Josepha Yeshaya

Obsessive-compulsive disorder in patients with velocardiofacial (22q11 deletion) syndrome

The study of neurogenetic microdeletion syndromes provides an insight into the developmental psychopathology of psychiatric disorders. The aim of the study was to evaluate the prevalence of psychiatric disorders, especially obsessive‐compulsive disorder (OCD), in patients with velocardiofacial syndrome (VCFS), a 22q11 microdeletion syndrome. Forty‐three subjects with VCFS of mean age 18.3 ± 10.6 years were comprehensively assessed using semi‐structured psychiatric interview and the Yale–Brown obsessive compulsive scale (Y‐BOCS). Best estimate diagnoses were made on the basis of information gathered from subjects, parents, teachers, and social workers. Fourteen VCFS subjects (32.6%) met the DSM‐IV criteria for OCD. OCD had an early age of onset and generally responded to fluoxetine treatment. It was not related to mental retardation. The most common obsessive‐compulsive symptoms were contamination, aggression, somatic worries, hoarding, repetitive questions, and cleaning. Sixteen of the 43 patients (37.2%) had attention‐deficit/hyperactivity disorder (ADHD), and 7 (16.2%) had psychotic disorder. The results of our study suggest that there is a strong association between VCFS and early‐onset OCD. This finding may be significant in the understanding of the underlying genetic basis of OCD.

Association of the low-activity COMT 158Met allele with ADHD and OCD in subjects with velocardiofacial syndrome.

Velocardiofacial syndrome (VCFS) is caused by a microdeletion in chromosome 22 and is a risk factor for the development of schizophrenia and other psychiatric disorders. The catechol-O-methyltransferase (COMT), residing in the 22q11.2 microdeletion region, is a major candidate gene for genetic susceptibility to neuropsychiatric disorders in VCFS. Individuals with VCFS carrying the low-activity allele (COMTL) are expected to have the lowest possible COMT activity since they have only a single copy of the gene. We explored the possibility that COMTL is associated with psychiatric disorders commonly found in VCFS. Fifty-five unrelated individuals with VCFS underwent psychiatric evaluation and were genotyped for the COMT 158Val/Met polymorphism coding for COMT high/low-activity alleles. The COMTL allele was significantly more prevalent in VCFS subjects with attention deficit hyperactivity disorder (ADHD) (73.9% vs. 33.3%, OR 5.67, chi2=7.76, p=0.005) and obsessive-compulsive disorder (OCD) (78.6% vs. 33.3%, OR 7.33, chi2=7.24, p=0.007) than in the control group (VCFS subjects without OCD, ADHD and schizophrenia/schizoaffective (SZ/SZaff) disorder). The results of this study suggest that greatly reduced COMT activity, as expected in VCFS COMTL individuals may be a risk factor for psychiatric sequelae in this population. Future longitudinal studies focusing on additional COMT polymorphic sites and other candidate genes from the deleted region will elucidate the molecular pathways leading to schizophrenia and other psychiatric disorders in VCFS.

FISH-detected delay in replication timing of mutated FMR1 alleles on both active and inactive X-chromosomes

X-chromosome inactivation and the size of the CGG repeat number are assumed to play a role in the clinical, physical, and behavioral phenotype of female carriers of a mutated FMR1 allele. In view of the tight relationship between replication timing and the expression of a given DNA sequence, we have examined the replication timing of FMR1 alleles on active and inactive X-chromosomes in cell samples (lymphocytes or amniocytes) of 25 females: 17 heterozygous for a mutated FMR1 allele with a trinucleotide repeat number varying from 58 to a few hundred, and eight homozygous for a wild-type allele. We have applied two-color fluorescence in situ hybridization (FISH) with FMR1 and X-chromosome α-satellite probes to interphase cells of the various genotypes: the α-satellite probe was used to distinguish between early replicating (active) and late replicating (inactive) X-chromosomes, and the FMR1 probe revealed the replication pattern of this locus. All samples, except one with a large trinucleotide expansion, showed an early replicating FMR1 allele on the active X-chromosome and a late replicating allele on the inactive X-chromosome. In samples of mutation carriers, both the early and the late alleles showed delayed replication compared with normal alleles, regardless of repeat size. We conclude therefore that: (1) the FMR1 locus is subjected to X-inactivation; (2) mutated FMR1 alleles, regardless of repeat size, replicate later than wild-type alleles on both the active and inactive X-chromosomes; and (3) the delaying effect of the trinucleotide expansion, even with a low repeat size, is superimposed on the delay in replication associated with X-inactivation.

Replication timing of the various FMR1 alleles detected by FISH: inferences regarding their transcriptional status.

Abstract Following the application of two-color fluorescence in-situ hybridization (FISH) to human interphase cells, we examined the replication timing of the fragile-X locus relative to the non-transcribed late replicating α-satellite region of chromosome-X, a built-in intracellular reference locus. In this assay, an unreplicated locus is identified by a single hybridization signal (singlet; S), whereas a replicated locus is identified by a duplicated signal (doublet; D). Hence, following simultaneous hybridization with the FMR1 and α-satellite probes, male cells with one singlet and one doublet signal per cell (SD cells) indicate S-phase cells where only one of the two loci has replicated. The studied cell samples (lymphocytes and amniocytes) were derived from normal males, fragile-X male patients, and premutation male carriers. Three distinct populations of SD cells were identified among the various samples. The first population had a high frequency of cells showing a doublet FMR1; this pattern, indicating early replication of FMR1, characterized the SD cell population of normal males. The second population had a high frequency of cells showing a singlet FMR1; this pattern, indicating very late replication of FMR1, characterized the SD population of fragile-X patients. The third population had about one half of the cells showing a singlet FMR1 and the other half with a doublet FMR1, indicating somatic variation in the replication timing of FMR1; this pattern was seen in the SD cell population of premutation carriers. The replication status of the FMR1 locus in the cells of patients was altered from late to early in the presence of 5-azadeoxycytidine, an activator of various silent genes. Based on the vast amount of information showing that expressed loci replicate early, whereas unexpressed loci replicate late, we inferred from the replication status of the FMR1 locus that: (1) the normal FMR1 allele is transcriptionally active in lymphocytes and amniocytes; (2) the fully mutated FMR1 allele is transcriptionally silent; (3) the transcriptional activity of the premutated allele is somewhat disturbed; (4) 5-azadeoxycytidine activates the fully mutated FMR1 allele.

Chromosomal microarray analysis in fetuses with aberrant right subclavian artery

To evaluate the association between aberrant right subclavian artery (ARSA), with or without additional risk factors for aneuploidy or ultrasound abnormality, and results of chromosomal microarray analysis (CMA).

Microdeletion syndromes disclose replication timing alterations of genes unrelated to the missing DNA

BackgroundThe temporal order of allelic replication is interrelated to the epigenomic profile. A significant epigenetic marker is the asynchronous replication of monoallelically-expressed genes versus the synchronous replication of biallelically-expressed genes. The present study sought to determine whether a microdeletion in the genome affects epigenetic profiles of genes unrelated to the missing segment. In order to test this hypothesis, we checked the replication patterns of two genes – SNRPN, a normally monoallelically expressed gene (assigned to 15q11.13), and the RB1, an archetypic biallelically expressed gene (assigned to 13.q14) in the genomes of patients carrying the 22q11.2 deletion (DiGeorge/Velocardiofacial syndrome) and those carrying the 7q11.23 deletion (Williams syndrome).ResultsThe allelic replication timing was determined by fluorescence in situ hybridization (FISH) technology performed on peripheral blood cells. As expected, in the cells of normal subjects the frequency of cells showing asynchronous replication for SNRPN was significantly (P < 10-12) higher than the corresponding value for RB1. In contrast, cells of the deletion-carrying patients exhibited a reversal in this replication pattern: there was a significantly lower frequency of cells engaging in asynchronous replication for SNRPN than for RB1 (P < 10-4 and P < 10-3 for DiGeorge/Velocardiofacial and Williams syndromes, respectively). Accordingly, the significantly lower frequency of cells showing asynchronous replication for SNRPN than for RB1 is a new epigenetic marker distinguishing these deletion syndrome genotypes from normal ones.ConclusionIn cell samples of each deletion-carrying individual, an aberrant, reversed pattern of replication is delineated, namely, where a monoallelic gene replicates more synchronously than a biallelic gene. This inverted pattern, which appears to be non-deletion-specific, clearly distinguishes cells of deletion-carriers from normal ones. As such, it offers a potential epigenetic marker for suspecting a hidden microdeletion that is too small to be detected by conventional karyotyping methods.

A de-novo interstitial microduplication involving 2p16.1-p15 and mirroring 2p16.1-p15 microdeletion syndrome: Clinical and molecular analysis

BACKGROUND Microdeletions of various sizes in the 2p16.1-p15 chromosomal region have been grouped together under the 2p16.1-p15 microdeletion syndrome. Children with this syndrome generally share certain features including microcephaly, developmental delay, facial dysmorphism, urogenital and skeletal abnormalities. We present a child with a de-novo interstitial 1665 kb duplication of 2p16.1-p15. METHODS AND RESULTS Clinical features of this child are distinct from those of children with the 2p16.1-p15 microdeletion syndrome, specifically the head circumference which is within the normal range and mild intellectual disability with absence of autistic behaviors. Microduplications many times bear milder clinical phenotypes in comparison with corresponding microdeletion syndromes. Indeed, as compared to the microdeletion syndrome patients, the 2p16.1-p15 microduplication seems to have a milder cognitive effect and no effect on other body systems. Limited information available in genetic databases about cases with overlapping duplications indicates that they all have abnormal developmental phenotypes. CONCLUSION The involvement of genes in this location including BCL11A, USP34 and PEX13, affecting fundamental developmental processes both within and outside the nervous system may explain the clinical features of the individual described in this report.

Acute promyelocytic leukemia with isochromosome 17q and cryptic PML-RARA successfully treated with all-trans retinoic acid and arsenic trioxide.

Acute promyelocytic leukemia (APL) is a subtype of acute leukemia that is characterized by typical morphology, bleeding events and distinct chromosomal aberrations, usually the t(15;17)(q22;q21) translocation. Approximately 9% of APL patients harbor other translocations involving chromosome 17, such as the t(11;17)(q23;q21), t(5;17)(q35;q12-21), t(11;17)(q13;q21), and der(17). All-trans retinoic acid (ATRA) and arsenic trioxide (ATO) have specific targeted activities against the PML-RARA fusion protein. The combination of ATRA and ATO is reportedly superior to chemotherapy and ATRA as induction therapy for APL. The clinical significance of non-t(15:17) APL-related aberrations is controversial, with conflicting reports regarding sensitivity to modern, targeted therapy. Isochromosome 17q (iso(17q)) is rarely associated with APL and usually occurs concurrently with the t(15:17) translocation. No published data is available regarding the efficacy of ATO-based therapy for APL patients who harbor iso(17q). We report on an APL patient with iso(17q) as the sole cytogenetic aberration and a cryptic PML-RARA transcript, who was treated with ATRA and ATO after failure of chemotherapy and achieved complete remission. To our knowledge, this is the first published report of APL associated with iso(17q) as the sole cytogenetic aberration, which was successfully treated with an ATO containing regimen.

When genotype is not predictive of phenotype: implications for genetic counseling based on 21,594 chromosomal microarray analysis examinations

PurposeTo compare the frequency of copy-number variants (CNVs) of variable penetrance in low-risk and high-risk prenatal samples and postnatal samples.MethodsTwo cohorts were categorized according to chromosomal microarray analysis (CMA) indication: group I, low-risk prenatal—women with uneventful pregnancy (control group); group II, high-risk prenatal—women whose fetuses had congenital malformations; and group III, postnatal—individuals with unexplained developmental delay/intellectual disability, autism spectrum disorders, or multiple congenital anomalies. CNVs were categorized based on clinical penetrance: (i) high (>40%), (ii) moderate (10–40%), and (iii) low (<10%).ResultsFrom 2013 to 2016, 21,594 CMAs were performed. The frequency of high-penetrance CNVs was 0.1% (21/15,215) in group I, 0.9% (26/2,791) in group II, and 2.6% (92/3,588) in group III. Moderate-penetrance CNV frequency was 0.3% (47/15,215), 0.6% (19/2,791), and 1.2% (46/3,588), respectively. These differences were statistically significant. The frequency of low-penetrance CNVs was not significantly different among groups: 0.6% (85/15,215), 0.9% (25/2,791), and 1.0% (35/3,588), respectively.ConclusionHigh-penetrance CNVs might be a major factor in the overall heritability of developmental, intellectual, and structural anomalies. Low-penetrance CNV alone does not seem to contribute to these anomalies. These data may assist pre- and posttest CMA counseling.

Abnormal brain magnetic resonance imaging in two patients with Smith–Magenis syndrome

Smith–Magenis syndrome (SMS) is a clinically recognizable contiguous gene syndrome ascribed to an interstitial deletion in chromosome 17p11.2. Seventy percent of SMS patients have a common deletion interval spanning 3.5 megabases (Mb). Clinical features of SMS include characteristic mild dysmorphic features, ocular anomalies, short stature, brachydactyly, and hypotonia. SMS patients have a unique neurobehavioral phenotype that includes intellectual disability, self‐injurious behavior and severe sleep disturbance. Little has been reported in the medical literature about anatomical brain anomalies in patients with SMS. Here we describe two patients with SMS caused by the common deletion in 17p11.2 diagnosed using chromosomal microarray (CMA). Both patients had a typical clinical presentation and abnormal brain magnetic resonance imaging (MRI) findings. One patient had subependymal periventricular gray matter heterotopia, and the second had a thin corpus callosum, a thin brain stem and hypoplasia of the cerebellar vermis. This report discusses the possible abnormal MRI images in SMS and reviews the literature on brain malformations in SMS. Finally, although structural brain malformations in SMS patients are not a common feature, we suggest baseline routine brain imaging in patients with SMS in particular, and in patients with chromosomal microdeletion/microduplication syndromes in general. Structural brain malformations in these patients may affect the decision‐making process regarding their management.