Rare Chromosomal Aberration Research Articles

Autopsy findings in a fetus with monosomy 20 mosaicism

Introduction. Mosaic monosomy 20 is a rare chromosomal aberration, without characteristic clinical features. We present a case of a fetus with monosomy 20 mosaicism revealed after prenatal ultrasound detection of anhydramnios and multiple anomalies. Case outline. The second pregnancy of a 33-year-old woman, was terminated at 23rd gestational week, because of the multiple fetal anomalies and anhydramnios, detected by ultrasound. The autopsy of a female fetus revealed multiple congenital anomalies: ventriculomegaly, bilateral choroid plexus cysts, perivascular gliosis in periventricular region of cerebri, hydropericardium, severe cardiomegaly, severe myocardial hypertrophy, hydrothorax, glandular/canalicular stage of fetal lung development, bilateral renal and ureter agenesis (Potter syndrome), bladder aplasia, agenesis of the uterus, fallopian tubes and proximal vagina and valgus deformity of left foot (pes valgus). Fetal growth was adequate for gestational age with no craniofacial dysmorphia or radiographically visible anomalies of the skeleton, without signs of infection. The umbilical cord was too long for gestational age ? 48 cm. Analysis of fetal karyotype from fetal blood sampling revealed monosomy of chromosome 20 in 10% of analyzed cells in metaphase. Conclusion. Revealing the genetic basis of fetal anomalies is at outmost importance not only for further evaluation of pregnancy, but also for proper genetic informing of patients.

Familial 5.29 Mb deletion in chromosome Xq22.1–q22.3 with a normal phenotype: a rare pedigree and literature review

BackgroundXq22.1–q22.3 deletion is a rare chromosome aberration. The purpose of this study was to identify the correlation between the phenotype and genotype of chromosome Xq22.1–q22.3 deletions.MethodsChromosome aberrations were identified by copy number variation sequencing (CNV-seq) technology and karyotype analysis. Furthermore, we reviewed patients with Xq22.1–q22.3 deletions or a deletion partially overlapping this region to highlight the rare condition and analyse the genotype–phenotype correlations.ResultsWe described a female foetus who is the “proband” of a Chinese pedigree and carries a heterozygous 5.29 Mb deletion (GRCh37: chrX: 100,460,000–105,740,000) in chromosome Xq22.1–q22.3, which may affect 98 genes from DRP2 to NAP1L4P2. This deletion encompasses 7 known morbid genes: TIMM8A, BTK, GLA, HNRNPH2, GPRASP2, PLP1, and SERPINA7. In addition, the parents have a normal phenotype and are of normal intelligence. The paternal genotype is normal. The mother carries the same deletion in the X chromosome. These results indicate that the foetus inherited this CNV from her mother. Moreover, two more healthy female family members were identified to carry the same CNV deletion through pedigree analysis according to the next-generation sequencing (NGS) results. To our knowledge, this family is the first pedigree to have the largest reported deletion of Xq22.1–q22.3 but to have a normal phenotype with normal intelligence.ConclusionsOur findings further improve the understanding of the genotype–phenotype correlations of chromosome Xq22.1–q22.3 deletions.This report may provide novel information for prenatal diagnosis and genetic counselling for patients who carry similar chromosome abnormalities.

Hypergonadotropic hypogonadism and chromosomal aberrations: clinical heterogeneity and implications on the health of elderly men, case series

BackgroundHypogonadism in older men is often considered as late onset hypogonadism. However, this clinical condition results from primary testicular failure which could be of genetic origin with Klinefelter syndrome being the most common chromosomal abnormality associated with it.Case presentationWe report a heterogeneous group of cases who were diagnosed with hypergonadotropic hypogonadism in their adulthood and were found to have rare chromosomal aberrations. All were elderly men (in their 70 s and 80 s) for whom the diagnosis was made during the evaluation of incidental symptoms suggestive of endocrinopathy. The first had hyponatremia; the other two had gynaecomastia and features of hypogonadism noted during admission for various acute medical problems. With respect to their genetic results; the first had a male karyotype with balanced reciprocal translocation between the long arm of chromosome 4 and the short arm of chromosome 7. The second case had a male karotype with one normal X chromosome and an isochrome for the short arm of the Y chromosome. The third case was an XX male with unbalanced translocation between the X & Y chromosomes with retention of the SRY locus.ConclusionHypergonadotrophic hypogonadism in the elderly, may be due to chromosomal aberrations, resulting in heterogeneous and diverse clinical phenotypes. Vigilance must be exercised when seeing cases with subtle clinical findings. This report suggests that in selected cases of adult hypergonadotropic hypogonadism, chromosomal analysis may be indicated.

Abstract 2053: Structural variants detected by optical genome mapping in acute lymphoblastic leukemia patient-derived xenografts models

Abstract Background: The established classification of acute lymphoblastic leukemia (ALL) does not cover all high-risk patients because of the difficulty in detecting novel or rare structural variants (SVs). Furthermore, many SVs and formed gene fusions have adverse prognostic effects on hematological malignancies. This study aims to investigate SVs in 22 patient-derived xenografts (PDX) of ALL and to assess rare SVs and chromosomal aberrations, particularly hematological malignancy genes and gene fusions in different individuals detected by optical genome mapping (OGM). Methods: Leukemia cells from 16 patients with B-cell precursor acute lymphoblastic leukemia (B-ALL) and 6 patients with T-cell acute lymphoblastic leukemia (T-ALL) were inoculated into immuno-deficient mice, growth curves were monitored, and leukemia cells were collected after human CD45 was more than 80%. OGM (Bionano Genomics), RNA sequencing (RNA-seq) and whole genome sequencing (WGS) techniques were used to detect SVs and gene fusions. In validation, polymerase chain reaction (PCR) and fluorescence in situ hybridization (FISH) tests were performed to identify specific SVs. Results: On average, each model detected 42 rare SVs with known overlapping genes in different types by OGM: 12 insertions, 25 deletions, 1 inversion, 3 duplications, 2 inter-chromosomal translocations and 1 intra-chromosomal translocation. 5 rare SVs were found in multiple models (>=5), and two of them were never reported in B-ALL and T-ALL. Gene fusions were detected in all ALL models by OGM, and 17% were novel fusions. At the mRNA level, gene fusions were detected only in 19 models, and 24% of the predicted gene fusions by OGM were identical to the results of RNA-seq (high confidence results including pseudogenes). These two technologies could detect different fusion partners. For example, MLLT1 was seen at the mRNA level, and ACER1 was detected at the DNA level in the same KMT2A rearrangement model. Of the 16 B-ALL models, 6 were p190 BCR-ABL1 (a fusion of BCR exon 1 and ABL1 exon 2), 1 was p210 BCR-ABL1 (a fusion of BCR exon 13 and ABL1 exon 2) and 5 of 7 had IKZF1 gene deletions. 2 p190 BCR-ABL1 models were insensitive to imatinib and 2 p190 BCR-ABL1 models as well as the model with IKZF1 exons 4-7 deletion were sensitive to imatinib when treatment was initiated early in the disease. A novel ARL15-IKZF1 fusion was identified in one of the sensitive models. Deletion of the PRKAR2B gene was another rare SV in both models sensitive to imatinib besides the IKZF1 deletion. Conclusion: OGM assays were more comprehensive, and novel rare SVs were identified in ALL. Combining the results of gene fusions between different technologies will provide more accurate predictions for ALL classifications. The combination of aberrant SVs may synergize to influence the efficacy of imatinib, which warrants further investigations. Citation Format: Yueying Wang, Mengting Qin, JinPing Liu, Xiaobo Chen, Jia Xue, Sheng Guo. Structural variants detected by optical genome mapping in acute lymphoblastic leukemia patient-derived xenografts models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2053.

Cases of tetrasomy 9p and trisomy 9p in prenatal diagnosis-Analysis of noninvasive and invasive test results.

Objective: Tetrasomy 9p and trisomy 9p are rare chromosomal aberrations. The phenotypes of tetrasomy 9p and trisomy 9p are variable. Most cases are diagnosed in the postnatal period. The study aims to analyze the prenatal phenotype of tetrasomy 9p and trisomy 9p in terms of ultrasound and screening tests. Methods: A set of 1573 prenatal tests performed from 2016 to 2021 was reviewed to identify all cases with trisomy 9p and tetrasomy 9p. In four cases with 9p gain, non-invasive and invasive test results were analyzed. Results: Four cases with the 9p gain were diagnosed in the prenatal period: two cases with tetrasomy 9p and two cases with trisomy 9p. Nasal bone hypoplasia and ventriculomegaly are common features of 9p gain. In two out of four cases with the 9p gain, an increased risk of trisomy 21 was found in the combined first-trimester screening test. Conclusion: Trisomy 9p and tetrasomy 9p are characterized by a variable phenotype in the prenatal period, manifesting in genetically abnormal fetuses. The tetrasomy 9p and trisomy 9p may suggest trisomy 21 in the first trimester.

Myeloid malignancies with translocation t(4;12)(q11-13;p13): molecular landscape, clonal hierarchy and clinical outcomes.

Translocation t(4;12)(q11‐13;p13) is a recurrent but very rare chromosomal aberration in acute myeloid leukaemia (AML) resulting in the non‐constant expression of a CHIC2/ETV6 fusion transcript. We report clinico‐biological features, molecular characteristics and outcomes of 21 cases of t(4;12) including 19 AML and two myelodysplastic syndromes (MDS). Median age at the time of t(4;12) was 78 years (range, 56–88). Multilineage dysplasia was described in 10 of 19 (53%) AML cases and CD7 and/or CD56 expression in 90%. FISH analyses identified ETV6 and CHIC2 region rearrangements in respectively 18 of 18 and 15 of 17 studied cases. The t(4;12) was the sole cytogenetic abnormality in 48% of cases. The most frequent associated mutated genes were ASXL1 (n = 8/16, 50%), IDH1/2 (n = 7/16, 44%), SRSF2 (n = 5/16, 31%) and RUNX1 (n = 4/16, 25%). Interestingly, concurrent FISH and molecular analyses showed that t(4;12) can be, but not always, a founding oncogenic event. Median OS was 7.8 months for the entire cohort. In the 16 of 21 patients (76%) who received antitumoral treatment, overall response and first complete remission rates were 37% and 31%, respectively. Median progression‐free survival in responders was 13.7 months. Finally, t(4;12) cases harboured many characteristics of AML with myelodysplasia‐related changes (multilineage dysplasia, MDS‐related cytogenetic abnormalities, frequent ASXL1 mutations) and a poor prognosis.

The significance of rare chromosomal abnormalities and fetoplacental mosaicism in prenatal diagnosis in the non-invasive prenatal testing era

To determine the prevalence of microscopically visible de novo atypical chromosomal aberrations and fetoplacental mosaicism in a prenatal tertial referral center, and to investigate the maternal and fetal characteristics in connection with genomewide non-invasive prenatal screening. Retrospective cohort study from 2014 to 2019 of pregnancies with invasive genetic analysis. In the cohort of 2504 cases, the proportion of CVS was 53.3%. We diagnosed 200 chromosomal aberrations (8%), including 13.5% of de novo rare chromosomal aberrations (14 rare autosomal trisomies, 6 polyploidies, 5 structural aberrations and 2 small supernumerary marker chromosomes). The rate of fetoplacental mosaicism was 12.4%/77.8% in common/atypical chromosomal aberrations (p = 0.001) and confined to placenta in 17/40 cases. Associated ultrasound abnormalities were abnormal nuchal translucency and major malformations in 58% and 35% with common trisomies and 11% (p = 0.006) and 67% (p = 0.047) with true mosaic cases of rare abnormalities, respectively. Major ultrasound malformation was facial dysmorphism with rare aberrations. Potential application of genomewide non-invasive prenatal test in atypical chromosomal aberrations presumably would have been false-positive in 12 cases (44%), false-negative in 1 case (3.7%), and would have early detected 2 cases of rare autosomal trisomies (7.4%) without ultrasound anomalies. Structural ultrasound malformations with normal nuchal translucency thickness may be indicative of rare chromosomal aberrations. Application of genomewide non-invasive prenatal test is an alternative of early diagnostic methods with a potential of discordant results due to mosaicism. Knowledge about the presence of fetoplacental mosaicism influences risk estimation and genetic counseling, detailed cytogenetic characterization is of utmost importance. Orv Hetil. 2021; 162(29): 1156-1165.

Rare chromosomal aberrations detected in children with multiple congenital anomalies: utility of multiple ligation dependant probe amplification for developing countries

Chromosomal aberrations are an important cause of multiple malformation syndromes. Multiple ligation-dependent probe amplification (MLPA) a molecular cytogenetic technique has been suggested as a screening tool for the detection of chromosomal aberrations in resource-limited settings. MLPA can detect chromosomal microdeletions or duplications at approximately 40 chromosomal regions in a single experiment. Several MLPA kits are available to target the chromosomal regions of interest. In the present study, we aimed to detect the yield and utility of MLPA in a cohort of children with multiple malformations and developmental delay. MLPA was performed using kits P245, P070 and P036. The overall yield of MLPA in our cohort was 8%. The manuscript describes very rare and interesting cases of congenital anomalies, such as severe buphthalmos and biphalangeal fingers with a chromosomal etiology. The study demonstrates the usefulness of MLPA as screening technique for chromosomal aberrations in children with multiple malformation syndromes, especially for developing countries such as India.

Reduced anogenital distance, hematuria and left renal hypoplasia in a patient with 13q33.1\u201334 deletion: case report and literature review

Background13q33–q34 microdeletions are rare chromosomal aberrations associated with a high risk of developmental disability, facial dysmorphism, cardiac defects and other malformation of organs. It is necessary to collect and report evidence of this rare chromosome mutation to improve the prognosis of this rare disease.Case presentationWe report a patient harboring an 11.56 Mb microdeletion at 13q33.1–34 region, which contains about 30 OMIM genes. Besides the common clinical manifestations such as facial dysmorphism, developmental delay, intellectual disability, epilepsy, and congenital heart disease, she also suffered from a reduced anogenital distance, hematuria and left renal hypoplasia. Most related cases were characterized by facial deformity and heart defects, but there were few reports on renal malformation, especially regarding renal hypoplasia with hematuria.ConclusionWe have reported a patient suffering from a reduced anogenital distance, hematuria and left renal hypoplasia. A de novo 11.56 Mb deletion ranging from 13q33.1 to 13q34 (Chr13:103542220–115,106,996) was found by SNP-array analysis. It might be the first time for hematuria and renal hypoplasia to be reported as symptoms of 13q33-q34 deletion syndrome Neurodevelopmental disability, heart defects and urogenital/anorectal anomalies may be resulted from common or overlapping regions of deletion in chromosome bands 13q33.1-q34 and may share a common molecular mechanism.

Bir Rekombinant Kromozom 4 Olgusunun Klinik Özelliklerinin Ayrıntılı Tanımlanması

Recombinant chromosome 4 is a very rare chromosomal aberration with eleven cases reported in the literature up to date. Here we report a five years old male patient with de novo rec(4) dup(4p) del(4q). The physical examination findings were as follows: caput quadratum, flat occiput, low frontal hairline, hypertelorism, ptosis, blepharophimosis, high arched eyebrows, flat nasal root with antevert nostrils and short nose, long and smooth philtrum, thin upper lip with triangular mouth, high arched palate, dental anomalies, large low-set ears, short neck, broad chest with widely spaced nipples, micropenis, cryptorchidism. Conventional cytogenetic analysis revealed the karyotype as 46,XY,rec(4)dup(4p14p16.3)del(4q34.3q35). Flourescence in-situ hybridization (FISH) analysis with sub-telomeric probes for 4p and 4q showed duplication of 4p and deletion of 4q in recombinant chromosome 4. His parents’ chromosomal analysis and sub-telomeric FISH analysis were both normal. The patient’s final karyotype was reported as 46,XY,rec(4)dup(4p16.3p14)del(4q34.4q35).arr[hg19]4p16.3p14(68,345-36,018)x3,4q34.3q35(177,676,319-190,957,460)x1 detected by Microarray. According the literature all cases with recombinant chromosome 4 have similar clinical findings. Except for our case only one case in the literature has been reported to be de novo . In conclusion, we reported a very rare case of recombinant chromosome 4, which has the largest deletion and duplication in the literature. Further cases with similar findings would help delineation of the symptoms related to the aberration.

Can cell-free DNA testing be used in pregnancies with isolated fetal omphalocele? Preliminary evidence from cytogenetic results of prenatal cases

Objective: To evaluate whether cell-free DNA (cfDNA) testing could replace an invasive procedure in pregnancies with isolated fetal omphalocele.Study design: This was a retrospective study of all pregnancies with sonographically detected fetal omphalocele at three tertiary referral centers between 2012 and 2016. Invasive diagnostic testing was performed for genetic investigations using conventional karyotyping or chromosomal microarray. cfDNA testing was assumed to be offered to patients with isolated fetal omphalocele for screening for common aneuploidies.Results: Invasive genetic testing was performed in a total of 107 pregnancies with a fetal omphalocele. Abnormal karyotype was found in 66% (31/47) of nonisolated omphalocele cases and in 1.7% (1/60) of isolated omphalocele cases. No pathogenic copy number variations (CNVs) were detected in 59 cases with isolated omphalocele and normal karyotype. If cfDNA screening was used in cases with isolated omphalocele, the affected fetus with trisomy 18 would be detected, and no rare chromosomal aberrations or submicroscopic pathogenic CNVs would be missed.Conclusions: cfDNA testing could be recommended for prenatal genetic evaluation in pregnancies with isolated fetal omphalocele after thorough pretest counseling.Key Message: A very low percentage of aneuploidies and rare chromosomal/subchromosomal abnormalities are found in prenatal cases of isolated omphalocele. It seems that for pregnancies with isolated omphalocele, cfDNA testing represents an alternative for patients who choose to continue the pregnancies and are reluctant to undertake invasive diagnostic testing.

Impact of Additional Chromosomal Aberrations on the Disease Progression of Chronic Myelogenous Leukemia.

The emergence of additional chromosomal abnormalities (ACAs) in Philadelphia chromosome/BCR-ABL1 positive chronic myeloid leukemia (CML), is considered to be a feature of disease evolution. However, their frequency of incidence, impact on prognosis and treatment response effect in CML is not conclusive. In the present study, we performed a chromosome analysis of 489 patients in different clinical stages of CML, using conventional GTG-banding, Fluorescent in situ Hybridization and Spectral Karyotyping. Among the de novo CP cases, ACAs were observed in 30 patients (10.20%) with lowest incidence, followed by IM resistant CP (16.66%) whereas in AP and BC, the occurrence of ACAs were higher, and was about 40.63 and 50.98%, respectively. The frequency of occurrence of ACAs were compared between the study groups and it was found that the incidence of ACAs was higher in BC compared to de novo and IM resistant CP cases. Likewise, it was higher in AP patients when compared between de novo and IM resistant CP cases, mirroring the fact of cytogenetic evolution with disease progression in CML. In addition, we observed 10 novel and 10 rare chromosomal aberrations among the study subjects. This study pinpoints the fact that the genome of advanced phase patients was highly unstable, and this environment of genomic instability is responsible for the high occurrence of ACAs. Treatment response analysis revealed that compared to initial phases, ACAs were associated with an adverse prognostic effect during the progressive stages of CML. This study further portrayed the cytogenetic mechanism of disease evolution in CML.

Isochromosome der(17)(q10)t(15;17) in acute promyelocytic leukemia resulting in an additional copy of the RARA-PML and loss of one p53 gene: Report of two cases and literature review

Introduction. The isochromosome of the long arm of derivative chromosome 17, that originates from the translocation t(15;17) [ider(17)(q10)t(15;17), or ider(17q)] in acute promyelocytic leukemia (APL), is a rare chromosome aberration associated with a poor prognosis. Case report. We report the clinical and laboratory data associated with ider(17q) for two APL patients. Cytogenetic analysis of bone marrow cells in both cases showed a mosaic karyotype with the ider(17q); reverse transcription polymerase chain reaction (RT-PCR) was positive for the long (L) isoform of the retionic acid receptor alpha (PML-RARA) fusion transcript in each patient. Fluorescence in situ hybridization (FISH) analysis with the DNA probes for the PML gene on 15q24.1, and the RARA gene on 17q21.2, confirmed the extra copy of the RARA-PML fusion gene or ider(17q). Additionally, the FISH analysis with a DNA probe for the p53 gene on 17p13.1 confirmed loss of one copy of the universal tumor suppressor p53 in both patients. Conclusion. Both reported APL patients with ider(17q) had predominance of the clone with ider(17q) compared to those with t(15;17) and/or the normal karyotype, indicating that duplication of der(17) may provide a growth advantage allowing the relevant clone to become dominant. Moreover, as an important oncogenic event and poor prognostic factor in leukemia, loss of one gene copy of the tumor suppressor p53, may also contribute to this growth advantage. Although the clinical and prognostic significance for the patients with an ider(17q) remains unclear, cytogenetic and molecular-genetic analysis should be combined to reveal more details about this complex and rare chromosomal abnormality.

EP07.02: First trimester ultrasound findings for detecting rare chromosomal aberrations

EP07.02: First trimester ultrasound findings for detecting rare chromosomal aberrations

A balanced translocation disrupting SCN5A in a family with Brugada syndrome and sudden cardiac death

Brugada syndrome (BrS) is a primary arrhythmia syndrome affecting 1 in 2000 of the general population. Genetic testing identifies pathogenic variants in the sodium voltage-gated channel α-subunit 5 gene (SCN5A) in up to 25% of familial BrS. Balanced translocations, which involve the exchange of the ends of 2 different chromosomes, are found in approximately 1 in 500 people. They usually are benign and only rarely are reported to cause arrhythmogenic disorders. The purpose of this study was to identify the genetic mechanism underlying a family with BrS, sick sinus syndrome, cardiac hypertrophy, sudden cardiac death, and multiple miscarriages. We clinically evaluated family members with an electrocardiogram, 2-dimensional echocardiogram, and provocation testing with ajmaline challenge. Cytogenetic testing included karyotype and fluorescent in situ hybridization (FISH) analysis. We performed gene panel, exome, and genome sequencing analysis. Sequencing of 128 cardiac genes and exome sequencing of a family with BrS, sick sinus syndrome, cardiac hypertrophy, sudden cardiac death, and multiple miscarriages did not reveal a pathogenic variant. Karyotype and FISH analysis identified a balanced translocation breaking the SCN5A gene on chromosome 3 and the multiple chromosome maintenance 10 gene (MCM10) on chromosome 10 t(3;10)(p22.2;p13). We characterized both translocation breakpoint junctions using genome sequencing and found no regions of sequence homology. A balanced translocation breaking SCN5A is a novel mechanism underlying disease in a family with BrS, sick sinus syndrome, cardiac hypertrophy, and sudden cardiac death. Genome sequencing can identify rare chromosomal aberrations causing inherited diseases that may otherwise be missed using gene panel and exome sequencing-based approaches.

Prenatal diagnosis of ring chromosome 13: a rare chromosomal aberration

Abstract We report the case of a 24-year-old Japanese woman, gravida 2, para 1, who became pregnant spontaneously. At 24 weeks of gestation, her fetus was found to have various abnormalities, including holoprosencephaly, congenital heart disease and severe fetal growth restriction, and she was referred to our hospital. From these findings, the fetus was suspected of having a chromosomal aberration, in particular, trisomy 13, and after genetic counseling, amniocentesis for chromosomal analysis was performed. Although the results of fluorescent in situ hybridization (FISH) analysis showed no numeric abnormalities, G-banding analysis revealed a ring chromosome 13; 46, XX, r (13) (p13q32). At 41 weeks of gestation, she delivered a female baby weighing 2240 g with good condition. The respiratory status of the neonate was stable, and she was discharged 30 days after birth. Ring chromosomes are rare chromosomal aberrations, and obstetricians should recognize that ring chromosomes cannot be detected solely by FISH analysis and require G-banding analysis and that information on the ring breakpoint is needed to counsel the parents regarding the fetal and neonatal prognosis.

A boy with developmental delay and mosaic supernumerary inv dup(5)(p15.33p15.1) leading to distal 5p tetrasomy \u2013 case report and review of the literature

BackgroundWith only 11 patients reported, 5p tetrasomy belongs to rare postnatal findings. Most cases are due to small supernumerary marker chromosomes (sSMCs) or isochromosomes. The patients share common but unspecific symptoms such as developmental delay, seizures, ventriculomegaly, hypotonia, and fifth finger clinodactyly. Simple interstitial duplications leading to trisomies of parts of 5p are much more frequent and better described. Duplications encompassing 5p13.2 cause a defined syndrome with macrocephaly, distinct facial phenotype, heart defects, talipes equinovarus, feeding difficulties, respiratory distress and anomalies of the central nervous system, developmental delay and hypotonia.Case presentationWe present a boy with dysmorphic features, developmental delay, intellectual disability and congenital anomalies, and a mosaic sSMC inv dup(5)(p15.33p15.1). He is the fourth and the oldest reported patient with distal 5p tetrasomy. His level of mosaicism was significantly different in lymphocytes (13.2%) and buccal cells (64.7%). The amplification in our patient is smaller than that in the three previously published patients but the only phenotype difference is the absence of seizures in our patient.ConclusionsOur observations indicate that for the assessment of prognosis, especially with respect to intellectual functioning, the level of mosaicism could be more important than the extent of amplification and the number of extra copies. Evaluation of the phenotypical effect of rare chromosomal aberrations is challenging and each additional case is valuable for refinement of the genotype-phenotype correlation. Moreover, our patient demonstrates that if the phenotype is severe and if the level of sSMC mosaicism is low in lymphocytes, other tissues should be tested.

Isochromosome 6(p) is a rare chromosomal aberration in Acute Lymphoblastic Leukemia: A case report

Cytogenetic analysis using G- banding technique was performed on bone marrow cells from a 22-year-old female who was diagnosed with Acute Lymphoblastic Leukemia . The chromosomal analysis showed a complex karyotype which included the Isochromosome 6(p) in 16 metaphases (16%) of 97 total metaphases studied . This finding suggests a strong selective pressure for loss of heterozygosity of genes located on 6q , and is in keeping with the hypothesis that one or more tumor suppressor genes might be located on the long arm of chromosome 6 . Moreover, trisomy (or tebasomy) for the short arm of chromosome 6, due to the isochromosome formation , indicating also a possible role for amplification of genes located on 6p in tumor progression in this case of acute lymphoblastic leukemia

The smallest de novo 20q11.2 microdeletion causing intellectual disability and dysmorphic features

The 20q11.2 microdeletion is a rare chromosomal aberration characterized by intellectual disability (ID), motor developmental delay, neonatal feeding problems, and facial dysmorphism. Here, a 2-year- and 6-month-old Japanese girl with a 1.2 Mb microdeletion of 20q11.2 showed ID, motor developmental delay, and distinctive facial features without feeding problems. The deleted region was identified by array-based comparative genomic hybridization and is the smallest reported for a 20q11.2 microdeletion.

Chromosome Structural Alteration an Unusual Abnormality Characterizing Human Neoplasia

Background and Aim: Ring chromosomes are rare cytogenetic abnormalities that occur in less than 10% of hematopoietic malignancies. They are rare in blood disorder. The present review has focused on the ring chromosome associated with oncology malignancies. Materials and Methods: By reviewing the web-based search for all English scientific peer review articles published, was initiated using Medline/PubMed, Mitelman database ( http://cgap.nci.nih.gov/Chromosomes/Mitelman ), and other pertinent references on websites about ring chromosomes in Oncology. The software program as End Note was used to handle the proper references for instruction to author. Karyotype descriptions were cited according to ISCN. Conclusion: Ring chromosomes are rare chromosomal aberrations, almost many times are of de novo origin, presenting a different phenotype regarding the loss of genetic material. The karyotype represents the main analysis for detection of ring chromosomes, but other molecular technics are necessary for complete characterization. The information of this review article adds to the spectrum of both morphology and genetic rearrangements in the field of oncology malignancies.