A 600 kb triplication in the cat eye syndrome critical region causes anorectal, renal and preauricular anomalies in a three-generation family

Overlapping Spectrum of Craniofacial Microsomia Phenotype in Cat-Eye Syndrome

This study reports three patients with Cat-eye Syndrome (CES), two of which present a previous clinical diagnosis of Craniofacial microsomia (CFM). Chromosomal microarray analysis (CMA) revealed a tetrasomy of 1,7 Mb at the 22q11.2q11.21 region, which is the typical region triplicated in the CES, in all patients. The most frequent craniofacial features found in individuals with CFM and CES are preauricular tags and/or pits and mandibular hypoplasia. We reinforce that the candidate genes for CFM features, particularly ear malformation, preauricular tags/pits, and facial asymmetry, can be in the proximal region of the 22q11.2 region.

Cat eye syndrome: Clinical, cytogenetics and familial findings in a large cohort of 43 patients highlighting the importance of congenital heart disease and inherited cases

Cat Eye Syndrome (CES) is a rare genetic disease caused by the presence of a small supernumerary marker chromosome derived from chromosome 22, which results in a partial tetrasomy of 22p-22q11.21. CES is classically defined by association of iris coloboma, anal atresia, and preauricular tags or pits, with high clinical and genetic heterogeneity. We conducted an international retrospective study of patients carrying genomic gain in the 22q11.21 chromosomal region upstream from LCR22-A identified using FISH, MLPA, and/or array-CGH. We report a cohort of 43 CES cases. We highlight that the clinical triad represents no more than 50% of cases. However, only 16% of CES patients presented with the three signs of the triad and 9% not present any of these three signs. We also highlight the importance of other impairments: cardiac anomalies are one of the major signs of CES (51% of cases), and high frequency of intellectual disability (47%). Ocular motility defects (45%), abdominal malformations (44%), ophthalmologic malformations (35%), and genitourinary tract defects (32%) are other frequent clinical features. We observed that sSMC is the most frequent chromosomal anomaly (91%) and we highlight the high prevalence of mosaic cases (40%) and the unexpectedly high prevalence of parental transmission of sSMC (23%). Most often, the transmitting parent has mild or absent features and carries the mosaic marker at a very low rate (<10%). These data allow us to better delineate the clinical phenotype associated with CES, which must be taken into account in the cytogenetic testing for this syndrome. These findings draw attention to the need for genetic counseling and the risk of recurrence.

Cat eye syndrome caused by 22q11.1q11.21 duplication: case report in a Chinese family

PURPOSE

 This paper presents a report on two uncommon instances of cat eye syndrome in a Chinese family.

CASE PRESENTATION

The proband, a 23-year-old female, exhibited a diminutive cornea and complete blindness in her right eye, and the uncorrected distance visual acuity of her left eye was 0.7 LogMAR. Peripheral blood chromosome karyotyping reveal a karyotype of 47, XX, + mar. Subsequent analysis of chromosome copy number variation unveiled a 1.5 Mb duplication in the 22q11.1q11.21 region of the proband. The proband's mother,aged 49, displayed small eyes, wide-set eyes, downward slanting eyelids, and congenital heart disease. Chromosome copy number variation analysis also showed a 1.55 Mb duplication in the 22q11.1q11.21 region of chromosome 22 in the proband's mother. Ultimately, both members of this family were diagnosed with cat eye syndrome.

CONCLUSION

 Cat eye syndrome is a rare genetic disorder that greatly affects patients' lives and requires personalized treatment. This study provides new evidence for a better understanding of the diagnosis of cat eye syndrome and emphasizes the importance of genetic counseling and supervision.

Auricular fistula: a review of its clinical manifestations, genetics, and treatments

Auricular fistula is a common congenital auricular malformation, characterized as a small opening in the skin and a subcutaneous cyst. It can be classified in different ways according to positions of pits and directions of fistula tracts. The term preauricular fistula and variant type of preauricular fistula (postauricular fistula) are used. Auricular fistula prevalence varies in countries and populations, and its actual prevalence is presently unknown. The most accepted and widely cited theory of auricular fistula etiopathogenesis is an incorrect or incomplete fusion of six auricular hillocks that are mesenchymal proliferations. Auricular fistula can occur either sporadically or genetically. The pattern in inherited cases is thought to be incomplete autosomal dominant, with variable expressions, reduced penetrance, and inapparent gender differences. Auricular fistula has several forms and is reported as being a component of many syndromes. In the field of genetics, currently, there is no related review to comprehensively summarize the genetic basis of auricular fistula and related disorders. This article provides a comprehensive review of auricular fistula, especially congenital preauricular fistula, which accounts for the majority of auricular fistula, by summarizing the clinical manifestations, histological and embryological development, genetics, examinations, and treatments, as well as syndromes with auricular fistula.

A new association of Oculoauriculovertebral spectrum and persistent fifth aortic arch -double lumen aorta: a case report

Background

Oculo-auriculo-vertebral spectrum is a heterogeneous group of genetic disorder, also known as Goldenhar Syndrome, which has several phenotypic features including craniofacial anomalies, cardiac, vertebral and central nervous system defects. Cardiovascular anomalies include ventricular septal defects, atrial septal defects, patent ductus arteriosus, Tetralogy of Fallot, double outlet right ventricle, aberrant right subclavian artery, coarctation of aorta, transposition of the great arteries, double inlet left ventricle, cor triatriatum, pulmonary artery stenosis, aortic stenosis, persistent left superior vena cava, partially or totally abnormal pulmonary venous return and bicuspid aortic valve. Persistent fifth aortic arch, also named as double lumen aortic arch, is a very rare cardivascular anomaly and usually associate other cardiac defects.

Case presentation

We present a 7 month old patient with oculo-auriculo-vertebral spectrum signs as facial asymmetry, short neck, choanal atresia, cleft palate, bilateral preauricular skin tags, bilateral hypoplastic ear lobes, epibulbar dermoid cyst, rib, vertebrae and cardiovascular anomalies. Cardiovascular anomalies detected with echocardiography and computed tomography were malalignment ventricular septal defect and double lumen aorta, known as persistent fifth aortic arch.

Conclusion

Various cardiovascular anomalies may accompany Goldenhar Syndrome. We present a case with persistent fifth aortic arch and Oculo-auriculo-vertebral spectrum and this is a new association that was not reported before in the literature.

Sequencing of a Chinese tetralogy of fallot cohort reveals clustering mutations in myogenic heart progenitors

Tetralogy of Fallot (TOF) is the most common cyanotic heart defect, yet the underlying genetic mechanisms remain poorly understood. Here, we performed whole-genome sequencing analysis on 146 nonsyndromic TOF parent-offspring trios of Chinese ethnicity. Comparison of de novo variants and recessive genotypes of this data set with data from a European cohort identified both overlapping and potentially novel gene loci and revealed differential functional enrichment between cohorts. To assess the impact of these mutations on early cardiac development, we integrated single-cell and spatial transcriptomics of early human heart development with our genetic findings. We discovered that the candidate gene expression was enriched in the myogenic progenitors of the cardiac outflow tract. Moreover, subsets of the candidate genes were found in specific gene coexpression modules along the cardiomyocyte differentiation trajectory. These integrative functional analyses help dissect the pathogenesis of TOF, revealing cellular hotspots in early heart development resulting in cardiac malformations.

A child with cat-eye syndrome and oculo-auriculo-vertebral spectrum phenotype: A discussion around molecular cytogenetic findings

Cat eye syndrome (CES) is a rare chromosomal disorder that may be evident at birth. A small supernumerary chromosome is present, frequently has 2 centromeres, is bisatellited, and represents an inv dup(22)(q11) in those affected. It's known that the 22q11 region is associated with disorders involving higher and lower gene dosages. Conditions such as CES, 22q11 microduplication syndrome (Dup22q11) and oculoauriculovertebral spectrum phenotype (OAVS) may share genes belonging to this same region, which is known to have a predisposition to chromosomal rearrangements. The conditions, besides being related to chromosome 22, also share similar phenotypes. Here we have added a molecular evaluation update and results found of the first patient described with CES and OAVS phenotype, trying to explain the potential mechanism involved in the occurrence of this association.

Cecr2 mutant mice as a model for human cat eye syndrome

Cat eye syndrome (CES), a human genetic disorder caused by the inverted duplication of a region on chromosome 22, has been known since the late 1890s. Despite the significant impact this disorder has on affected individuals, models for CES have not been produced due to the difficulty of effectively duplicating the corresponding chromosome region in an animal model. However, the study of phenotypes associated with individual genes in this region such as CECR2 may shed light on the etiology of CES. In this study we have shown that deleterious loss of function mutations in mouse Cecr2 effectively demonstrate many of the abnormal features present in human patients with CES, including coloboma and specific skeletal, kidney and heart defects. Beyond phenotypic analyses we have demonstrated the importance of utilizing multiple genetic backgrounds to study disease models, as we see major differences in penetrance of Cecr2-related abnormal phenotype between mouse strains, reminiscent of the variability in the human syndrome. These findings suggest that Cecr2 is involved in the abnormal features of CES and that Cecr2 mice can be used as a model system to study the wide range of phenotypes present in CES.

Prenatal diagnosis and molecular cytogenetic identification of small supernumerary marker chromosomes: analysis of three prenatal cases using chromosome microarray analysis

Small supernumerary marker chromosomes cannot be accurately identified by G-banding, and the related phenotypes vary greatly. It is essential to specify the origin, size, and gene content of marker chromosomes using molecular cytogenetic techniques. Herein, three fetuses with de novo marker chromosomes were initially identified by G-banding. Single nucleotide polymorphism array and fluorescence in situ hybridization were performed to characterize the origins of the marker chromosomes. The karyotypes of the three fetuses were 47,XY,+mar, 46,X,+mar[32]/45,X[68], and 45,X[62]/46,X,+mar[9]. In case 1, the karyotype was confirmed as 47,XY,+ idic(22)(q11.2). Therefore, the sSMC originated from chromosome 22 and was associated with cat eye syndrome. In case 2, the marker chromosome derived from ring chromosome X, and the karyotype was interpreted as 45,X[68]/46,X,+r(X)(p11.1q21.31)[32]. Meanwhile, the karyotype of case 3 was defined as 45,X[62]/46,X,idic(Y)(q11.2) and the marker chromosome originated from chromosome Y. Case 1 continued the pregnancy, whereas the other two pregnancies underwent elective termination. The detailed characterization of marker chromosomes can facilitate informed decision making, prevent uncertainty, and provide proper prognostic assessments. Our findings emphasize the importance for combining cytogenetic and molecular genetic techniques in marker chromosome characterization.

Whole-exome sequencing in the molecular diagnosis of individuals with congenital anomalies of the kidney and urinary tract and identification of a new causative gene

Purpose

To investigate the utility of whole-exome sequencing (WES) to define a molecular diagnosis in patients clinically diagnosed with congenital anomalies of kidney and urinary tract (CAKUT).

Methods

WES was performed in 62 families with CAKUT. WES data were analyzed for Single Nucleotide Variants (SNVs) in 35 known CAKUT genes, putatively deleterious sequence changes in new candidate genes, and potentially disease-associated copy-number variants (CNVs).

Results

In approximately 5% of families, pathogenic SNVs were identified in PAX2, HNF1B, and EYA1. Observed phenotypes in these families expand the current understanding about the role of these genes in CAKUT. Four pathogenic CNVs were also identified using two CNV detection tools. In addition, we found one deleterious de novo SNV in FOXP1 among the 62 families with CAKUT. Database of clinical BMGL laboratory was queried and seven additional unrelated individuals with novel de novo SNVs in FOXP1 were identified. Six of these 8 individuals with FOXP1 SNVs, have syndromic urinary tract defects, implicating this gene in urinary tract development.

Conclusion

We conclude that WES can be used to identify the molecular etiology (SNVs, CNVs) in a subset of individuals with CAKUT. WES can also help identify novel CAKUT genes.

Origin-Dependent Inverted-Repeat Amplification: Tests of a Model for Inverted DNA Amplification

DNA replication errors are a major driver of evolution—from single nucleotide polymorphisms to large-scale copy number variations (CNVs). Here we test a specific replication-based model to explain the generation of interstitial, inverted triplications. While no genetic information is lost, the novel inversion junctions and increased copy number of the included sequences create the potential for adaptive phenotypes. The model—Origin-Dependent Inverted-Repeat Amplification (ODIRA)—proposes that a replication error at pre-existing short, interrupted, inverted repeats in genomic sequences generates an extrachromosomal, inverted dimeric, autonomously replicating intermediate; subsequent genomic integration of the dimer yields this class of CNV without loss of distal chromosomal sequences. We used a combination of in vitro and in vivo approaches to test the feasibility of the proposed replication error and its downstream consequences on chromosome structure in the yeast Saccharomyces cerevisiae. We show that the proposed replication error—the ligation of leading and lagging nascent strands to create “closed” forks—can occur in vitro at short, interrupted inverted repeats. The removal of molecules with two closed forks results in a hairpin-capped linear duplex that we show replicates in vivo to create an inverted, dimeric plasmid that subsequently integrates into the genome by homologous recombination, creating an inverted triplication. While other models have been proposed to explain inverted triplications and their derivatives, our model can also explain the generation of human, de novo, inverted amplicons that have a 2:1 mixture of sequences from both homologues of a single parent—a feature readily explained by a plasmid intermediate that arises from one homologue and integrates into the other homologue prior to meiosis. Our tests of key features of ODIRA lend support to this mechanism and suggest further avenues of enquiry to unravel the origins of interstitial, inverted CNVs pivotal in human health and evolution.

Chromosomal aberration such as gene amplification is a common event in human diseases and is often selected during adaptation of microorganism to stress. We proposed a replication-based model to explain the formation of a particular type of genomic aberration: internal inverted DNA amplification with retention of the distal end of the chromosome. In this study, using yeast as a model, we test the feasibility of several of these steps for the formation of an inverted amplification: a specific DNA replication anomaly (1) leading to the formation of a palindromic extrachromosomal circular molecule (2) followed by the homologous reintegration of this molecule into the genome (3). A significant feature of this mode of amplification is that the amplified sequences contain one or more replication origins. The instability of the inverted junctions can lead, through homology driven processes, to more complex genomic structures that contain a partial triplication within a duplicated segment, a structure commonly found associated with human disease.

Growth hormone deficiency and pituitary malformation in a recurrent Cat-Eye syndrome: a family report

Growth hormone deficiency affects roughly between one in 3000 and one in 4000 children with most instances of growth hormone deficiency being idiopathic. Growth hormone deficiency can also be associated with genetic diseases or chromosome abnormalities. Association of growth hormone deficiency together with hypothalamic-pituitary axis malformation and Cat-Eye syndrome is a very rare condition. We report a family with two brothers presenting with growth delay due to a growth hormone deficiency associated with a polymalformation syndrome. They both displayed pre-auricular pits and tags, imperforate anus and Duane retraction syndrome. Both parents and a third unaffected son displayed normal growth pattern. Cerebral MRI showed a hypothalamic-pituitary axis malformation in the two affected brothers. Cytogenetic studies revealed a type I small supernumerary marker chromosome derived from chromosome 22 resulting in a tetrasomy 22pter-22q11.21 characteristic of the Cat-Eye syndrome. The small supernumerary marker chromosome was present in the two affected sons and the mother in a mosaic state. Patients with short stature due to growth hormone deficiency should be evaluated for chromosomal abnormality. Family study should not be underestimated.

Typical and Atypical Associated Findings in a Group of 346 Patients with Mayer-Rokitansky-Kuester-Hauser Syndrome

STUDY OBJECTIVE

The Mayer-Rokitansky-Kuester-Hauser (MRKH) syndrome is characterized by vaginal and uterine aplasia in a 46,XX individual. Multiple abnormalities may be associated with MRKH syndrome, and it appears to overlap other syndromes. The aim of this study was to describe the spectrum of associated malformations and syndromes as well as abnormal karyotypic findings in a large cohort of 346 patients.

DESIGN, SETTING, AND PARTICIPANTS

The study is a retrospective analysis of 346 MRKH patients treated in the University Hospital in Tuebingen between 1998 and 2013.

MAIN OUTCOME MEASURES

The dataset was screened for typical associated malformations as well as atypical malformations and abnormal karyotypes. A complete review of the literature was included.

RESULTS

Among our cohort of 346 patients, we found that 53.2% had MRKH type 1, 41.3% had MRKH type 2, and 5.5% had MURCS syndrome. The group with associated malformations included 57.6% renal, 44.4% skeletal, and 30.8% other malformations. Additionally, we found 2 cases of absent radius syndrome, 3 cases of anal atresia, and 1 patient with oculodentodigital dysplasia, and other atypical malformations. Abnormal karyotypes were found in 5 cases, and 39 siblings and 11 parents had known malformations.

CONCLUSIONS

This study supports the hypothesis that the syndrome has a multifactorial pathogenesis. With the high numbers of associated malformations reported in this study, patients with MRKH syndrome should be regarded as having a complex syndrome. Molecular-genetic analyses in larger numbers of children after surrogacy, twin pregnancies, and familial cases may make it possible to obtain further information about the etiology of the syndrome.

Severe psychomotor delay in a severe presentation of cat-eye syndrome

Cat-eye syndrome is a rare genetic syndrome of chromosomal origin. Individuals with cat-eye syndrome are characterized by the presence of preauricular pits and/or tags, anal atresia, and iris coloboma. Many reported cases also presented with variable congenital anomalies and intellectual disability. Most patients diagnosed with CES carry a small supernumerary bisatellited marker chromosome, resulting in partial tetrasomy of 22p-22q11.21. There are two types of small supernumerary marker chromosome, depending on the breakpoint site. In a very small proportion of cases, other cytogenetic anomalies are reportedly associated with the cat-eye syndrome phenotype. Here, we report a patient with cat-eye syndrome caused by a type 1 small supernumerary marker chromosome. The phenotype was atypical and included a severe developmental delay. The use of array comparative genomic hybridization ruled out the involvement of another chromosomal imbalance in the neurological phenotype. In the literature, only a few patients with cat-eye syndrome present with a severe developmental delay, and all of the latter carried an atypical partial trisomy 22 or an uncharacterized small supernumerary marker chromosome. Hence, this is the first report of a severe neurological phenotype in cat-eye syndrome with a typical type 1 small supernumerary marker chromosome. Our observation clearly complicates prognostic assessment, particularly when cat-eye syndrome is diagnosed prenatally.

A de novo atypical ring sSMC(22) characterized by array CGH in a boy with cat-eye syndrome

BACKGROUND

Microduplications 22q11 have been characterized as a genomic duplication syndrome mediated by nonallelic homologous recombination between region-specific low-copy repeats. Here we report on a 19 years old boy with intellectual disability having an unexpected structurally complex ring small supernumerary marker chromosome (sSMC) originated from a larger trisomy and a smaller tetrasomy of proximal 22q11 harboring additional copies of cat eye syndrome critical regions genes.

RESULTS

PRINCIPAL CLINICAL FEATURES WERE: anorectal and urogenital malformations, total anomalous pulmonary venous return with secundum ASD, hearing defect, preauricular pits, seizure and eczema. The proband also presented some rare or so far not reported clinical findings such as hyperinsulinaemia, severe immunodeficiency and grave cognitive deficits. Chromosome analysis revealed a mosaic karyotype with the presence of a small ring-like marker in 60% of cells. Array CGH detected approximately an 1,2 Mb single and a 0,2 Mb double copy gain of the proximal long arm of chromosome 22. The 1,3 Mb intervening region of chromosome 22 from centromere to the breakpoints showed no copy alteration. The karyotype of the patient was defined as 47,XY,+mar[60]/46,XY[40].ish idic r(22)(q11.1.q11.21) × 4.arr 22q11(17,435, 645-18,656,678) × 3,(17,598,642-17,799,783) × 4 dn.

CONCLUSIONS

The present report is the first one with a detailed description of clinical presentation in a patient carrying an atypical size ring sSMC (22) analyzed by array CGH. The specialty of the finding is emphasized by the fact that although the patient had a mosaic sSMC and the amplified region was smaller than in typical cat eye syndrome cases, the clinical presentation was severe.

Hemifacial microsomia in cat-eye syndrome: 22q11.1-q11.21 as candidate loci for facial symmetry

Cat-Eye syndrome (CES), (OMIM 115470) also known as chromosome 22 partial tetrasomy or inverted duplicated 22q11, was first reported by Haab [1879] based on the primary features of eye coloboma and anal atresia. However, >60% of the patients lack these primary features. Here, we present a 9-month-old female who at birth was noted to have multiple defects, including facial asymmetry with asymmetric retrognathia, bilateral mandibular hypoplasia, branchial cleft sinus, right-sided muscular torticollis, esotropia, and an atretic right ear canal with low-to-moderate sensorineural hearing loss, bilateral preauricular ear tag/pits, and two skin tags on her left cheek. There were no signs of any colobomas or anal atresia. Hemifacial microsomia (HFM) was suspected clinically. Chromosome studies and FISH identified an extra marker originated from 22q11 consistent with CES, and this was confirmed by aCGH. This report expands the phenotypic variability of CES and includes partial tetrasomy of 22q11.1-q11.21 in the differential diagnosis of HFM. In addition, our case as well as the previous association of 22q11.2 deletions and duplications with facial asymmetry and features of HFM, supports the hypothesis that this chromosome region harbors genes important in the regulation of body plan symmetry, and in particular facial harmony.

Prenatal diagnosis and molecular cytogenetic characterization of mosaicism for a small supernumerary marker chromosome derived from chromosome 22 associated with cat eye syndrome

We present prenatal diagnosis of mosaicism for a small supernumerary marker chromosome (sSMC) derived from chromosome 22 associated with cat eye syndrome (CES) using cultured amniocytes in a pregnancy with fetal microcephaly, intrauterine growth restriction, left renal hypoplasia, total anomalous pulmonary venous return with dominant right heart and right ear deformity. The sSMC was bisatellited and dicentric, and was characterized by multiplex ligation-dependent probe amplification (MLPA) and array comparative genomic hybridization (aCGH). The SALSA MLPA P250-B1 DiGeorge Probemix showed duplication of gene dosage in the CES region. aCGH showed a 1.26-Mb duplication at 22q11.1-q11.21 encompassing CECR1-CECR7. The sSMC was likely inv dup(22) (q11.21). Prenatal diagnosis of an sSMC(22) at amniocentesis should alert CES. MLPA, aCGH and fetal ultrasound are useful for rapid diagnosis of CES in case of prenatally detected sSMC(22).

Clinical geneticists' views of VACTERL/VATER association

VACTERL association (sometimes termed "VATER association" depending on which component features are included) is typically defined by the presence of at least three of the following congenital malformations, which tend to statistically co-occur in affected individuals: Vertebral anomalies, Anal atresia, Cardiac malformations, Tracheo-Esophageal fistula, Renal anomalies, and Limb abnormalities. Although the clinical criteria for VACTERL association may appear to be straightforward, there is wide variability in the way clinical geneticists define the disorder and the genetic testing strategy they use when confronted with an affected patient. In order to describe this variability and determine the most commonly used definitions and testing modalities, we present the results of survey responses by 121 clinical geneticists. We discuss the results of the survey responses, provide a literature review and commentary from a group of physicians who are currently involved in clinical and laboratory-based research on VACTERL association, and offer an algorithm for genetic testing in patients with this association.

A de novo sSMC(22) Characterized by High-Resolution Arrays in a Girl with Cat-Eye Syndrome without Coloboma

Cat-eye syndrome (CES) results from trisomy or tetrasomy of proximal 22q originated by a small supernumerary marker chromosome (sSMC). Two critical regions for the major clinical features of CES (CESCRs) have been suggested; however, CES clinical presentation often does not correlate with the sSMC genetic content. We report here a CES girl without coloboma and carrier of a de novo type I sSMC(22) as determined by G- and C-banding, NOR staining and microarrays. This sSMC included 6 distal genes outside the original CESCR and led to a tetrasomy for 22q11.1-22q11.21. The patient's final karyotype was 47,XX,+psu dic(22)(q11.21).arr 22q11.1q11.21(15,250,000-17,035,860)×4 dn. The amplified region outside of CESCR included some genes that may be related to neurologic, heart and renal abnormalities. Conversely, even though the amplification included the CECR2 gene, a major candidate for eye features, there was no coloboma in the patient. The genetic delineation of the present sSMC further strengthens that the CES clinical presentation does not fit completely with the duplicated genetic content and that CES is actually a genomic disorder. Furthermore, since we observed no mosaicism, we believe that other mechanisms might be behind the variability of CES phenotypes as well, mainly those related with functional interactions among amplified genes.