Genetic counseling of mosaic and non-mosaic tetrasomy 9p at prenatal diagnosis.

Genetic counseling of mosaic and non-mosaic tetrasomy 9p remains difficult because of the possible associated congenital abnormalities, cytogenetic discrepancy in various tissues, true-positive and false-positive diagnosis in non-invasive prenatal testing (NIPT), uniparental disomy (UPD) 9, tissue-limited mosaicism, perinatal progressive decrease of the aneuploid cell line, phenotypic normal carriers and possible favorable fetal outcome in the cases with mosaic tetrasomy 9p at amniocentesis. This article presents a comprehensive review of various counseling issues concerning mosaic and non-mosaic tetrasomy 9p at prenatal diagnosis, and the information provided is very useful for genetic counseling under such circumstances.

Discordant Prenatal Cell-Free DNA Screening vs. Diagnostic Results of Sex Chromosome Aneuploidies: Implications for Newborn Screening and Genetic Counseling.

Sex chromosome aneuploidies (SCAs) collectively occur in 1 in 500 livebirths, and diagnoses in the neonatal period are increasing with advancements in prenatal and early genetic testing. Inevitably, SCA will be identified on either routine prenatal or newborn screening in the near future. Tetrasomy SCAs are rare, manifesting more significant phenotypes compared to trisomies. Prenatal cell-free DNA (cfDNA) screening has been demonstrated to have relatively poor positive predictive values (PPV) in SCAs, directing genetic counseling discussions towards false-positive likelihood rather than thoroughly addressing all possible outcomes and phenotypes, respectively. The eXtraordinarY Babies study is a natural history study of children prenatally identified with SCAs, and it developed a longitudinal data resource and common data elements with the Newborn Screening Translational Research Network (NBSTRN). A review of cfDNA and diagnostic reports from participants identified a higher than anticipated rate of discordance. The aims of this project are to (1) compare our findings to outcomes from a regional clinical cytogenetic laboratory and (2) describe discordant outcomes from both samples. Twenty-one (10%), and seven (8.3%) cases were found to be discordant between cfDNA (result or indication reported to lab) and diagnosis for the Babies Study and regional laboratory, respectively. Discordant results represented six distinct discordance categories when comparing cfDNA to diagnostic results, with the largest groups being Trisomy cfDNA vs. Tetrasomy diagnosis (66.7% of discordance in eXtraordinarY Babies study) and Mosaicism (57.1% in regional laboratory). Traditional genetic counseling for SCA-related cfDNA results is inadequate given a high degree of discordance that jeopardizes the accuracy of the information discussed and informed decision making following prenatal genetic counseling.

A Rare Concurrence of Myelodysplastic Neoplasia and Tetrasomy 8 in a 3-Year-Old Bahraini Male.

Myelodysplastic neoplasia (MDS) is a group of stem cell disorders involving ineffective hematopoiesis. It can be associated with an increased risk of progression toward acute myeloid leukemia (AML). In Bahrain, MDS is the fifth most common primary hematologic malignancy. MDS has an annual incidence of up to 4 million cases. Some of the presenting signs and symptoms of MDS are often nonspecific, such as fatigue, pallor, malaise, fevers, bleeding, bruising, weight loss, and anorexia. Approximately 40% of patients with MDS progress to AML. This paper outlines a case of a 3-year-old Bahraini male (known to have sickle cell trait) who presented to the emergency department of Salmaniya Medical Complex with a five-day history of fever, congested throat, left ear pain, and abdominal pain. He had one episode of vomiting gastric content the previous day. He had previously gone to a private clinic with similar symptoms. Physical examination revealed a short neck and short stature, which was found to be below the 5th percentile. He had generalized pallor and hepatosplenomegaly. A blood smear showed leukopenia and normochromic normocytic anemia. There were excessive blasts found which consisted of 17% of nucleated cells and few granulopoietic cells. Erythropoiesis was active with a few showing mild megaloblastic changes. There were rare megakaryocytes noted. Moreover, the bone marrow aspirate showed two populations on dim CD45. The first population consisted of 3.15% on dim CD45 comprising of hematogones which brightly expressed CD19, HLA-DR, CD79a, and dim CD10. The second population consisted of 14.85% on dim CD45 which expressed CD34, CD13, CD117, HLA-DR, and dim CD7. Based on the peripheral blood smear and bone marrow immunophenotyping findings, a diagnosis of myelodysplastic syndrome with excessive blasts was made, which soon transformed into a diagnosis of AML. Furthermore, increased levels of dysplastic changes and percentage of blasts in the peripheral blood smear and bone marrow lead to a higher possibility of transformation into AML. As per the WHO classification, a diagnosis of MDS needs evaluation of the morphology of blood and bone marrow.

Co-Occurrence of Pallister-Killian Syndrome and Burkitt Lymphoma in a Patient with Near-Normal Neurocognitive Development.

Background: Pallister-Killian syndrome (PKS) is typically recognized by its features that include developmental delay, seizures, sparse temporal hair, and facial dysmorphisms. PKS is most frequently caused by mosaic supernumerary isochromosome 12p. Case Presentation: Here, we report a patient with PKS who was subsequently diagnosed with Burkitt lymphoma. Following the successful treatment of lymphoma, this patient demonstrated very mild intellectual disability despite the diagnosis of PKS, which is usually associated with severe developmental delay. Discussion: This is the first reported patient with PKS and a hematologic malignancy. Although there is no significant reported association of tetrasomy 12p with cancer, the co-occurrence of two rare findings in this patient suggests a potential relationship. The localization of AICDA, a gene for which overexpression has been implicated in promoting t(8;14) noted in our patient's lymphoma, raises a potential mechanism of pathogenesis. In addition, this case indicates that children with PKS can demonstrate near-normal cognitive development.

Prenatal diagnosis of a case with complete and uniform tetrasomy 12p by the utility of noninvasive prenatal testing.

PURPOSE: To report a rare type of Pallister-Killian syndrome (PKS) diagnosed prenatally by the utility of non-invasive prenatal testing (NIPT). METHODS: NIPT was performed in the first trimester. Conventional karyotyping and chromosomal microarray analysis (CMA) were performed on the amniotic samples in the second trimester. Copy number variation sequencing (CNV-seq) was used for the validation of fetal skin and the placental tissue after pregnancy termination. RESULTS: NIPT results showed increased signal from chromosome 12p. Subsequent prenatal diagnostic testing by karyotype revealed 47, XY, +i (12p), and CMA displayed four copies of 12p: 12p13.33-12p11.1(173786_34835641) × 4. The CNV-seq results of the fetal skin and the fetal side of placenta showed four copies of 12p13.33-p11 and an estimated chimeric duplication of 34.08 Mb (chimerism ratio: 10%) in 12 p13.33-p11, respectively. However, no abnormality was detected by CNV-seq at the maternal side of placenta. CONCLUSIONS: Our findings suggest that a positive signal from chromosome 12p on NIPT should raise suspicion for PKS. With the wide application of NIPT, the true positive of incidental finding is expected to increase.

A Chinese family with cat eye syndrome and abnormality of eye movement: First case report.

Background: Cat eye syndrome (CES) is a rare disease with a wide spectrum of phenotypic variability that is observed in 1:150,000 newborns. CES is characterized clinically by the combination of iris coloboma, anal atresia, and preauricular tags and/or pits. Many eye malformations have been reported to be associated with CES, such as iris and chorioretinal coloboma. However, an abnormality of eye movement has not been previously reported. Case presentation: We report on a Chinese family carrying a 22q11.1-q11.21 duplication of 1.7Mb tetrasomy (chr22:16,500,000-18,200,000, hg38) in two generations. Based on the proband and her father's clinical manifestations, including ophthalmological examination, cytogenetic analysis, FISH, CNV-seq, and WES, the diagnosis of CES with an abnormality of eye movement was made. Conclusion: Our findings broadened the symptom spectrum of CES syndrome and laid the foundation for pathogenesis, diagnostic targets, and drug research on the abnormality of eye movement, and were helpful for early diagnosis and intervention of CES.

Mosaic tetrasomy 9p at amniocentesis in a pregnancy associated with a favorable fetal outcome, perinatal progressive decrease of the aneuploid cell line and cytogenetic discrepancy in various tissues.

OBJECTIVE: We present mosaic tetrasomy 9p at amniocentesis in a pregnancy associated with a favorable fetal outcome, perinatal progressive decrease of the aneuploid cell line and cytogenetic discrepancy in various tissue. CASE REPORT: A 33-year-old primigravid woman underwent elective amniocentesis at 18 weeks of gestation because of anxiety, and the karyotype of cultured amniocytes was 47,XX,+i (9) (p10)[20]/46,XX [55]. Cordocentesis was performed at 20 weeks of gestation, and the karyotype of cord blood was 47,XX,+i (9) (p10)[7]/46,XX [15]. She was referred for genetic counseling at 23 weeks of gestation, and repeat amniocentesis revealed a karyotype of 47,XX,+i (9) (p10)[1]/46,XX [16] with seven cells in one colony having tetrasomy 9p in cultured amniocytes, and in uncultured amniocytes, quantitative fluorescence polymerase chain reaction (QF-PCR) analysis excluded uniparental disomy (UPD) 9 and determined paternal origin of the extra i (9p), array comparative genomic hybridization (aCGH) analysis on the DNA extracted from uncultured amniocytes revealed arr 9p24.3p13.1 × 3.0 consistent with 50% mosaicism for tetrasomy 9p, and interphase fluorescence in situ hybridization (FISH) on uncultured amniocytes showed 22.6% (12/53 cells) mosaicism for tetrasomy 9p. A third amniocentesis at 27 weeks of gestation revealed a karyotype of 46, XX (10/10 colonies) in cultured amniocytes, and interphase FISH analysis on uncultured amniocytes revealed 20% (20/100 cells) mosaicism for tetrasomy 9p. The parental karyotypes and prenatal ultrasound were normal. At 39 weeks of gestation, a phenotypically normal 3388-g female baby was delivered. The karyotypes of cord blood, umbilical cord and placenta were 47,XX,+idic (9) (q12)[19]/46,XX [21] or 47,XX,+idic (9) (pter→q12:q12→pter)[19]/46,XX [21], 47,XX,+idic (9) (q12)[1]/46,XX [39] and 47,XX,+idic (9) (q12)[4]/46,XX [36], respectively. When follow-up at age two months, the neonate was phenotypically normal, the peripheral blood had a karyotype of 47,XX,+idic (9) (q12)[18]/46,XX [22], and interphase FISH analysis on 100 buccal mucosal cells revealed 1% (1/100 cells) mosaicism for tetrasomy 9p. When follow-up at age seven months, the neonate was phenotypically normal, and the peripheral blood had a karyotype of 47,XX,+idic(9)(q12)[14]/46,XX[26]. CONCLUSION: Mosaic tetrasomy 9p at amniocentesis can be a transient and benign condition, and can be associated with a favorable fetal outcome and perinatal progressive decrease of the aneuploid cell line and cytogenetic discrepancy in various tissue.

Case Report: Prenatal diagnosis of fetal tetrasomy 9p initially identified by non-invasive prenatal testing.

Tetrasomy 9p is a rare syndrome characterized by fetal growth restriction, Dandy-Walker malformation, cardiac anomalies, and facial abnormalities and is discovered by ultrasound during the prenatal examination. Herein, we report a fetus of tetrasomy 9p without obvious phenotypic manifestations during the first trimester that was identified by non-invasive prenatal testing (NIPT). NIPT revealed that the gain of 9p24.3-9p11 that was approximately 46.36 Mb in size. Karyotyping of amniocytes indicated an additional marker in all metaphase. Chromosome microarray and fluorescence in situ hybridization on uncultured amniocytes revealed tetrasomic of 9p24.3q13, and that the supernumerary chromosome is a dicentric isochromosome consisted of two copies of the 9p arm. Taken together, it was indicated that the fetal karyotype was 47,XY,+idic (9) (q13), and that multiple techniques are crucial to the prenatal diagnosis.

Clinical, Cognitive and Neurodevelopmental Profile in Tetrasomies and Pentasomies: A Systematic Review.

Background: Sex chromosome aneuploidies (SCAs) are a group of disorders characterised by an abnormal number of sex chromosomes. Collective prevalence rate of SCAs is estimated to be around 1 in 400-500 live births; sex chromosome trisomies (e.g., XXX, XXY, XYY) are most frequent, while tetra- and pentasomies (e.g., XXXX, XXXXX, XXXY, XXXXY) are rarer, and the most common is 48, XXYY syndrome. The presence of additional X and/or Y chromosomes is believed to cause neurodevelopmental differences, with increased risk for developmental delays, language-based learning disabilities, cognitive impairments, executive dysfunction, and behavioural and psychological disorders. Aim of the Study: Our review has the purpose of analysing the neurocognitive, linguistical and behavioural profile of patients affected by sex chromosomes supernumerary aneuploidies (tetrasomy and pentasomy) to better understand the specific areas of weakness, in order to provide specific rehabilitation therapy. Methods: The literature search was performed by two authors independently. We used MEDLINE, PubMed, and PsycINFO search engines to identify sources of interest, without year or language restrictions. At the end of an accurate selection, 16 articles fulfilled the inclusion and exclusion criteria. Results and Conclusions: International literature has described single aspects of the neuropsychological profile of 48, XXYY and 49, XXXXY patients. In 48, XXYY patients, various degrees of psychosocial/executive functioning issues have been reported and there is an increased frequency of behavioural problems in childhood. Developmental delay and behavioural problems are the most common presenting problems, even if anxiety, depression and oppositional defiant disorder are also reported. They also show generalized difficulties with socialization and communication. Cognitive abilities are lower in measures of verbal IQ than in measures of performance IQ. Visuospatial skills are a relative strength compared to verbal skills. In patients with 49, XXXXY, both intellectual and adaptive functioning skills fall into the disability range, with better non-verbal cognitive performance. Speech and language testing reveals more deficits in expressive language than receptive language and comprehension. Anxiety, thought problems, internalizing and externalizing problems, and deficits in social cognition and communication are reported. Behavioural symptoms lessen from school age to adolescence, with the exception of thought problems and anxiety. Individuals affected by sex chromosome aneuploidies show testosterone deficiency, microorchidism, lack of pubertal progression and infertility. Hormone replacement therapy (HRT) is usually recommended for these patients: different studies have found that testosterone-based HRT benefit a wide range of areas initiated in these disorders, affecting not only neuromotor, cognitive and behavioural profile but also structural anomalies of the brain (i.e., increase of volume of grey temporal lobe matter). In conclusion, further studies are needed to better understand the neuropsychological profile with a complete evaluation, including neurocognitive and psychosocial aspects and to establish the real impact of HRT on improving the cognitive and behavioural profile of these patients.

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.

De Novo Mosaic 6p23-p25.3 Tetrasomy Caused by a Small Supernumerary Marker Chromosome Presenting Trisomy Distal 6p Phenotype: A Case Report and Literature Review.

Small supernumerary marker chromosomes (sSMCs) derived from the chromosome 6 short arm are rare and their clinical significance remains unknown. No case with sSMC(6) without centromeric DNA has been reported. Partial trisomy and tetrasomy of distal 6p is a rare but clinically distinct syndrome. We report on a de novo mosaic sSMC causing partial tetrasomy for 6p23-p25.3 in a male infant with symptoms of being small for gestational age, microcephaly, facial dysmorphism, congenital eye defects, and multi-system malformation. Conventional cytogenetic analysis revealed a karyotype of 47,XY,+mar [25]/46,XY [22]. Array comparative genomic hybridization (aCGH) revealed mosaic tetrasomy of distal 6p. This is the first case of mosaic tetrasomy 6p23-p25.3 caused by an inverted duplicated neocentric sSMC with characteristic features of trisomy distal 6p. Comparison of phenotypes in cases with trisomy and tetrasomy of 6p23-p25.3 could facilitate a genotype-phenotype correlation and identification of candidate genes contributing to their presentation. The presentation of anterior segment dysgenesis and anomaly of the renal system suggest triplosensitivity of the FOXC1 gene. In patients with microcephaly growth retardation, and malformation of the cardiac and renal systems, presentation of anterior segment dysgenesis might be indicative of chromosome 6p duplication, and aCGH evaluation should be performed for associated syndromic disease.

Minimally invasive endoscopic fenestration of a spinal arachnoid cyst in a child with tetrasomy 18p: illustrative case.

BACKGROUND: Spinal arachnoid cysts (SAC) are rare, especially in children. Patients can be asymptomatic or present symptoms of spinal cord compression. In this latter case, surgery is indicated to relieve the compression. Different surgical techniques have been described to treat these cysts, endoscopic or endoscopy-assisted fenestration being the least invasive. Tetrasomy 18p describes the condition in which two copies of the short arms of chromosome 18 are present. It is an extremely rare pathology with a variable phenotype, including 100% of cases cognitive impairment and developmental delay. Different central nervous system (CNS) abnormalities have been found in these patients. OBSERVATIONS: The authors describe the case of a 3-year-old boy with a tetrasomy 18p and a wide spinal arachnoid cyst that received an endoscope-assisted treatment with a significantly improved motor outcome. LESSONS: Tetrasomy 18p is an extremely rare pathology and different CNS abnormalities have been described in association with, but to date spinal arachnoid cyst has never been reported. These children typically show global hypotonia and cognitive impairment. The authors recommend a thorough neurological assessment with cranio-spinal magnetic resonance imaging to rule out any possible malformation that could be improved by surgery.

Prenatal genetic diagnosis of tetrasomy 18p from maternal trisomy 18p: a case report.

BACKGROUND: Tetrasomy 18p syndrome is a rare chromosomal disorder that is caused by the presence of isochromosome 18p. Most tetrasomy 18p cases are de novo cases and maternal origin of trisomy 18p is a rare condition. At present, only four cases of maternal origin have been reported in worldwide.This is the fifth case of tetrasomy 18p originating from maternal trisomy 18p. The mother of the fetus studied had no apparent disease phenotype. CASE PRESENTATION: The current case report is to describe a fetus with confirmed 18p tetrasomy as detected by karyotyping and Single Nucleotide Polymorphism array (SNP array) analysis. However, the fetus showed normal phenotypic features that were observed using ultrasound scans. The mother and maternal grandfather were phenotypically normal and healthy; however, they were diagnosed with trisomy 18p, which was confirmed by conventional karyotyping and SNP array. CONCLUSIONS: We report a case of 18p tetrasomy in a fetus whose mother and grandfather had 18p trisomy. The mother and grandfather were phenotypically normal. Our case report findings provide an important reference for the genetic counseling of trisomy 18p in the future.

A very rare case of a newborn with tetrasomy 9p and literature review.

BACKGROUND: Tetrasomy 9p is a rare genetic condition which usually results from a supernumerary isochromosome derived from the short arm of chromosome 9. Phenotypic findings include multiple congenital anomalies, facial dysmorphism, growth and developmental delays, and also vary according to the presence and degree of mosaicism. CASE: We report on a newborn with tetrasomy 9p who deceased in the newborn period. She had facial features including low-set and anteverted ears, hypertelorism, prominent nasal bridge, and microretrognathia. Bilateral ventriculomegaly, vermian hypoplasia and corpus callosum agenesis were detected on magnetic resonance imaging and double outlet right ventricle (tetralogy of Fallot type), secundum atrial septal defect, and persistent left superior vena cava were displayed by echocardiography. Microarray analysis revealed 38,584 kb tetrasomic region at 9p24.3p13.1. We also present a review of the literature suggesting that there is a recognizable phenotype for this condition and an assessment of cardiac manifestations based on the size and the localization of the breakpoints. CONCLUSIONS: We conclude that cardiac manifestations do not differ according to the localization of the breakpoint. Persistent left superior vena cava seems to be consistent with breakpoints distal to q12, but the present case is different from them by breakpoint p13.1.

Cognitive, Behavioral, and Sensory Profile of Pallister-Killian Syndrome: A Prospective Study of 22 Individuals.

BACKGROUND: Developmental delay and intellectual disability are two pivotal elements of the phenotype of Pallister-Killian Syndrome (PKS). Our study aims to define the cognitive, adaptive, behavioral, and sensory profile of these patients and to evaluate possible correlations between the different aspects investigated and with the main clinical and demographic variables. METHODS: Individuals of any age with genetically confirmed PKS were recruited. Those ≤ 42 months were administered the Bayley Scales of Infant and Toddler Development Third Edition (Bayley-III), and those > 42 months the Vineland Adaptive Behavior Scales-Second Edition (Vineland-II). Stereotyped behaviors (Stereotypy Severity Scale, SSS) and aggressive behaviors (Behavior Problems Inventory-Short Version, BPIs) were assessed in all subjects > 1 year; sensory profile (Child Sensory Profile 2, C-SP2) in all aged 2-18 years. RESULTS: Twenty-two subjects were enrolled (11 F/11 M; age 9 months to 28 years). All subjects ≤ 42 months had psychomotor developmental delay. Of the subjects > 42 months, 15 had low IQ deviation, and 1 in the normal range. Stereotypies were frequent (median SSS-total score 25/68). Lower Vineland-II values corresponded to greater intensity and frequency of stereotypies (p = 0.004 and p = 0.003), and self-injurious behaviors (p = 0.002 and p = 0.002). Patients with severe low vision had greater interference of stereotypies (p = 0.027), and frequency and severity of aggressive behaviors (p = 0.026; p = 0.032). The C-SP2, while not homogeneous across subjects, showed prevalence of low registration and sensory seeking profiles and hypersensitivity to tactile and auditory stimuli. Lower Vineland-II scores correlated with higher Registration scores (p = 0.041), while stereotypies were more frequent and severe in case of high auditory sensitivity (p = 0.019; p = 0.007). Finally, greater sleep impairment correlated with stereotypies and self-injurious behaviors, and lower Vineland-II scores. CONCLUSIONS: The present study provides a further step in the investigation of the etiopathogenesis of the syndrome. Furthermore, these aspects could guide rehabilitation therapy through the identification of targeted protocols.

Prenatal diagnosis of a case with tetrasomy 9p confirmed by cytogenetics, FISH, microarray analysis and review.

OBJECTIVE: Tetrasomy 9p is a rare fetal condition. Cases are usually mosaic. Here, we present a non-mosaic tetrasomy 9p case with cytogenetic analysis, fluorescence in situ hybridization, microarray data, ultrasound findings, and phenotypic presentation. CASE REPORT: A pregnancy was referred to cytogenetic analysis because of increased nuchal translucency in prenatal ultrasound at 13 weeks of gestation. Prenatal laboratory analysis revealed an extra marker chromosome with a non-mosaic pattern. Ultrasonographic findings were unilateral cleft lip and palate, micrognathia, and atrioventricular septal defect at the 17th week; additionally, ventriculomegaly, left axis deviation of the fetal heart, and a single umbilical artery were determined at the 23rd week. CONCLUSION: Phenotypic severity in non-mosaic tetrasomy 9p widely differs depending on the chromosomal content. We recommend performing appropriate genetic tests in those pregnancies with the suspicion of tetrasomy 9p, evaluating the mosaic state, and following those cases with detailed ultrasonographic examinations.

Partial tetrasomy 18 mosaicism: Pre and postnatal diagnosis of a unique pattern.

OBJECTIVE: To present prenatal diagnosis and cytogenetic characterization of a unique pattern of partial tetrasomy 18 mosaicism. CASE REPORT: A 34-year-old woman underwent amniocentesis at 25 weeks of gestation due to anomalies detected in obstetric ultrasound. It revealed a de novo supernumerary partial isochromosome 18 in 11 of 37 metaphases of cultured amniocytes. The karyotype was 47,XX,+idic(18) (q12.3)[11]/46,XX[26]. Elective cesarean section was performed at 33 weeks of gestational age due to anhydramnios. A female symmetric small for gestational age baby with dysmorphic features and an Apgar score of 9/10/10 was born. She had a good clinical outcome during hospitalization. Postnatal peripheral blood karyotype was normal. Interphase fluorescence in situ hybridization in a sample of the oral mucosa confirmed the prenatal diagnosis. At three months of corrected age she had a normal psychomotor development. CONCLUSION: To the best of our knowledge, this is the first reported case of mosaic partial tetrasomy 18 including segments of the long arm. This newborn's relatively mild phenotype highlights the challenges of prenatal genetic counselling in mosaic cases with fetal anomalies.

A novel coexistence of tetrasomy 8 and FLT3-ITD along with variant 3 way translocation t(4;17;15) in acute promyelocytic leukemia: Case study and literature review.

Here, we report a case of Acute promyelocytic leukemia (APL) with three way complex translocation involving chromosomes 4, 15, and 17. Although chromosome 4 is most commonly associated chromosome in three way translocation, present case is the first report with four novel co-existent findings of new break point region on chromosome 4, new cyclic mechanism with simultaneous breaks, presence of a co-existent tetrasomy 8 and FLT3 ITD positivity.; Comprehensive assessment highlight the utility of combining morphology, immunophenotyping, karyotyping, fluorescence in situ hybridization, and molecular studies for better characterization, optimal management of APL with a better understanding of the pathogenic mechanism and prognosis of the disease.

The first post-natal clinical description of true mosaic complete tetrasomy 21: A case report.

Tetrasomy 21 is a rare occurrence. Only 14 cases have been reported in the literature, 8 of which are partial tetrasomy cases and 6 which are complete tetrasomy cases. Of the incidences, no proband with true complete tetrasomy 21 has survived the neonatal period. We report complete mosaic tetrasomy 21 in a female infant with the typical Down syndrome phenotype, including Hirschsprung's disease and atrioventricular (AV) canal defect. This is in contrast to cases of partial tetrasomy 21, which often have an atypical trisomy 21 presentation and multiple nonspecific traits, including short stature, microcephaly, and developmental delays. This case demonstrates the difference in clinical presentation between the partial and complete subtype of tetrasomy 21 and provides the first postnatal clinical picture of an infant with true mosaic complete tetrasomy 21.