7, 8 and 12), and identify so far unknown genetic aberrations like the unbalanced non-reciprocal translocation t(1;18)(q21;q21). Interestingly, we report on the second so far detected ganglioglioma with ring chromosome 1. Analyses of SNP-array data from two of the tumors and respective germline DNA (peripheral blood) identified few small gains and losses and a number of copy-neutral regions with loss of heterozygosity (LOH) in germline and in tumor tissue. In comparison to germline DNA, tumor tissues did not show substantial regions with significant loss or gain or with newly developed LOH. Gene expression analyses of tumor-specific genes revealed similarities in the profile of the analyzed samples regarding different relevant pathways. Taken together, we describe overlapping but also distinct and novel genetic aberrations of three gangliogliomas.