Deep Phenotyping and Genetic Characterization of a Cohort of 70 Individuals With 5p Minus Syndrome

Establishment and characterization of Cri Du Chat neuronal stem cells: a novel promising resource to study the syndrome

The Cri Du Chat (CdC) Syndrome is a rare chromosome disease condition resulting from variable size deletion occurring on the short arm of one of the chromosomes 5. This disorder, which affects one in 50,000 births, is responsible for developmental retardation, the mechanism of which has remained unexplained. TERT, SEMA5 A, CTNND2, TPPP, mapped in chromosome 5 short arm, are known to be expressed in the brain, and to play a role in the development of the nervous system, oligodentrocytes and in the regulation of glutamatergic and dopaminergic synaptic transmission. It is critical to understand how their haploinsufficiency might affect the development and presentation of the disease. In the absence of an animal model and of significant accessible, human tissue, human pluripotent stem cells (iPSC) directly reprogrammed from patient somatic cells open a new area of disease modeling as they can virtually be differentiated into any cell type. Our study reports, for the first time, the generation of neuronal stem cells (NSCs) from CdC-iPSCs line and in addition, subsequent differentiation into a heterogeneous population of neurons. Gene expression of the mentioned and single copy deleted genes was also evaluated by comparing their expression level in iPSC, NSCs and neuron lines. The present research represents the first and the most innovative approach, to create an in vitro CdC neuronal model to have a new translational framework to study the pathologic processes.

Insufficient gene expression and lost gene regulatory network may underlie the mechanism of Hirschsprung Disease in 5p-syndrome

Cri-du-chat syndrome (CDC, OMIM 123450) is a rare chromosomal syndrome that results from partial deletions on the short arm of chromosome 5, known as 5p minus. Substantial clinical and genetic heterogeneity were observed in CDC patients. Large efforts have been dedicated to correlating the deleted regions on 5p arm with observed symptoms in CDC patients. However, the genetic basis of many specific phenotypes, including the co-occurrence of Hirschsprung Disease (HSCR), have yet been clarified. Here, we conducted a study on two patients with CDC and HSCR using whole genome sequencing (WGS) analyses. Our WGS data confirmed the deletion regions on 5p associated with CDC and indicated potential unknown genetic mechanisms underlying HSCR. On the one hand, leveraging human single-cell atlas for developing enteric nervous system, we demonstrated that some affected genes in these two patients overlapped with those showing expression changes along the development pseudotime of enteric nervous cells (ENC) and overlapped with known HSCR genes including RET, NRG1, ERBB (ERBB2 and ERBB3), ITGB (ITGB1). On the other hand, integrating gene regulatory relationship estimated from single cell chromatin accessibility omics of enteric neurons, we found that the 5p deletion regions contained key cis-regulatory regions for HSCR-related gene GDNF. Taken together, our study reveals the genetic basis of HSCR or intestinal phenotypes in 5p minus patients, highlighting the importance of studying gene regulatory relationships to explain phenotypic heterogeneity.

From phenotype to phonotype: a comprehensive description of voice features of Cri du chat syndrome

Genetic syndromes have been studied by extensive research allowing a better definition of their clinical manifestations, natural history, and etiopathogenetic mechanisms. Nevertheless, some relevant, but still unexplored aspects of these multisystemic conditions need to be clarified. One of these aspects is the characterization of the vocal production, especially in some genetic syndromes in which the distinctive voice is the hallmark of the syndrome (e.g., Cri du chat syndrome, CdCS). The aim of this study is to provide a detailed description of phonotype of patients affected by CdCS. We prospectively recorded and analysed acoustical features of three corner vowels [a], [i], and [u] and number listing from 1 to 10 of 29 patients with molecularly confirmed CdCS (age range 4-21 years; mean 11 ± 6; median 10 years). For perceptual analysis, the GIRBAS scale was completed. The acoustical analysis was performed through BioVoice software. When stratified by age and gender, in the older men subgroup the grade, roughness, and asthenia mean values are the highest for each vowel, when compared with values of the same parameters obtained in the other subgroups. Statistical analysis highlighted 26 significant differences: 38% (10) concern the sustained phonation of /a/, 27% (7) are related to /i/ whereas 19% (5) to /u/. Ratio1, Ratio2, VSA, and FCR were also significant. Conclusion: The voice production not only conveys linguistic and paralinguistic information but also can give information regarding the speaker's biological and clinical characteristics.

Case Report: An association of left ventricular outflow tract obstruction with 5p deletions

Introduction

5p deletion syndrome, also called Cri-du-chat syndrome 5p is a rare genetic syndrome with reports up to 36% of patients are associated with congenital heart defects. We investigated the association between left outflow tract obstruction and Cri-du-chat syndrome.

Methods

A retrospective review of the abnormal microarray cases with congenital heart defects in Children's Hospital of Pittsburgh and the Cytogenomics of Cardiovascular Malformations Consortium.

Results

A retrospective review at nine pediatric centers identified 4 patients with 5p deletions and left outflow tract obstruction (LVOTO). Three of these patients had additional copy number variants. We present data suggesting an association of LVOTO with 5p deletion with high mortality in the presence of additional copy number variants.

Conclusion

A rare combination of 5p deletion and left ventricular outflow obstruction was observed in the registry of copy number variants and congenital heart defects.

Pleomorphic Parotid Adenoma in a Child Affected with Cri du Chat Syndrome: Clinical, Cytogenetic, and Molecular Analysis

Salivary gland pleomorphic adenoma (SGPA) is the most common type of benign epithelial tumor; it is observed more commonly in females (with a female-to-male ratio of 1.43:1), and the age at diagnosis ranges between 40 and 59 years, with only 2% of cases diagnosed before age 18. Cri du Chat (CdC) is a rare syndrome caused by deletions of various sizes in the short arm of chromosome 5. Tumors in CdC patients are extremely rare: in Danish, Spanish, Australian, and Japanese groups of cases, no tumors have been reported, while a few cases have been described among 321 CdC patients collected in Italy and Germany. These cases all involve tumors that appear at a young age. We here report the case of a parotid pleomorphic adenoma in an 8-year-old boy with CdC. Exome analysis did not identify variants certainly significant for the development of SGPA. A CGH array, analyzed both in peripheral blood and tumor samples, failed to recognize anomalies previously associated with SGPA but identified a de novo duplication in 7p15.2, which contains part of a gene, SKAP2, in which the increased copy number is associated with the development of a different type of tumor such as pancreatic duct adenocarcinoma. The assumption that the duplication in 7p15.2 is relevant for the development of SGPA in our patient implies that CGH array studies must be included early in life in routine work-ups of CdC to identify CNVs with possible pathogenic roles for tumor development. This is particularly also relevant in relation to the severely impaired possibility for patients with CdC to report discomfort or pain related to tumor development. Constitutional CNVs in addition to the deletion in 5p should also be extensively studied to verify if their presence in some patients could explain why, in these cases, tumors develop at an age younger than expected.

Esophageal Cancer with Early Onset in a Patient with Cri du Chat Syndrome

BACKGROUND

In Cri du Chat (CdC), cancer as comorbidity is extremely rare. In databases from Denmark, Spain, Australia, New Zealand, and Japan, no cancer was reported; in Italy and Germany, four cancers were identified out of 321 CdCs.

METHODS

In a 29-year-old CdC patient, clinical investigations following hematemesis led to the diagnosis of esophageal adenocarcinoma (EAC). A high pain threshold was also observed. Conventional and molecular cytogenetic defined the size of the deletion, and exome analysis on the trio completed the molecular work.

RESULTS

Cytogenetic analysis showed a de novo chromosomal alteration: 46,XY,ishdel(5)(p14.3)(D5S28-) and arr[GRCh37] 5p15.33p14.3(1498180_19955760)x1. A quantitative sensory test demonstrated a high heat threshold. A 18f-fluorodeoxyglucose PET/TC scan of the brain failed to detect reduction of metabolism in the somatosensory area or insular cortex. Exome analysis in the trio (patient and parents) failed to identify variants to be interpreted as a likely risk factor for EAC.

CONCLUSION

We conclude that the presence of well-known risk factors (maleness, obesity, gastroesophageal reflux, and Barrett's metaplasia) in a patient with very limited capability of expressing discomfort or referring clinical symptoms have been the main risk factors for developing EAC. At present, based on the available data, there is no evidence of any increased risk of developing cancer in CdC patients.

Chromosomal Microarray in Patients with Non-Syndromic Autism Spectrum Disorders in the Clinical Routine of a Tertiary Hospital

Autism spectrum disorders (ASD) comprise a group of neurodevelopmental disorders (NDD) characterized by deficits in communication and social interaction, as well as repetitive and restrictive behaviors, etc. The genetic implications of ASD have been widely documented, and numerous genes have been associated with it. The use of chromosomal microarray analysis (CMA) has proven to be a rapid and effective method for detecting both small and large deletions and duplications associated with ASD. In this article, we present the implementation of CMA as a first-tier test in our clinical laboratory for patients with primary ASD over a prospective period of four years. The cohort was composed of 212 individuals over 3 years of age, who met DSM-5 diagnostic criteria for ASD. The use of a customized array-CGH (comparative genomic hybridization) design (KaryoArray®) found 99 individuals (45.20%) with copy number variants (CNVs); 34 of them carried deletions (34.34%) and 65 duplications (65.65%). A total of 28 of 212 patients had pathogenic or likely pathogenic CNVs, representing approximately 13% of the cohort. In turn, 28 out of 212 (approximately 12%) had variants of uncertain clinical significance (VUS). Our findings involve clinically significant CNVs, known to cause ASD (syndromic and non-syndromic), and other CNVs previously related to other comorbidities such as epilepsy or intellectual disability (ID). Lastly, we observed new rearrangements that will enhance the information available and the collection of genes associated with this disorder. Our data also highlight that CMA could be very useful in diagnosing patients with essential/primary autism, and demonstrate the existence of substantial genetic and clinical heterogeneity in non-syndromic ASD individuals, underscoring the continued challenge for genetic laboratories in terms of its molecular diagnosis.

5p deletion with congenital diaphragmatic hernia: a case report

Background

5p deletion syndrome is known as cri-du-chat syndrome, but there are no reports on congenital diaphragmatic hernia complications associated with it.

Case presentation

A 28-year-old primigravida Japanese woman was referred for 5 mm of nuchal translucency. Fetal growth restriction was found at 20 weeks, and a left-sided congenital diaphragmatic hernia was diagnosed at 24 weeks. The karyotype of the fetus was diagnosed as 46, XX, del(5)(p14) and referred to our hospital. At 36 ^+ 6 weeks, a 1524 g female infant was delivered after premature membrane rupture, with Apgar scores of 4 and 6 at 1 and 5 minutes, respectively. The baby was intubated immediately with sedation and muscle relaxation, after birth for initial treatment for congenital diaphragmatic hernia. The peripheral blood karyotype was consistent with the prenatal result. The infant was discharged alive, without any respiratory support, after the defect of the diaphragm was repaired.

Conclusion

The results of this study may be helpful for antenatal genetic counseling.