9p Duplication Research Articles

Clinical and molecular delineation of duplication 9p24.3q21.11 in a patient with psychotic behavior

This article describes a 19-year-old female with mild facial dysmorphism, asociality, decreased school performance, and psychotic behavior in whom the karyotype showed an extra-chromosomal marker characterized as 9p24.3–9q21.11 duplication by array-CGH. The 69Mbp duplicated segment in this patient includes the critical 9p duplication syndrome region, the GLDC and C90RF72 genes associated with psychotic behavior and other conduct disorders, and a potential locus for autism.

Trisomía parcial 4p por cromosoma 4 recombinante originado por inversión pericéntrica de origen paterno

La trisomía parcial 4p, suele originarse de translocaciones entre el cromosoma 4 y otros cromosomas no homólogos o por inversión pericéntrica del cromosoma 4, originando gametos anómalos entre el cromosoma normal y el invertido, obteniéndose un cromosoma recombinante que puede portar duplicidad de segmentos del brazo pequeño (4p) o del brazo largo (4q) siendo este último inviable. Las características fenotípicas de esta condición cursan con retardo mental severo, retraso en el desarrollo psicomotor, anomalías craneofaciales, estrabismo, defectos osteomusculares, defectos cardiacos, criptorquidia y micropene. Describimos el caso de un niño de 1 año 6 meses con retardo en el desarrollo psicomotor y rasgos dismórficos, presentando una duplicación 4p recombinante de origen paterno.Es el primer caso de duplicación 4p hallado en nuestra institución y debido al carácter hereditario, es preciso realizar la consejería a los progenitores y seguimiento del propósitos para su manejo terapéutico y psicológico.

Case of 7p22.1 Microduplication Detected by Whole Genome Microarray (REVEAL) in Workup of Child Diagnosed with Autism.

Introduction. More than 60 cases of 7p22 duplications and deletions have been reported with over 16 of them occurring without concomitant chromosomal abnormalities. Patient and Methods. We report a 29-month-old male diagnosed with autism. Whole genome chromosome SNP microarray (REVEAL) demonstrated a 1.3 Mb interstitial duplication of 7p22.1 ->p22.1 arr 7p22.1 (5,436,367–6,762,394), the second smallest interstitial 7p duplication reported to date. This interval included 14 OMIM annotated genes (FBXL18, ACTB, FSCN1, RNF216, OCM, EIF2AK1, AIMP2, PMS2, CYTH3, RAC1, DAGLB, KDELR2, GRID2IP, and ZNF12). Results. Our patient presented features similar to previously reported cases with 7p22 duplication, including brachycephaly, prominent ears, cryptorchidism, speech delay, poor eye contact, and outburst of aggressive behavior with autism-like features. Among the genes located in the duplicated segment, ACTB gene has been proposed as a candidate gene for the alteration of craniofacial development. Overexpression of RNF216L has been linked to autism. FSCN1 may play a role in neurodevelopmental disease. Conclusion. Characterization of a possible 7p22.1 Duplication Syndrome has yet to be made. Recognition of the clinical spectrum in patients with a smaller duplication of 7p should prove valuable for determining the minimal critical region, helping delineate a better prediction of outcome and genetic counseling

Chemoimmunotherapy Combining Vincristine, Dexamethasone and Epratuzumab (hLL2) As Salvage Regimen for Older Relapsed/Refractory, CD22+ B-Acute Lymphoblastic Leukemia (B-ALL) Patients: Results of the French Non-Intensive Phase 2 Prospective Cheprall Study

▪Purpose: Best supportive care is generally offered to older patients presenting with refractory/relapsed acute lymphoblastic leukemia (ALL). There is clearly a need for new therapeutic approaches in these older patients for whom aggressive chemotherapies cannot be administered.Materials and Methods: The present study evaluated the addition of epratuzumab (hLL2), a humanized monoclonal therapeutic antibody against CD22, to the combination of vincristine and dexamethasone in older patients (>55 years) with relapsed/refractory CD22+ B-ALL. The salvage regimen consisted of epratuzumab 360 mg/m²/d iv days 1, 8, 15, and 22, vincristine 2 mg iv days 1, 8, 15 and 22, and dexamethasone 40 mg/d po days 1, 8, 15, and 22. Morphologic and phenotypic minimal residual disease (MRD) responses were determined between 4 and 6 weeks from day 1.Results: Between November 2010 and December 2013, 26 patients from six French centers were enrolled in the study. One case was excluded because of progression before receiving the treatment, while 2 younger patients were inappropriately included (49-year old female in fourth relapse and 32-year old female with refractory second relapse). Among the 25 patients considered for analyses, there were 13 males and the median age was 65 years. Eighteen, 4, 1, and 1 patients were in first, second, third, and fourth relapse, respectively, and one case had refractory B-ALL. Median percentage of blasts in bone marrow was 72%. Karyotypes were as follow: normal n=8; Ph+ n=6, complex n=1, MLL rearrangement n=1, hyperdiploidy n=2, hypodiploidy n=2, 17p duplication n=1, del9p n=1, t(1;19) n=1, t(13;14) n=1, 14 abnormality n=1. Median interval between diagnosis and salvage regimen was 16 months. Three patients were previously allotransplanted. Two patients died of progression during treatment. Salvage regimen was overall well tolerated, since the large majority of grade 3/4 toxicities were expected pancytopenia. One grade 3 toxicity was related to the first epratuzumab infusion, but the patient received the three other infusions without events. One grade 3 renal injury and one grade 4 hypertriglyceridemia of unclear etiology also were documented.The overall response rate was 40% (n=10), including 4 complete responses (CR) and 1 CR with incomplete platelet recovery (CRp) (20%), and 5 partial responses (PR) (20%). Two patients in CR/CRp were documented with negative MRD. All patients in CR/CRp and 1 patient in PR received a second cycle as consolidation. All patients died of disease progression, except two non-responder cases. Median OS was 4 months (range: 0.5-43). Median DFS for those achieving CR/CRp was 4 months (range: 1-8).Conclusion: Non-intensive chemoimmunotherapy combining vincristine/dexamethasone/epratuzumab provides encouraging results in this very high-risk, refractory/relapsed, older population. These results pave the way for integrating epratuzumab within first-line chemotherapies in older CD22+ B-ALL patients. This trial is registered at http://clinicaltrials.gov/ct no.NCT01219816. DisclosuresLeguay:Gilead Sciences: Research Funding. Goldenberg:immunomedics: Employment. Wegener:immunomedics: Employment.

Duplication 9p and their implication to phenotype.

BackgroundTrisomy 9p is one of the most common partial trisomies found in newborns. We report the clinical features and cytogenomic findings in five patients with different chromosome rearrangements resulting in complete 9p duplication, three of them involving 9p centromere alterations.MethodsThe rearrangements in the patients were characterized by G-banding, SNP-array and fluorescent in situ hybridization (FISH) with different probes.ResultsTwo patients presented de novo dicentric chromosomes: der(9;15)t(9;15)(p11.2;p13) and der(9;21)t(9;21)(p13.1;p13.1). One patient presented two concomitant rearranged chromosomes: a der(12)t(9;12)(q21.13;p13.33) and an psu i(9)(p10) which showed FISH centromeric signal smaller than in the normal chromosome 9. Besides the duplication 9p24.3p13.1, array revealed a 7.3 Mb deletion in 9q13q21.13 in this patient. The break in the psu i(9)(p10) probably occurred in the centromere resulting in a smaller centromere and with part of the 9q translocated to the distal 12p with the deletion 9q occurring during this rearrangement. Two patients, brother and sister, present 9p duplication concomitant to 18p deletion due to an inherited der(18)t(9;18)(p11.2;p11.31)mat.ConclusionsThe patients with trisomy 9p present a well-recognizable phenotype due to facial appearance, although the genotype-phenotype correlation can be difficult due to concomitant partial monosomy of other chromosomes. The chromosome 9 is rich in segmental duplication, especially in pericentromeric region, with high degree of sequence identity to sequences in 15p, 18p and 21p, chromosomes involved in our rearrangements. Thus, we suggest that chromosome 9 is prone to illegitimate recombination, either intrachromosomal or interchromosomal, which predisposes it to rearrangements, frequently involving pericentromeric regions.

Analysis of genomic copy number variations in two unrelated neonates with 8p deletion and duplication associated with congenital heart disease

To screen for genomic copy number variations (CNVs) in two unrelated neonates with multiple congenital abnormalities using Affymetrix SNP chip and try to find the critical region associated with congenital heart disease. Two neonates were tested for genomic copy number variations by using Cytogenetic SNP chip.Rare CNVs with potential clinical significance were selected of which deletion segments' size was larger than 50 kb and duplication segments' size was larger than 150 kb based on the analysis of ChAs software, without false positive CNVs and segments of normal population. The identified CNVs were compared with those of the cases in DECIPHER and ISCA databases. Eleven rare CNVs with size from 546.6-27 892 kb were identified in the 2 neonates. The deletion region and size of case 1 were 8p23.3-p23.1 (387 912-11 506 771 bp) and 11.1 Mb respectively, the duplication region and size of case 1 were 8p23.1-p11.1 (11 508 387-43 321 279 bp) and 31.8 Mb respectively. The deletion region and size of case 2 were 8p23.3-p23.1 (46 385-7 809 878 bp) and 7.8 Mb respectively, the duplication region and size of case 2 were 8p23.1-p11.21 (12 260 914-40 917 092 bp) and 28.7 Mb respectively. The comparison with Decipher and ISCA databases supported previous viewpoint that 8p23.1 had been associated with congenital heart disease and the region between 7 809 878-11 506 771 bp may play a role in the severe cardiac defects associated with 8p23.1 deletions. Case 1 had serious cardiac abnormalities whose GATA4 was located in the duplication segment and the copy number increased while SOX7 was located in the deletion segment and the copy number decreased. The region between 7 809 878-11 506 771 bp in 8p23.1 is associated with heart defects and copy number variants of SOX7 and GATA4 may result in congenital heart disease.

A cryptic familial rearrangement of 11p15.5, involving both imprinting centers, in a family with a history of short stature

Silver-Russell syndrome (SRS) is a heterogeneous disorder characterized by intrauterine and postnatal growth retardation, dysmorphic facial features and body asymmetry. Both hypomethylation of the telomeric imprinting control region 1 (ICR1) at 11p15.5 and maternal duplication of 11p15.5 have been implicated in the etiology of this disorder. Here we report the origin and segregation of the first reported between-arm intrachromosomal insertion of 11p15.5 that encompasses both ICR1 and ICR2 in a multigenerational family with a history of short stature. One (or any odd number) crossover within the centromeric segment during meiosis would produce recombinant chromosomes; one with a duplication of the inserted segment and the other a deletion. In this 4-generation family, there were six instances of transmission of the recombinant chromosome with duplication of the11p15.5 segment, which leads to a SRS phenotype when maternally inherited and a Beckwith-Wiedemann phenotype when paternally transmitted. The size of the duplicated region is ~1.9 Mb as determined by microarray analysis. This study provides further evidence that maternally inherited duplications of 11p15.5 result in a SRS phenotype that includes short stature and other variable features. The methylation status of the extra copy of the duplicated region of 11p15.5 ultimately predicts the resulting phenotype. Thus, the different phenotype based on parental mode of transmission is of importance in the genetic counseling of these patients.

Variable levels of tissue mosaicism can confound the interpretation of chromosomal microarray results from peripheral blood

Chromosomal microarray analysis (CMA) has significantly increased the ability to diagnose medical conditions caused by copy-number variation in the human genome. Given that the regions involved in copy-number abnormalities often encompass multiple genes, it has been common practice in recent years to compare the phenotypes of individuals with specific copy-number alterations identified by CMA, with the goal of identifying the critical regions for particular elements of a disease phenotype. It is rarely mentioned that this practice relies heavily on the assumption that the absence of mosaicism on CMA from a peripheral blood sample (the most common source of DNA in current clinical practice) reflects the absence of mosaicism in other tissues. We report here a case that violates that assumption. A 28-year-old male with Charcot–Marie–Tooth disease was found by CMA to have a duplication of 17p12 along with two other abnormalities: A duplication of 12p13.33 translocated to the long arm of chromosome 3 and an interstitial duplication of 12p11.23. The patient did not have any clinical features suggestive of 12p duplication syndrome. Chromosomal microarray analysis on skin fibroblasts revealed the duplications at 17p12 and 12p11.23, but not the terminal duplication of 12p13.33. FISH analysis on skin fibroblasts confirmed the presence of very low levels of mosaicism for the terminal 12p duplication. The case illustrates how the absence of mosaicism in blood is not always indicative of the absence of mosaicism in other tissues. Even in an era of high-throughput, highly accurate DNA-based tests, it is important to remember the limitations of testing before drawing conclusions about the relationship between a test results and a clinical phenotype.

A coalescence of two syndromes in a girl with terminal deletion and inverted duplication of chromosome 5

BackgroundRearrangements involving chromosome 5p often result in two syndromes, Cri-du-chat (CdC) and Trisomy 5p, caused by a deletion and duplication, respectively. The 5p15.2 has been defined as a critical region for CdC syndrome; however, genotype-phenotype studies allowed isolation of particular characteristics such as speech delay, cat-like cry and mental retardation, caused by distinct deletions of 5p. A varied clinical outcome was also observed in patients with Trisomy 5p. Duplications of 5p10-5p13.1 manifest themselves in a more severe phenotype, while trisomy of regions distal to 5p13 mainly causes mild and indistinct features. Combinations of a terminal deletion and inverted duplication of 5p are infrequent in literature. Consequences of these chromosomal rearrangements differ, depending on size of deletion and duplication in particular cases, although authors mainly describe the deletion as the cause of the observed clinical picture.Case presentationHere we present a 5-month-old Slovenian girl, with de novo terminal deletion and inverted duplication of chromosome 5p. Our patient presents features of both CdC and Trisomy 5. The most prominent features observed in our patient are a cat-like cry and severe malformations of the right ear.ConclusionThe cat-like cry, characteristic of CdC syndrome, is noted in our patient despite the fact that the deletion is not fully consistent with previously defined cat-like cry critical region in this syndrome. Features like dolichocephaly, macrocephaly and ear malformations, associated with duplication of the critical region of Trisomy 5p, are also present, although this region has not been rearranged in our case. Therefore, the true meaning of the described chromosomal rearrangements is discussed.

Report on 3 patients with 12p duplication including GRIN2B

The duplication of the short arm (p) of chromosome 12 is a rare chromosomal abnormality, and most reported cases result from malsegregation of a balanced parental translocation associated with other chromosomal imbalances. Of the reported cases, only 15 involve a pure and complete 12p duplication and only 10 involve a pure and partial duplication overlapping the 12p12.3p13.1 region, including a single instance of an inherited duplication in two related individuals. Here, we report three new patients with a pure 12p duplication, detected by conventional cytogenetic studies and characterized by array-comparative genomic hybridization (array-CGH) and fluorescence in situ hybridization (FISH). The first patient was a child carrying a de novo inverted duplication of the short arm of chromosome 12. His phenotype was similar to that of the “trisomy 12p syndrome”, characterized by developmental delays and craniofacial abnormalities including a high forehead, a short nose with anteverted nostrils and an everted lower lip. The second and third patients were a mother and son with a direct 12p12.3p13.1 duplication, exhibiting a milder phenotype characterized by moderate developmental delays, dysmorphic facial features, behavioral problems and obesity. The present data, including the rarity of the familial cases, should contribute to our knowledge of the genotype/phenotype correlation in trisomy 12p patients.

Dilated cardiomyopathy due to a phospholamban duplication

Dilated cardiomyopathy is characterised by dilation and impaired systolic function. We present the case of a child with dilated cardiomyopathy caused by a 624 kb duplication of 6q22.31, which includes the phospholamban gene. The patient also has failure to thrive and developmental delay due to complex cytogenetic abnormalities including a 5p15 deletion associated with Cri du Chat and an 11p15 duplication associated with Russell-Silver syndrome.

Partial trisomy 1q41‐qter and partial trisomy 9pter‐9q21.32 in a newborn infant: An array CGH analysis and review

We report on a girl who presented with distinctive abducted hip and hyperextended knee. Cytogenetic analysis detected an extra derivative chromosome resulting from a balanced translocation in the mother and 3:1 segregation. Using array comparative genomic hybridization (CGH) in combination with conventional high resolution GTG banding, we designate the karyotype as 47, XX, +der(9)t(1;9)(q41;q21.32)mat, indicating tertiary trisomy of chromosome segments 1q41-qter and 9pter-9q21.32. A review and genotype-phenotype correlation suggested that the patient represented most of the manifestations of duplication of chromosome arms 1q and 9p. To our knowledge, a similar case has so far not been reported.

Correct developmental expression level of Rai1 in forebrain neurons is required for control of body weight, activity levels and learning and memory

Potocki-Lupski syndrome (PTLS) is a genomic disorder associated with an ∼3 Mb duplication in 17p11.2. Clinical features include leanness, intellectual disability, autistic features and developmental deficits. RAI1 gene dosage is associated with the PTLS phenotypes. To understand where and when Rai1 overexpression is detrimental, we generated a mouse that over-expresses Rai1 conditionally in forebrain neurons (I-Rai1). Phenotypic characterization of I-Rai1 mice showed significant underweight, hyperactivity and impaired learning and memory ability compared with wild-type littermates. Doxycycline administration can turn off the transgene expression allowing the restoration of Rai1 normal expression levels. When the transgene was turned off from conception to 3 months of age, no phenotypic differences were observed between I-Rai1 and their wild-type littermates. Surprisingly, we found that turning off the transgene expression before the onset of the phenotypes (1-3 months) or after the onset of the phenotypes (3-5 months) cannot prevent nor reverse the phenotypic outcomes. Our results indicate that Rai1 dosage in forebrain neurons is critical during the development and is related to body weight regulation, activity levels and learning and memory.

SNP arrays in Beckwith–Wiedemann syndrome: An improved diagnostic strategy

Beckwith–Wiedemann syndrome is an overgrowth disorder with an increased risk of childhood tumors that results from a dysregulation of imprinted gene expression in the 11p15 region. Since epigenetic defects are the most frequent anomalies, first-line diagnostic methods involve methylation analysis. When paternal isodisomy is suspected, it should be confirmed by a second technique capable of distinguishing true 11p15 paternal disomy (patUPD) from paternal 11p15 duplication or 11p15 trisomy. We sought to evaluate the interest of using SNP arrays in the Beckwith–Wiedemann syndrome diagnostic strategy. We analyzed the SNP profiles of 25 Beckwith Wiedemann patients with previously determined methylation indexes. Among them, 3 had 11p15 trisomies, 13 had patUPD, 8 had an inconclusive methylation index and 1 had a normal result. All known trisomies and known patUPDs were detected. Moreover we found 7 low-rate mosaicisms 11p15 patUPDs among the 8 patients with an inconclusive methylation index. We were able to precisely characterize the sizes and mosaicism rates of the anomalies. We demonstrate that SNP arrays are of real diagnostic interest in Beckwith–Wiedemann syndrome: 1) they help to distinguish patUPDs from trisomies more precisely than karyotyping and FISH, 2) they help determine the size and mosaicism rate of patUPDs, 3) they provide complementary information in inconclusive cases, helping to distinguish low-rate patUPD mosaicism from other BWS-related molecular defects.

Génétique des schizophrénies : mise en perspective des schizophrénies à début précoce et autres pathologies du développement

Schizophrenia (SCZ) is a severe brain disorder characterized by hallucinations, delusions, flat and/or inappropriate affect and cognitive impairment. The lifetime risk is about 0.5% with heritability of 65–85%. The prevalence of early-onset schizophrenia (defined here as before 15 years of age) has not been well studied, but is likely to be 5–10% of all cases. The rarity of early-onset SCZ has made it difficult to study. We focus on genetic studies of adults with schizophrenia, highlighting results for early-onset schizophrenia where available. Prior to the past 5years, studies failed to find replicable association or linkage between SCZ and specific genes when appropriate statistical corrections for multiple testing were used. Many false positive results were probably reported using the candidate gene approach. Recently, the development of single nucleotide polymorphism (SNP) “chips” has permitted large genome-wide association study (GWAS) analyses that suggest that across all age groups, a proportion of genetic risk can be attributed to a large number of common SNP, each with a very small effect on risk (odds ratios of 1.1 or less). The greatest known genetic effect is conferred by the 1.5–3 Mb 22q.11.2 deletions, which occurs in ∼ 1/4000–1/6000 births with SCZ developing in 20–30% of carriers. Large SNP and aCGH microarray studies have now identified associations between SCZ and other rare, large copy number variations (CNV, insertions and deletions) with high odds ratios (5–10), including deletions of 1q21, 2p16.3 (neurexin-1 gene), 3q29 and 15q13.3, and duplications of 16p11.2. Some of these CNV are also associated with autism or other developmental disorders as well as epilepsy or intellectual deficiency, suggesting some overlap in the mechanisms that contribute to risks of these disorders. Based on preliminary data from larger-scale analyses in progress, approximately 1–2% of cases carry a CNV that has been clearly associated with SCZ (ORs 4–12). Whole exome and genome sequencing studies of large adult samples will be the next steps to identify rarer SCZ-associated mutations, including point mutations and smaller as well as rarer CNV. Genetic findings are beginning to contribute to an understanding of biological mechanisms of SCZ risk and may lead to new approaches to treatment.

Stress and Well‐Being Among Parents of Children with Potocki‐Lupski Syndrome

Potocki-Lupski syndrome (PTLS) or duplication 17p11.2 syndrome is a newly characterized condition causing a variety of health problems with variable severity, including failure to thrive in infancy and childhood, hypotonia, structural heart anomalies, cognitive impairments, speech and learning difficulties, and autism. Due to its recent clinical characterization little is known about the psychosocial impact of this condition on patients and their families. This study evaluated whether parental psychosocial outcomes were associated with children's PTLS disease severity. Parents of 58 children with PTLS completed a cross-sectional survey that assessed parental stress, quality of life, and coping skills. Parental functioning was associated with greater severity of feeding difficulty and with lower severity of a cardiovascular defect. Findings from this study highlight potential support needs of parents of children affected by PTLS and suggest ways in which these needs may be addressed.

Prevalence of selected genomic deletions and duplications in a French–Canadian population‐based sample of newborns

Chromosomal microarray analysis has identified many novel microdeletions or microduplications that produce neurodevelopmental disorders with a recognizable clinical phenotype and that are not observed in normal individuals. However, imbalance of other genomic regions is associated with a variable phenotype with intellectual disability (ID) or autism in some individuals but are also observed in completely normal individuals. Several large studies have reported the prevalence of copy number (CN) variants in people with particular features (e.g., ID, autism, schizophrenia, or epilepsy); few studies have investigated the prevalence of genomic CN changes in the general population. We used a high-throughput method to screen 6813 consecutive cord blood samples from a predominantly French–Canadian population to assess genomic CN in five genomic regions: 1p36, 15q11-q13, 16p11.2, 16p11.2-p12.2, and 22q11.2. We identified one deletion and one duplication within 1p36, two deletions of 15q11-q13, eight deletions of 16p11.2-p12.2, two deletions and five duplications of 16p11.2, and six duplications of 22q11.2. This study provides estimates of the frequency of CN variants in an unselected population. Our findings have important implications for genetic counseling.

Generalized Epilepsy in Two Patients with 5p Duplication

There are only few reports on patients with duplications of the short arm of chromosome 5, with little information about concomitant epilepsy. We report on two patients with generalized epilepsies since age 2.5 years, in whom array comparative genomic hybridization revealed microduplications of different sizes in the short arm of chromosome 5. Both patients showed developmental delay, and magnetic resonance images were normal. The larger duplication in patient 1, who additionally exhibited dysmorphic features and photosensivity on electroencephalogram, occurred de novo, whereas the smaller duplication in patient 2 was paternally inherited. The overlapping duplicated region in band 5p13.1 comprises four genes (RICTOR, FYB, C9, and DAB2). Further investigation on patients with duplication 5p and epilepsy are needed to possibly identify a potential susceptibility locus for epilepsy at chromosome 5p13.1.

7q36 deletion and 9p22 duplication: effects of a double imbalance

The etiology of mental retardation/developmental delay (MRDD) remains a challenge to geneticists and clinicians and can be correlated to environmental and genetic factors. Chromosomal aberrations are common causes of moderate to severe mental retardation and may represent 10% of these occurrences. Here we report the case of a boy with development delay, hypoplasia of corpus callosum, microcephaly, muscular hypotonia, and facial dysmorphisms. A deletion of 7q36.1 → 36.3 and duplication of 9p22.3 → 23 was detected as a result of an unbalanced translocation of paternal origin. Breakpoint delimitation was achieved with array comparative genomic hybridization assay. Additional multiplex ligation dependent probe amplification (MLPA) analyzes confirmed one copy loss of 7q36.3 region and one copy gain of 9p24.3 region. Patient resultant phenotype is consistent with the already described findings for both 7q deletion and 9p duplication syndromes.

Clinical Course and Pathological Findings in a Series of Patients with Aggressive Natural Killer (NK) Cell Leukemia

Abstract 4823 Background:NK cell leukemia is a rare, malignant proliferation of NK cells associated with Epstein Barr Virus (EBV). The World Health Organization (WHO) defines NK cell leukemia based on a blood film showing pancytopenia, and circulating leukemic cells, which are positive for CD2, cytoplasmic CD3, CD56, and cytotoxic molecules. The neoplastic cells may have a wide range of appearances, including cells that resemble large granular lymphocytes, highly atypical cells with abundant cytoplasm, and azurophilic granules. Reported cytogenetic abnormalities have included 6q deletion, 11 q deletion and losses of 7p and 17p.Previous publications in the medical literature have been limited to case reports, mostly from Asian centers. Methods:We conducted a retrospective chart review of all aggressive NK cell leukemia diagnoses at an academic medical center, from 2008–2012. Results:We identified 4 cases of aggressive NK cell leukemia. The median age at diagnosis was 57 years. 3 out of 4 cases were male, and 3 of 4 were associated with EBV infection. All patients presented clinically with cytopenias, one patient had an elevated white blood cell count, 31 × 10 9per liter with the others presenting with pancytopenia. All had constitutional symptoms (including fever and night sweats) at diagnosis. 2/4 cases had extramedullary involvement, including splenomegaly and lymphadenopathy. One patient presented with hemophagocytic lymphohistiocytosis. 2/4 patients had CNS involvement. All had a large proportion of circulating neoplastic cells (12–80%).The blood film examination in all cases demonstrated large, pleomorphic neoplastic cells. Most (3/4) had distinct nucleoli and 1/4 had large azurophilic granules in the cytoplasm. The immunohistochemistry profile showed positivity for cytoplasmic CD3, CD56 and CD7 in all cases. 3/4 cases were positive for CD11c. 2/4 patients had unique complex karyotypes including chromosome 3p duplication, deletion of 16q, addition 1p, trisomy 7, trisomy 8, isochrome 17q and near tetraploid karyotype.All patients received treatment with various chemotherapeutic protocols; however none received radiation therapy, or stem cell transplantation. 2/4 cases achieved a short remission. All patients had poor clinical outcomes with median survival of 12 months (range 2–19 months), which is consistent with prior reports. Conclusion:This case series serves to confirm the typical clinical presentation, and poor prognostic outlook, of patients with aggressive NK cell leukemia. This rare malignancy was previously described only in individual case reports. In our patient population, we noted complex, novel cytogenetic findings. Our study reaffirms the need for new therapeutic modalities to improve the poor prognosis for this disease. Disclosures:No relevant conflicts of interest to declare.