Pallister–Killian syndrome: Cytogenetics and molecular investigations of mosaic tetrasomy 12p in prenatal chorionic villus and in amniocytes. Strategy of prenatal diagnosis

Abstract Objective Pallister–Killian syndrome (PKS) is a rare, sporadic genetic disorder caused by mosaic tetrasomy of the short arm of chromosome 12 (12p). Clinically, PKS is characterized by several systemic abnormalities, such as intellectual impairment, hearing loss, epilepsy, hypotonia, craniofacial dysmorphism, pigmentary skin anomalies, epilepsy, and a variety of congenital malformations. Prenatally, PKS can be suspected in the presence of ultrasound anomalies: diaphragmatic hernia, rhizomelic micromelia, hydrops fetalis, fetal overweight, ventriculomegaly in the central nervous system, congenital heart defects, or absent visualization of the stomach. In all these cases, a detailed genetic study is required. PKS is diagnosed by prenatal genetic analysis through chorionic villus sampling, genetic amniocentesis, and cordocentesis. Case Report We report two cases of PKS with prenatal diagnosis of isochromosome 12p made by cytogenetic studies. The first case is of a 36-year-old pregnant woman who underwent genetic chorionic villus sampling at 13 th weeks of gestation after 1 st trimester prenatal ultrasound revealed clinical features of PKS: flat nasal bridge and fetal hydrops. The second case is of a 32-year-old pregnant woman with genetic amniocentesis at 17 th weeks of gestation that showed mos46,XX[21]/47,XX,+i(12p) associated to PKS. Conclusion New molecular cytogenetic techniques array comparative genomic hybridization and fluorescence in-situ hybridization in association with conventional karyotype are pivotal innovative tools to search for chromosomic anomalies and for a complete prenatal diagnosis, especially in cases such as PKS where array comparative genomic hybridization analysis alone could not show mosaicism of i(12p)

Analisi epidemiologica sull’immunità da SARS-CoV-2 in un campione di soggetti residenti nella capitale romana

In the present study, we analyzed results from two rapid tests to evaluate the serological response to SARS-CoV-2 to assess the percentage of patients exposed to this viral infection and their relative humoral response status. The assessment of SARS-CoV-2 seroprevalence is essential for defining the epidemiological parameters of COVID-19 disease. We analyzed data from 617 subjects from the geographical area of Rome that underwent a rapid test to detect SARS-CoV-2 antibodies. Thirty-one out of 617 samples were positive. Among these, 90% (28/31) were positive for both IgM and IgG, while 3% (1/31) were positive for IgG only and 7% (2/31) for IgM only. We conclude that the prevalence of SARS-CoV-2 antibodies in this specific geographic area was 5% (31/617) in the first week of April, and that 0.16% (1/617) of the analyzed subjects were carrying acquired immunity, as indicated by the presence of IgG only. While limited to the area of Rome, this study proves the possibility for better understanding the progression of this pandemic through the use of antibody titers.   Keywords: COVID-19, SARS-CoV-2 virus, IgM, IgG antibodies.Nel presente lavoro, abbiamo analizzato i risultati derivanti dall’uso di due test rapidi per la valutazione della risposta anticorpale al virus SARS-CoV-2, con lo scopo di verificarne la percentuale di soggetti esposti all’infezione e lo stato di immunità per l’infezione da virus SARS-CoV-2. Valutazioni relative alla sieroprevalenza del COVID-19 sono importanti per definire i parametri epidemiologici di questa malattia. Abbiamo analizzato quindi i dati derivanti da 617 soggetti, residenti nell’ area geografica di Roma, sottoposti a test rapido in grado di rilevare la presenza di anticorpi specifici di classe IgM ed IgG diretti verso il virus SARS-CoV-2. Sono risultati positivi al test 31 su 617 campioni analizzati: il 90 % (28/31) era positivo sia alle IgM che alle IgG, mentre il 3% (1/31) era positivo alle sole IgG, ed il 7 % (2/31) alle sole IgM. Possiamo concludere che la prevalenza degli anticorpi anti-SARS-CoV-2 nell’area geografica considerata era del 5% (31/617). Mentre si osserva che al momento solo lo 0.16% (1/617) dei soggetti è portatore di una immunità acquisita indicata dalla presenza delle sole IgG. Lo studio, anche se limitato nella sola capitale romana dimostra la possibilità di stimare e meglio comprendere la progressione di questa pandemia.   Parole chiave: COVID-19, SARS-CoV-2 virus, anticorpi IgM, Ig

A case report of a meiotic segregation study on a small supernumerary marker chromosome

Small supernumerary marker chromosomes (sSMCs) have been described from all human chromosomes with different sizes and shapes. However, it is difficult to know the clinical manifestations associated with them, because such knowledge depends on the size, presence of euchromatic material, degree of mosaicism and/or uniparental disomy (UPD)

Next Generation Sequencing Approach in a Prenatal Case of Cardio-Facio-Cutaneus Syndrome

Cardiofaciocutaneous syndrome (CFCS) belongs to a group of developmental disorders due to defects in the Ras/Mitogen-Activated Protein Kinase (RAS/MAPK) signaling pathway named RASophaties. While postnatal presentation of these disorders is well known, the prenatal and neonatal characteristics are less recognized. Noonan syndrome, Costello syndrome, and CFCS diagnosis should be considered in pregnancies with a normal karyotype and in the case of ultrasound findings such as increased nuchal translucency, polyhydramnios, macrosomia and cardiac defect. Because all the RASopathies share similar clinical features, their molecular characterization is complex, time consuming and expensive. Here we report a case of CFCS prenatally diagnosed through Next Generation Prenatal Diagnosis (NGPD), a new targeted approach that allows us to concurrently investigate all the genes involved in the RASophaties

Evaluation of SARS-CoV-2 viral RNA in fecal samples

The need for timely establishment of a complete diagnostic protocol of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is demanded worldwide. We selected 15 positive novel coronavirus disease 19 (COVID-19) patients with mild or no symptom. Initially, fecal samples were negative in the 67% (10/15) of the cases, while 33% (5/10) of the cases were positive. After serial virus RNA testing, 73% (11/15) of the cases resulted positive to fecal specimens. In particular, 15 days after the first positive respiratory specimens test, 6 fecal specimens became positive for SARS-CoV-2 RNA, while 13 respiratory test returned negative result. In conclusion, qRT-PCR assays of fecal specimens, is an important step to control infection, suggesting that samples remained positive for SARS-CoV-2 RNA longer time then respiratory tract samples. Our results enhance the recent knowledge on this emerging infectious disease and offer suggestions for a more complete diagnostic strategy

A Rapid and Consistent Method to Identify Four SARS-CoV-2 Variants during the First Half of 2021 by RT-PCR

Since 2020, the COVID-19 pandemic has spread worldwide, causing health, economic, and social distress. Containment strategies rely on rapid and consistent methodology for molecular detection and characterization. Emerging variants of concern (VOCs) are currently associated with increased infectivity and immune escape (natural defence mechanisms and vaccine). Several VOCs have been detected, including Alpha variant (B.1.1.7), Beta variant (B.1.351), Gamma variant (P.1/B.1.1.28.1) and Delta variant (B.1.617.2), first identified in the UK, South Africa, Brazil and India, respectively. Here, a rapid and low-cost technique was validated to distinguish the Alpha, Beta, Gamma, and Delta SARS-CoV-2 variants by detecting spike gene mutations using a real-time reverse transcription polymerase chain reaction methodology (RT-PCR). A total of 132 positive patients affected by coronavirus disease-19 (COVID-19) were analysed by employing RT-PCR to target single-nucleotide polymorphisms (SNPs) to screen spike protein mutations. All data were validated by the next-generation sequencing (NGS) methodology and using sequences from a public database. Among 132 COVID-19-positive samples, we were able to discriminate all of the investigated SARS-CoV-2 variants with 100% concordance when compared with the NGS method. RT-PCR -based assays for identifying circulating VOCs of SARS-CoV-2 resulted in a rapid method used to identify specific SARS-CoV-2 variants, allowing for a better survey of the spread of the virus and its transmissibility in the pandemic phase

Discordance between karyotype from amniotic fluid and postnatal lymphocyte cultures

Discordance between karyotype seen from amniocentesis and from neonatal blood is a very unusual condition with different possible causes. We present a case of discordance between prenatal cytogenetic diagnosis from amniotic fluid and postnatal cytogenetic diagnosis from lymphocyte cultures

Proteomic analysis for the study of amniotic fluid protein composition

Amniotic fluid (AF), routinely used for prenatal diagnosis, contains large amounts of proteins produced by the amnion epithelial cells, fetal tissues, fetal excretions and placental tissues. Although many amniotic fluid proteins have been identified and are currently used to detect potential fetal anomalies, little is known about the functions of these proteins and how they interact with one another. Identification of changes in the protein content of amniotic fluid, therefore, may be used to detect a particular type of pathology, or to ascertain a specific genetic disorder. In the present work we used a proteomic approach, combining 2DE and MS, in order to study the protein composition of AFS