How does terminal 21q22 deletion really manifest? Delineation based on prenatal diagnosis and literature review.

OBJECTIVE: Most genetic disorders, especially rare and manifested with an unspecific constellation of developmental anomalies, are challenging to diagnose before birth. The paper aims to present a rare case of terminal 21q22 deletion to extend the knowledge on this rare genetic disease, mostly to facilitate prenatal guidance by pointing the diagnostic features. CASE REPORT: The fetus was diagnosed prenatally, at 21 weeks of gestation, due to ultrasound markers detected in a routine ultrasound scan. Post-mortem dysmorphological assessment has verified the diagnosis. To the best of our knowledge, this is the second report of prenatal presentation of partial monosomy 21q. CONCLUSION: By giving the detailed phenotype description and presenting a comprehensive literature review on the subject, we delineate its phenotype, which was different from what has been shown in the literature. Specifically, the clinical presentation of aberration within regions 2 and 3 (referring to the term proposed by Lyle et al., in 2009) of 21q22 bands is not characterised by multiple or severe malformations, which matters for prenatal counselling and diagnostics.

Partial trisomy 16q and partial monosomy 7p of a fetus derivated from paternal balanced translocation: A case report.

INTRODUCTION: Subchromosomal deletions and duplications could currently be detected by noninvasive preliminary screening (NIPS). However, NIPS is a screening test that requires further diagnosis. Here we report a fetus with an autosomal abnormality revealed by NIPS and conventional karyotype combined with copy number variations sequencing (CNV-seq) confirmed the fetus with an unbalanced translocation. PATIENT CONCERN: This was the fourth pregnancy of a 30-year-old woman who underwent 2 spontaneous abortions and gave birth to a child with a normal phenotype. The woman and her husband were healthy and nonconsanguineous. NIPS indicated a repeat of about 19-Mb fragment at the region of 16q22.1-q22.4 at 17-week gestation. DIAGNOSES: The combination of traditional karyotype and CNV-seq could better locate the abnormal chromosomal region and further identify the source of fetal chromosomal abnormalities. Simultaneously, we evaluated the fetal morphology by ultrasound examination. The karyotype of the fetus was 46,XX,der(7)t(7;16)(p22;q23) and CNV-seq results showed an approximately 20.96-Mb duplication in 16q22.1-q24.3 (69200001-90160000) and an approximately 3.86-Mb deletion in 7p22.3-p22.2 (40001-3900000). Prenatal ultrasound revealed the fetal micrognathia. The paternal karyotype was 46,XY, t (7;16) (p22;q23), while the maternal was normal. The fetus inherited an abnormal chromosome 7 from its father. INTERVENTIONS: No treatment for the fetus. OUTCOMES: Pregnancy was terminated. CONCLUSIONS: To our knowledge, the occurrence of de novo partial trisomy 16q (16q22.1-qter) and partial monosomy 7p (7p22.2-pter) has not previously been reported up to now. Here, we present the perinatal findings of such a case and a review of the literatures. CNV-seq combined with karyotype is a useful tool for chromosomal abnormalities indicated by NIPS.

Fluorescence in situ hybridization detection of chromosome 22 monosomy in pleural effusion cytology for the diagnosis of mesothelioma.

BACKGROUND: Malignant pleural mesothelioma (MPM) is characterized by mutations in several genes, including cyclin-dependent kinase-inhibitor 2A/p16 in the 9p21 locus, BRCA1-associated protein 1 (BAP1), and neurofibromatosis type 2 (NF2) in the 22q12 locus. Recent studies indicate that fluorescence in situ hybridization (FISH) detects hemizygous loss of NF2 in tissue specimens of MPM. The authors investigated whether NF2 FISH, either alone or in combination with other diagnostic assays (9p21 FISH, methylthioadenosine phosphorylase [MTAP] immunohistochemistry [IHC], and BAP1 IHC), effectively distinguishes MPM cells from reactive mesothelial cells (RMCs) in cell blocks prepared from pleural effusions. METHODS: FISH assays were used to examine the deletion status of NF2 and 9p21, and IHC was used to determine the expression of MTAP and BAP1 in cell blocks from 54 cases with MPM and 18 cases with RMCs. RESULTS: Hemizygous NF2 loss (chromosome 22 monosomy or hemizygous deletion) showed 51.9% sensitivity (48.1% for chromosome 22 monosomy and 3.7% for hemizygous deletion) and 100% specificity in differentiating MPM cells from RMCs. Combinations of NF2 FISH, 9p21 FISH, and BAP1 IHC assays yielded greater sensitivity (98.1%) than any assay alone (9p21 FISH, 61.1%; MTAP IHC, 52.8%; or BAP1 IHC, 60.4%). The level of hemizygous NF2 loss in cell blocks positively correlated with that in corresponding tissues. Furthermore, to overcome cytologic specimen-specific challenges, FISH combined with cytokeratin AE1/AE3 immunofluorescence was necessary in 25.9% of MPM cases for FISH assessment of predominantly scattered MPM cells. CONCLUSIONS: NF2 FISH alone or in combination with other diagnostic assays effectively differentiates MPM cells from RMCs in cell blocks prepared from pleural effusions.

Monosomal karyotype and chromosome 17p loss or TP53 mutations in decitabine-treated patients with acute myeloid leukemia.

TP53 aberrations reportedly predict favorable responses to decitabine (DAC) in acute myeloid leukemia (AML). We evaluated clinical features and outcomes associated with chromosome 17p loss or TP53 gene mutations in older, unfit DAC-treated AML patients in a phase II trial. Of 178 patients, 25 had loss of 17p in metaphase cytogenetics; 24 of these had a complex (CK+) and 21 a monosomal karyotype (MK+). In analyses in all patients and restricted to CK+ and MK+ patients, 17p loss tended to associate with higher rates of complete remission (CR), partial remission (PR), or antileukemic effect (ALE). Despite favorable response rates, there was no significant OS difference between patients with or without loss of 17p in the entire cohort or in the CK+ and MK+ cohort. TP53 mutations were identified in eight of 45 patients with material available. Five of the eight TP53-mutated patients had 17p loss. TP53-mutated patients had similar rates of CR/PR/ALE but shorter OS than those with TP53 wild type (P = 0.036). Moreover, patients with a subclone based on mutation data had shorter OS than those without (P = 0.05); only one patient with TP53-mutated AML had a subclone. In conclusion, 17p loss conferred a favorable impact on response rates, even among CK+ and MK+ patients that however could not be maintained. The effect of TP53 mutations appeared to be different; however, patient numbers were low. Future research needs to further dissect the impact of the various TP53 aberrations in HMA-based combination therapies. The limited duration of favorable responses to HMA treatment in adverse-risk genetics AML should prompt physicians to advance allografting for eligible patients in a timely fashion.

Prenatal diagnosis and molecular cytogenetic characterization of a de novo interchromosomal insertion of ins(1;8)(p22.1;q22q23).

OBJECTIVE: We present prenatal diagnosis and molecular cytogenetic characterization of a de novo interchromosomal insertion of ins(1; 8)(p22.1; q22q23) at amniocentesis. CASE REPORT: A 34-year-old woman underwent amniocentesis at 18 weeks of gestation because of advanced maternal age. Conventional cytogenetic analysis revealed a chromosome 1p22.1 interstitial duplication and a chromosome 8q22-q23 interstitial deletion. The parental karyotypes were normal. Array comparative genomic hybridization (aCGH) analysis using the DNA extracted from cultured amniocytes revealed no genomic imbalance. Metaphase fluorescence in situ hybridization (FISH) analysis on cultured amniocytes showed an interchromosomal insertion of ins(1; 8)(p22.1; q22q23) or ins(1; 8) (1pter→1p22.1::8q23→8q22::1p22.1→1qter; 8pter→8q22::8q23→8qter). The long arm of chromosome 8 between bands 8q22 and 8q23 had been directly inserted into the short arm of chromosome 1 at band 1p22.1. The karyotype was 46,XY,ins(1; 8)(p22.1; q22q23) or 46,XY,ins(1; 8)(1pter→1p22.1::8q23→8q22::1p22.1→1qter; 8pter→8q22::8q23→8qter). After genetic counseling, the parents decided to continue the pregnancy. A phenotypically normal male baby was delivered at term. CONCLUSION: FISH and aCGH are useful for genetic counseling and molecular cytogenetic characterization of a de novo interchromosomal insertion detected by amniocentesis.

Prenatal diagnosis of concomitant distal 5q duplication and terminal 10q deletion in a fetus with intrauterine growth restriction, congenital diaphragmatic hernia and congenital heart defects.

OBJECTIVE: We present prenatal diagnosis of concomitant distal 5q duplication and terminal 10q deletion in a fetus with intrauterine growth restriction (IUGR), congenital diaphragmatic hernia (CDH) and congenital heart defects (CHD). CASE REPORT: A 34-year-old, gravida 4, para 2, woman was referred for amniocentesis at 21 weeks of gestation because of advanced maternal age and IUGR. There was no congenital malformation in the family. Amniocentesis revealed a derivative chromosome 10 with an additional maternal on the terminal region of 10q. Array comparative genomic hybridization (aCGH) analysis on the DNA extracted from the cultured amniocytes revealed a result of arr 5q31.3q35.5 (142, 548, 354-180,696,806) × 3.0, arr 10q26.3 (132, 932, 808-135,434,178) × 1.0 [GRCh37 (hg19)] with a 2.50-Mb deletion of 10q26.3 encompassing 19 [Online Mendelian Inheritance in Man (OMIM)] genes and a 38.15-Mb duplication of 5q31.3-q35.5 encompassing 195 OMIM genes including four CDH candidate genes of NDST1, ADAM19, NSD1 and MAML1. The mother was found to have a karyotype of 46,XX,t(5; 10) (q31.3; q26.3). Therefore, the fetal karyotype was 46,XX,der(10)t(5; 10)(q31.3; q26.3)mat. Prenatal ultrasound showed IUGR, right CDH, transposition of great artery, double outlet of right ventricle and right atrial isomerism. The pregnancy was terminated, and a malformed fetus was delivered with facial dysmorphism. CONCLUSION: Fetuses with concomitant distal 5q duplication and terminal 10q deletion may present IUGR, CDH and CHD on prenatal ultrasound.

Prenatal diagnosis of partial monosomy 21q (21q22.1→qter) associated with intrauterine growth restriction and corpus callosum dysgenesis.

OBJECTIVE: A prenatal diagnosis of partial monosomy 21q(21q22.1→ qter) in fetus with intrauterine growth restriction and corpus callosum dysgenesis but escaped from the detection by cell free DNA testing was reported. CASE REPORT: A 31-year-old, primigravida women, presented with intrauterine growth restriction and corpus callosum dysgenesis at 23 weeks of gestational age by anatomic ultrasound screening. The interphase fluorescence in situ hybridization (FISH) analysis on amniocytes revealed monosomy 21, while the cytogenetic analysis and array comparative genomic hybridization (CGH) with CytoScan gene chip ascertained a 12.35 Mb deletion at 21q22.1q22.3. CONCLUSION: Although noninvasive prenatal testing is used extensively and can be applied to certain microdeletion diseases, the application for uncommon deletion disorders such as the present case remains limited. Prenatal examination with detailed ultra-sonography combined with different modalities of invasive prenatal testing can provide a more comprehensive information.

ATR-16 syndrome: mechanisms linking monosomy to phenotype.

BACKGROUND: Deletions removing 100s-1000s kb of DNA, and variable numbers of poorly characterised genes, are often found in patients with a wide range of developmental abnormalities. In such cases, understanding the contribution of the deletion to an individual's clinical phenotype is challenging. METHODS: Here, as an example of this common phenomenon, we analysed 41 patients with simple deletions of ~177 to ~2000 kb affecting one allele of the well-characterised, gene dense, distal region of chromosome 16 (16p13.3), referred to as ATR-16 syndrome. We characterised deletion extents and screened for genetic background effects, telomere position effect and compensatory upregulation of hemizygous genes. RESULTS: We find the risk of developmental and neurological abnormalities arises from much smaller distal chromosome 16 deletions (~400 kb) than previously reported. Beyond this, the severity of ATR-16 syndrome increases with deletion size, but there is no evidence that critical regions determine the developmental abnormalities associated with this disorder. Surprisingly, we find no evidence of telomere position effect or compensatory upregulation of hemizygous genes; however, genetic background effects substantially modify phenotypic abnormalities. CONCLUSIONS: Using ATR-16 as a general model of disorders caused by CNVs, we show the degree to which individuals with contiguous gene syndromes are affected is not simply related to the number of genes deleted but depends on their genetic background. We also show there is no critical region defining the degree of phenotypic abnormalities in ATR-16 syndrome and this has important implications for genetic counselling.

A rapid and reliable chromosome analysis method for products of conception using interphase nuclei.

BACKGROUND: Karyotype determination has a central role in the genetic workup of pregnancy loss, as aneuploidy (trisomy and monosomy) and polyploidy (triploidy and tetraploidy) are the cause in at least 50% of first trimester, 25% of second trimester, and 11% of third trimester miscarriages. There are several limitations with the current approaches of obtaining a karyotype using traditional cytogenetics, fluorescence in situ hybridization with a limited number of probes, and chromosomal microarray. These include culture failure, incomplete results, lower sensitivity, and longer reporting time. METHODS: To overcome current limitations, a novel molecular assay is developed with a Standard Resolution Interphase Chromosome Profiling probe set which is a variation of the recently developed High Resolution probe set. It generates a molecular karyotype that can detect all major changes commonly associated with pregnancy loss. Initial familiarization of signal patterns from the probe set was used, followed by validation of the method using 83 samples from miscarriages in a blind study from three different laboratories. Finally, the clinical utility of the method was tested on 291 clinical samples in two commercial reference laboratory settings on two different continents. RESULTS: The new molecular approach not only identified all the chromosome changes observed by current methods, but also significantly improved abnormality detection by characterizing derivative chromosomes and finding subtle subtelomeric rearrangements, balanced and unbalanced. All Robertsonian translocations were also detected. The abnormality rate was 54% on clinical samples from commercial laboratory 1 and 63% from laboratory 2. CONCLUSION: The attributes of this method make it an ideal choice for the genetic workup of miscarriages, namely (1) near 100% successful results, (2) greater sensitivity than conventional chromosome analysis or FISH panels, (3) rapid reporting time, and (4) favorable comparisons with chromosomal microarray.

Prenatal diagnosis of an 8q22.2-q23.3 deletion associated with bilateral cleft lip and palate and intrauterine growth restriction on fetal ultrasound.

OBJECTIVE: We present prenatal diagnosis of an interstitial 8q22.2-q23.3 deletion associated with bilateral cleft lip and palate and intrauterine growth restriction (IUGR) on fetal ultrasound. CASE REPORT: A 29-year-old, primigravid woman underwent elective amniocentesis at 17 weeks of gestation because of anxiety. Amniocentesis revealed a karyotype of 46, XX. However, level II ultrasound at 21 weeks of gestation revealed a fetus with IUGR and bilateral cleft lip and palate. Repeat amniocentesis was performed at 21 weeks of gestation, and array comparative genomic hybridization using uncultured amniocytes revealed a 13.5-Mb interstitial deletion of 8q22.2-q23.3 encompassing 37 Online Mendelian Inheritance of in Man (OMIM) genes including SPAG1, GRHL2, NCALD, RRM2B and ZFPM2. Polymorphic DNA marker analysis determined a paternal origin of the deletion. The pregnancy was subsequently terminated, and a malformed fetus was delivered with a depressed nose and bilateral cleft lip and palate. CONCLUSION: Prenatal diagnosis of facial cleft with IUGR should raise a suspicion of subtle chromosome deletions.

Miocardiopatía no compactada asociada a síndrome 1P36 / Non-compaction cardiomyopathy associated to 1P36 syndrome

La miocardiopatía no compa da (MNC) es una enf medad congénita caracterizada por la ausencia de compaqctación del miocardio ventricular. Tiene una gran variabilidad genética, clinica, evolutiva y pronóstica. Presentamos a una recién nacida pretérmino (34 semanas) con restrición del crecimiento intrauterino, fenotipo peculiar, hipotonia generalizada y distrés respiratono. La ecocardiografía objetiva ausencia de compactación del ventrículo izquierdo y disfunción sistólica leve, que se trata con captopril y ácido acetilsalicílico. Desarrolla crisis convulsivas parciales resistentes al tratamiento y se evidencia ausencia de respuesta en potenciales auditivo-visuales del tronco del encéfalo. El cariotipo convencional es normal pero el estudio de microarrays revela deleción 1p36.33-p36.23. El estudio carddiológico y genético de los progenitores es normal. El conocimiento de esta cardiopatía permite un diagnóstico precoz. Debe realizarse despistaje a familiares de primer grado. Dada la frecuente asociación entre MNC y síndrome 1p36 recomendamos incluir estudio genético mediante microarrays en pacientes con sospecha de asociación sindrómica y normalidad en el cariotipo convencional, como en el caso que presentamos (AU)

The non-compaction cardiomypathy (MNC) is a congenital disorder characterized by the absence of the compaction ventricular myocardium. It presents a high variability, genetic, clinical, evolutionary and prognostic. We report a preterm newborn (34 weeks) with intrauterine growth restriction particular phenotype, generalized hypotonia and respiratory distress. Echocardiography objective absence of compaction left ventricular myocardium and mild sistolic dysfunction, treated with captopril and acetylsalicylic acid. Develops resistant treatment partial seizurcs and lack response evident in visual-auditory evoked potentials brainstem. The conventional kariotype is normal but the microarray study revealed 1p.36-p36.23 deletion. Cardiological and genetic study of the parents are normal. Thebest knowledge of the MNC allows earlier diagnosis. Have to perform screening for first-degree relatives. Given the frequent association between MNC and lp36 syndrome, we recommend using microarray genetic study in patients with suspected syndromic association and normality in the conventional as in the case presented (AU)

Comprehensive chromosome screening and gene expression analysis from the same biopsy in human preimplantation embryos.

STUDY QUESTION: Can simultaneous comprehensive chromosome screening (CCS) and gene expression analysis be performed on the same biopsy of preimplantation human embryos? SUMMARY ANSWER: For the first time, CCS and reliable gene expression analysis have been performed on the same human preimplantation embryo biopsy. WHAT IS KNOWN ALREADY: A single trophectoderm (TE) biopsy is routinely used for many IVF programs offering CCS for selection of only chromosomally normal embryos for transfer. Although the gene expression profiling of human preimplantation embryos has been described, to date no protocol allows for simultaneous CCS and gene expression profiling from a single TE biopsy. STUDY DESIGN, SIZE AND DURATION: This is a proof of concept and validation study structured in two phases. In Phase 1, cell lines were subjected to a novel protocol for combined CCS and gene expression analysis so as to validate the accuracy and reliability of the proposed protocol. In Phase 2, 20 donated human blastocysts were biopsied and processed with the proposed protocol in order to obtain an accurate CCS result and characterize their gene expression profiles using the same starting material. PARTICIPANTS/MATERIALS, SETTING AND METHOD: A novel protocol coupling quantitative real-time PCR-based CCS and gene expression analysis using RT-PCR was designed for this study. Phase 1: six-cell aliquots of well-characterized fibroblast cell lines (GM00323, 46,XY and GM04435, 48,XY,+16,+21) were subjected to the proposed protocol. CCS results were compared with the known karyotypes for consistency, and gene expression levels were compared with levels of purified RNA from same cell lines for validation of reliable gene expression profiling. Phase 2: four biopsies were performed on 20 frozen human blastocysts previously diagnosed as trisomy 21 (10 embryos) and monosomy 21 (10 embryos) by CCS. All samples were processed with the proposed protocol and re-evaluated for concordance with the original CCS result. Their gene expression profiles were characterized and differential gene expression among embryos and early embryonic cell lineages was also evaluated. MAIN RESULTS AND THE ROLE OF CHANCE: CCS results from cell lines showed 100% consistency with their known karyotypes. ΔΔCt values of differential gene expression of four selected target genes from the cell lines GM4435 and GM0323 were comparable between six-cell aliquots and purified RNA (Collagen type I alpha-1 (COL1A1), P = 0.54; Fibroblast growth factor-5 (FGF5), P = 0.11; Laminin subunit beta-1 (LAMB1), P = 1.00 and Atlastin-1 (ATL1), P = 0.23). With respect to human blastocysts, 92% consistency was reported after comparing embryonic CCS results with previous diagnosis. A total of 30 genes from a human stem cell pluripotency panel were selected to evaluate gene expression in human embryos. Correlation coefficients of expression profiles from biopsies of the same embryo (r = 0.96 ± 0.03 (standard deviation), n = 45) were significantly higher than when biopsies from unrelated embryos were evaluated (r = 0.93 ± 0.03, n = 945) (P < 0.0001). Growth differentiation factor 3 (GDF3) was found to be significantly up-regulated in the inner cell mass (ICM), whereas Caudal type homebox protein-2 (CDX2), Laminin subunit alpha-1 (LAMA1) and DNA methyltransferase 3-beta (DNMT3B) showed down-regulation in ICM compared with TE. Trisomy 21 embryos showed significant up-regulation of markers of cell differentiation (Cadherin-5 (CDH5) and Laminin subunit gamma-1 (LAMC1)), whereas monosomy 21 blastocysts showed higher expression of genes reported to be expressed in undifferentiated cells (Gamma-Aminobutyric Acid Type-A Receptor Beta3 Subunit (GABRB3) and GDF3). LARGE SCALE DATA: N/A. LIMITATIONS, REASONS FOR CAUTION: Gene expression profiles of chromosomally normal embryos were not assessed due to restrictive access to euploid embryos for research. Nonetheless, the profile of blastocysts with single aneuploidies was characterized and compared. Only 30 target genes were analyzed for gene expression in this study. Increasing the number of target genes will provide a more comprehensive transcriptomic signature and reveal potential pathways paramount for embryonic competence and correct development. WIDER IMPLICATIONS OF THE FINDINGS: This is the first time that CCS and gene expression analysis have been performed on the same human preimplantation embryo biopsy. Further optimization of this protocol with other CCS platforms and inclusion of more target genes will provide innumerable research and clinical applications, such as discovery of biomarkers for embryonic reproductive potential and characterization of the transcriptomic signatures of embryos, potentially allowing for further embryo selection prior to embryo transfer and therefore improving outcomes. STUDY FUNDING AND COMPETING INTERESTS: This study was funded by the Foundation for Embryonic Competence, Basking Ridge, NJ, USA. No conflicts of interests declared.

A Clone with 5, 17 and 18 Monosomies as Stemline in a Patient with De novo Acute Myeloid Leukemia.

In brief, we present a case of acute myeloid leukemia (AML) with 5, 17 and 18 monosomies as stemline clonal abnormality in his cytogenetic analysis. To the best of our knowledge, this is the first report of such a chromosomal abnormality as a clonal aberration in AML with M0 French-American-British (FAB) type. It seems that this monosomal karyotype imposed adverse prognosis on this patient and could be related to the rapid and malignant course of the disease as seen.

Follow-up of multiple aneuploidies and single monosomies detected by noninvasive prenatal testing: implications for management and counseling.

OBJECTIVES: To determine the underlying biological basis for noninvasive prenatal testing (NIPT) results of multiple aneuploidies or autosomal monosomies. METHODS: Retrospective analysis of 113,415 tests to determine the study cohort, consisting of 138 (0.12%) cases reported as a single autosomal monosomy (n = 65), single trisomy with a sex chromosome aneuploidy (n = 36), or with multiple aneuploidies (n = 37). Clinical outcome information was reviewed and stratified into eight categories according to whether the karyotype or sonographic information agreed or disagreed with sequencing results. RESULTS: Of 67 cases with fetal or neonatal karyotypes available, 16 (24%) were partially or fully concordant with the NIPT result, 4 (6%) had aneuploidy on a reference chromosome, and 47 (70%) had normal fetal chromosomes, in which 5/47 had maternal malignancies reported. One case of maternal mosaic trisomy 8 was also detected. Of cases with no fetal karyotype information, ten had an abnormal clinical outcome, one was a normal live birth, and one reported maternal malignancy. CONCLUSIONS: Noninvasive prenatal test results of autosomal monosomy or multiple aneuploidies are rare but have a diversity of underlying biologic causes. Some reflect the fetal karyotype; some reflect the presence of other maternal or fetal chromosome abnormalities, and a small number are linked to maternal disease.

Trastornos neurológicos graves y malformaciones en una niña con monosomía del cromosoma 21 / Severe neurological disorders and malformations in a girl with mo- nosomía of the chromosome 21

Se presenta el caso de una niña de 7 años de edad, que fue remitida a la Consulta de Asesoramiento Genético, por presentar malformaciones congénitas severas y rasgos dismórficos, asociado a un retardo del neurodesarrollo. Al nacer se diagnosticó una comunicación interauricular, lo cual fue corregido mediante operación cardiaca. Se le realizó estudio por técnicas de citogenética convencional obteniéndose como resultado una monosomía del cromosoma 21. El estudio de citogenética molecular por técnica FISH detectó una inserción de la zona crítica del 21 en la región subtelomérica del 6p.

The case of a 7-year-old girl is showed. She was referral to the Genetic Advice Session, for presenting severe congenital malformations and dysmorphisms, associated with a neurological delay. A canal inter auricle was diagnosed at birth, which was corrected through heart surgery. The conventional cytogenetic analyzed showed a 21 chromosome monosomy. The study of molecular cytogenetic detected an insertion of the critical region of 21 in the subteloméric 6p region.

Accurate, fast and cost-effective diagnostic test for monosomy 1p36 using real-time quantitative PCR.

Monosomy 1p36 is considered the most common subtelomeric deletion syndrome in humans and it accounts for 0.5-0.7% of all the cases of idiopathic intellectual disability. The molecular diagnosis is often made by microarray-based comparative genomic hybridization (aCGH), which has the drawback of being a high-cost technique. However, patients with classic monosomy 1p36 share some typical clinical characteristics that, together with its common prevalence, justify the development of a less expensive, targeted diagnostic method. In this study, we developed a simple, rapid, and inexpensive real-time quantitative PCR (qPCR) assay for targeted diagnosis of monosomy 1p36, easily accessible for low-budget laboratories in developing countries. For this, we have chosen two target genes which are deleted in the majority of patients with monosomy 1p36: PRKCZ and SKI. In total, 39 patients previously diagnosed with monosomy 1p36 by aCGH, fluorescent in situ hybridization (FISH), and/or multiplex ligation-dependent probe amplification (MLPA) all tested positive on our qPCR assay. By simultaneously using these two genes we have been able to detect 1p36 deletions with 100% sensitivity and 100% specificity. We conclude that qPCR of PRKCZ and SKI is a fast and accurate diagnostic test for monosomy 1p36, costing less than 10 US dollars in reagent costs.

Size-based molecular diagnostics using plasma DNA for noninvasive prenatal testing.

Noninvasive prenatal testing using fetal DNA in maternal plasma is an actively researched area. The current generation of tests using massively parallel sequencing is based on counting plasma DNA sequences originating from different genomic regions. In this study, we explored a different approach that is based on the use of DNA fragment size as a diagnostic parameter. This approach is dependent on the fact that circulating fetal DNA molecules are generally shorter than the corresponding maternal DNA molecules. First, we performed plasma DNA size analysis using paired-end massively parallel sequencing and microchip-based capillary electrophoresis. We demonstrated that the fetal DNA fraction in maternal plasma could be deduced from the overall size distribution of maternal plasma DNA. The fetal DNA fraction is a critical parameter affecting the accuracy of noninvasive prenatal testing using maternal plasma DNA. Second, we showed that fetal chromosomal aneuploidy could be detected by observing an aberrant proportion of short fragments from an aneuploid chromosome in the paired-end sequencing data. Using this approach, we detected fetal trisomy 21 and trisomy 18 with 100% sensitivity (T21: 36/36; T18: 27/27) and 100% specificity (non-T21: 88/88; non-T18: 97/97). For trisomy 13, the sensitivity and specificity were 95.2% (20/21) and 99% (102/103), respectively. For monosomy X, the sensitivity and specificity were both 100% (10/10 and 8/8). Thus, this study establishes the principle of size-based molecular diagnostics using plasma DNA. This approach has potential applications beyond noninvasive prenatal testing to areas such as oncology and transplantation monitoring.

A pregnancy with discordant fetal and placental chromosome 18 aneuploidies revealed by invasive and noninvasive prenatal diagnosis.

This study investigated a pregnancy where the fetus was diagnosed with monosomy 18p by invasive amniocentesis and karyotyping. Additional noninvasive prenatal diagnosis, which detects fetal chromosome abnormalities in the circulating cell-free plasma DNA originating from the placenta revealed a related 18p monosomy/18q trisomy, suggesting confined placental mosaicism. Based on recent observations of chromosomal instability in the early preimplantation embryo, this study speculates on the possible embryonic origin(s) of these related but discordant chromosome 18 aneuploidies in the placental and fetal tissues. The findings highlight the potential for both false-positive and -negative noninvasive prenatal diagnosis results in pregnancies where there is either confined placental mosaicism or placental mosaicism. The study investigated a pregnancy involving a fetus with a chromosome disease syndrome called monosomy 18p where part of the short arm of chromosome 18 was missing in the fetal tissues. Using non-invasive prenatal diagnosis which detects fetal chromosome abnormalities in the circulating cell free plasma DNA originating from the placenta, we also detected monosomy 18p as well a related chromosome 18 abnormality involving duplication of the long arm of chromosome 18. This suggested confined placental mosaicism where the constitution of the chromosomes are different between fetal and placental tissues. We speculated that these related chromosome 18 abnormalities arose during preimplantation embryo development, leading to the formation of different chromosome abnormalities observed in the placental and fetal tissues of this pregnancy. Our findings highlight the potential for both false positive and negative non-invasive prenatal diagnosis test results in pregnancies where there is confined placental mosaicism.

Evaluation of chromogenic in situ hybridization for the determination of monosomy 3 in uveal melanoma.

CONTEXT: Loss of 1 copy of chromosome 3 is considered a significant indicator of metastatic dissemination in uveal melanoma. Fresh or paraffin-embedded tumor tissue is most commonly used for current cytogenetic techniques for determining chromosome 3 status in uveal melanoma and often requires referral to an external specialist laboratory for analysis. OBJECTIVES: To assess the chromogenic in situ hybridization assay for detecting chromosome 3 alterations using frozen tumor imprints and to compare the results obtained with those obtained by standard fluorescence in situ hybridization or single-nucleotide polymorphism array techniques. DESIGN: Chromogenic in situ hybridization was performed on 52 frozen uveal melanoma tumor imprints. The genetic status of 26 of the 52 cases had been determined previously by fluorescence in situ hybridization (group 1); the status of 26 cases had been determined using single-nucleotide polymorphism array (group 2). RESULTS: Chromogenic in situ hybridization was successfully performed on 48 of 52 tumor imprints. Chromogenic in situ hybridization showed excellent agreement in all 24 cases determined by fluorescence in situ hybridization (100% concordance; κ = 1; P < .001; 95% confidence interval, 100%-100%), and disagreed in 4 of the 24 cases previously studied by single-nucleotide polymorphism array (83% concordance; κ = 0.67; P < .001; 95% confidence interval, 95%-39%). All 4 discordant cases were classified as disomic for chromosome 3 by chromogenic in situ hybridization and monosomic by SNP array. On histologic examination, the 4 discordant cases corresponded to 2 mixed cell tumors and 2 spindle cell tumors. CONCLUSIONS: Chromogenic in situ hybridization using tumor imprints is a reliable technique for determining chromosome 3 status in uveal melanoma. Furthermore, it can also be easily integrated into a routine histopathology laboratory.