Distal 8p deletion (8)(p23.1): an easily missed chromosomal abnormality that may be associated with congenital heart defect and mental retardation

A novel genotype-phenotype between persistent-cloaca-related VACTERL and mutations of 8p23 and 12q23.1

The mechanism underlying anorectal malformations (ARMs)-related VACTERL (vertebral defects, anal atresia, cardiac defects, tracheo-esophageal fistula, and renal and limb abnormalities) remains unclear. Copy number variation (CNV) contributed to VACTERL pathogenicity. Here, we report a novel CNV in 8p23 and 12q23.1 identified in a case of ARMs-related VACTERL association. This 12-year-old girl presented a cloaca (urethra, vagina, and rectum opening together and sharing a single tube length), an isolated kidney, and a perpetuation of the left superior vena cava at birth. Her intelligence, growth, and development were slightly lower than those of normal children of the same age. Array comparative genomic hybridization revealed a 9.6-Mb deletion in 8p23.1-23.3 and a 0.52-Mb duplication in 12q23.1 in her genome. Furthermore, we reviewed the cases involving CNVs in patients with VACTERL, 8p23 deletion, and 12q23.1 duplication, and our case was the first displaying ARMs-related VACTERL association with CNV in 8p23 and 12q23.1. These findings enriched our understanding between VACTERL association and the mutations of 8p23 deletion and 12q23.1 duplication. IMPACT: This is a novel case of a Chinese girl with anorectal malformations (ARMs)-related VACTERL with an 8p23.1-23.3 deletion and 12q23.1 duplication. Cloaca malformation is presented with novel copy number variation in 8p23.1-23.3 deletion and 12q23.1 duplication.

Expanding the Phenotype of 8p23.1 Deletion Syndrome: Eight New Cases Resembling the Clinical Spectrum of 22q11.2 Microdeletion

OBJECTIVE

To report the effectiveness of early molecular diagnosis in the clinical management of rare diseases, presenting 8 patients with 8p23.1DS who have clinical features that overlap the phenotypic spectrum of 22q11.2DS.

STUDY DESIGN

This report is part of a previous study that aims to provide a precocious molecular diagnosis of the 22q11.2 deletion syndrome in 118 infants with congenital heart disease. To confirm the clinical diagnosis, patients underwent comparative genomic screening by the multiplex ligation-dependent probe amplification (MLPA) assay with the SALSA MLPA probemix kits P064-B2, P036-E1, P070-B2, P356-A1, and P250- B1. Subsequently, the patients performed the genomic microarray using the Infinium CytoSNP-850K BeadChip to confirm the deletion, determine the breakpoints of the deletion, and search for genomic copy number variations.

RESULTS

MLPA performed with 3 different kits revealed the 8p23.1 typical deletion involving the PPP1R3B, MSRA, and GATA4 genes in the 5 patients. The array analysis was performed on these 5 patients and 3 other patients (8 patients) who also had clinical suspicion of 22q11 deletion (8 patients) allowed a precise definition of the breakpoints and excluded other genomic abnormalities.

CONCLUSIONS

Cytogenomic screening was efficient in establishing a differential diagnosis and ruling out the presence of other concomitant syndromes. The clinical picture of the 8p23.1 deletion syndrome is challenging; however, cytogenomic tools can provide an exact diagnosis and help to clarify the genotype-phenotype complexity of these patients. Our reports underline the importance of early diagnosis and clinical follow-up of microdeletion syndromes.

A Cytogenetic Study of Turkish Children with Global Developmental Delay

Global developmental delay (GDD)/intellectual disability (ID) is common in children and its etiology is unknown in many cases. Chromosomal abnormalities are predominant genetic causes of GDD/ID. The aim of this study is to determine the genetic risk factors that may be involved in the etiology of GDD/ID. In this study, 810 children with moderate to severe, clinically unexplained GDD/ID for whom cytogenetic analysis were performed were retrospectively rescreened. The results showed that GDD/ID affected more females than males (2 girls:1 boy). A total of 54 children (6.7%) with GDD showed chromosomal aberrations (CAs): 59.3% of these CAs were structural aberrations, and the rest were numerical aberrations (40.7%). Specifically, inversions, deletions, and reciprocal and robertsonian translocations, which were detected in 1, 0.7, 0.8, and 0.4% of the children, respectively, constituted important categories of structural CAs. Among numerical CAs, classic Turner and mosaics were detected in 1.2% of all children. Trisomy 21 and mosaic trisomy 21 were detected in 1% of the children. Marker chromosomes and 47,XXY karyotypes were found in two children each. Our results suggest that female sex is more affected by CAs among GDD/ID cases, and cytogenetic analysis is useful in the etiological diagnosis of GDD/ID.

8p23.1 deletion: Look out for left ventricular hypertrabeculation and not only congenital heart diseases. Single-center experience and literature revision

Deletions involving the distal portion of the short arm of chromosome 8(8p23.1) show a high phenotypic variability. Congenital heart diseases (CHD) are often described. GATA4 when mutated or deleted is reported to be involved in cardiac morphogenesis. Only twice, left ventricular non compaction (LVNC) was reported in literature in association with 8p23.1 deletion. The present cohort includes five new patients with 8p23.1 deletions including GATA4. The spectrum of CHD is variable. Moreover, in four patients, LV hypertrabeculation was detected and in the fifth LVNC was recognized. Literature revision identified 45 patients with 8p23.1 deletions (encompassing GATA4) and heart involvement. It included wide spectrum of CHD including: heterotaxy spectrum 7/45 (15, 6%), atrioventricular canal 14/45 (balanced 3/45 including two of them with hypoplastic aortic arch; unbalanced 4/45, Fallot-AVC 1/45, partial AVC 3/45, unspecified 3/45), predominant major left heart lesions included 2/45 (4, 4%): interrupted aortic arch and hypoplastic left heart syndrome. Left ventricular hypertrabeculation might be potentially underestimated in patients with 8p23.1 deletion. These might suggest the importance of including microarray analysis in this group of patients. Moreover, 8p23.1 microdeletion or GATA4 variants can be considered in heterotaxy genetic panels.

Investigação Citogenômica de Crianças com Doença Cardíaca Congênita: Experiência de um Centro no Brasil

Fundamento

Algumas síndromes têm características específicas e facilmente reconhecíveis, enquanto outras podem ser mais complexas de se identificar e podem apresentar diferentes manifestações fenotípicas, por exemplo. Um diagnóstico etiológico é importante para entender a natureza da doença, para estabelecer o prognóstico e para começar o tratamento, permitindo a inclusão de pacientes na sociedade e reduzindo o custo financeiro dessas doenças.

Objetivo

A proposta inicial deste estudo foi a triagem citogenética para detectar a síndrome de deleção 22q11.2 (SD22q11.2) em recém-nascidos e crianças com doença cardíaca congênita utilizando a técnica da amplificação multiplex de sondas dependente de ligação (MLPA). Assim, por meio da pesquisa, outras mudanças genômicas foram identificadas nesses pacientes cardíacos. Nosso objetivo se estendeu a investigar essas outras mudanças citogenéticas.

Métodos

Investigamos 118 recém-nascidos com doenças cardíacas congênitas nascidos consecutivamente durante um ano, utilizando a técnica da MLPA.

Resultados

A técnica da MLPA permitiu a detecção da SD22q11.2 em 10/118 pacientes (8,5%). Outras alterações genômicas foram identificadas em 6/118 pacientes (5%): 1p36 del, 8p23 del (2 casos), 7q dup, 12 dup e 8q24 dup.

Conclusão

Este estudo ressalta a relevância da detecção de alterações genômicas que estão presentes em recém-nascidos e crianças com doenças cardíacas congênitas por meio de ferramentas citogenômicas.

Reproductive History of a Woman With 8p and 18p Genetic Imbalance and Minor Phenotypic Abnormalities

We report on the phenotype and the reproductive history of an adult female patient with an unbalanced karyotype: 8p23 and 18p11.3 terminal deletions and 8p22 duplication. The indication for karyotyping of the 28-year-old patient was a structural rearrangement in her miscarriage specimen: 45,ХХ,der(8;18)t(8;18)(p23;p11.3). Unexpectedly, the patient had the same karyotype with only one normal chromosome 8, one normal chromosome 18, and a derivative chromosome, which was a product of chromosomes 8 and 18 fusion with loss of their short arm terminal regions. Fluorescence in situ hybridization revealed that derivative chromosome was a pseudodicentric with an active centromere of chromosome 8. Array comparative genomic hybridization confirmed 8p and 18p terminal deletions and additionally revealed 8p22 duplication with a total of 43 OMIM annotated genes being affected by the rearrangement. The patient had minor facial and cranial dysmorphia and no pronounced physical or mental abnormalities. She was socially normal, had higher education and had been married since the age of 26 years. Considering genetic counseling, the patient had decided to conceive the next pregnancy through in vitro fertilization (IVF) with preimplantation genetic testing for structural chromosomal aberrations (PGT-SR). She underwent four IVF/PGT-SR cycles with a total of 25 oocytes obtained and a total of 10 embryos analyzed. Only one embryo was balanced regarding chromosomes 8 and 18, while the others were unbalanced and demonstrated different combinations of the normal chromosomes 8 and 18 and the derivative chromosome. The balanced embryo was transferred, but the pregnancy was not registered. After four unsuccessful IVF/PGT-SR cycles, the patient conceived naturally. Non-invasive prenatal testing showed additional chromosome 18. The prenatal cytogenetic analysis of chorionic villi revealed an abnormal karyotype: 46,ХХ,der(8;18)t(8;18)(p23;p11.3)mat,+18. The pregnancy was terminated for medical reasons. The patient has a strong intention to conceive a karyotypically normal fetus. However, genetic counseling regarding this issue is highly challenging. Taking into account a very low chance of balanced gametes, emotional stress caused by numerous unsuccessful attempts to conceive a balanced embryo and increasing age of the patient, an IVF cycle with a donor oocyte should probably be considered.

Is interstitial 8p23 microdeletion responsible of 46,XY gonadal dysgenesis? One case report from birth to puberty

BACKGROUND

Chromosome 8p deletions are associated with a variety of conditions, including cardiac abnormalities, mental, behavioral problems with variable morphotype and genitourinary anomalies in boys.

METHODS

We describe the follow-up over almost 15 years of a boy who initially presented with perineal hypospadias with a micropenis and cryptorchidism with 46,XY DSD.

RESULTS

Imaging, pathology, and hormonal exploration suggested gonadal dysgenesis. Further genetic studies were deemed necessary during follow-up. The child's further development recommended further genetic analyses. High-resolution analysis showed an interstitial deletion on the short arm of a chromosome 8: 46,XY,del(8)(p23.1p23.1). We reviewed the literature and found 102 cases including 54 boys: 62.7% had mental problems, 50.9% a dysmorphic disorder, 55.9% cardiac anomalies, and 46.3% of the boys had genitourinary anomalies. Our patient's genital abnormalities can be explained by the haploinsufficiency of the genes, such as GATA4 (OMIM 600576) that are included in the deleted area.

CONCLUSION

This case of severe 46,XY DSD raises the question of the role played by 8p23 microdeletion in gonadal dysgenesis. Clinicians are encouraged to look for this anomaly on chromosome 8 in cases of unexplained gonadal dysgenesis even when few signs suggestive of this anomaly are present.

Single Cell Transcriptomics Reveal Abnormalities in Neurosensory Patterning of the Chd7 Mutant Mouse Ear

The chromatin remodeling protein CHD7 is critical for proper formation of the mammalian inner ear. Humans with heterozygous pathogenic variants in CHD7 exhibit CHARGE syndrome, characterized by hearing loss and inner ear dysplasia, including abnormalities of the semicircular canals and Mondini malformations. Chd7^Gt/+ heterozygous null mutant mice also exhibit dysplastic semicircular canals and hearing loss. Prior studies have demonstrated that reduced Chd7 dosage in the ear disrupts expression of genes involved in morphogenesis and neurogenesis, yet the relationships between these changes in gene expression and otic patterning are not well understood. Here, we sought to define roles for CHD7 in global regulation of gene expression and patterning in the developing mouse ear. Using single-cell multiplex qRT-PCR, we analyzed expression of 192 genes in FAC sorted cells from Pax2Cre;mT/mGFP wild type and Chd7^Gt/+ mutant microdissected mouse otocysts. We found that Chd7 haploinsufficient otocysts exhibit a relative enrichment of cells adopting a neuroblast (vs. otic) transcriptional identity compared with wild type. Additionally, we uncovered disruptions in pro-sensory and pro-neurogenic gene expression with Chd7 loss, including genes encoding proteins that function in Notch signaling. Our results suggest that Chd7 is required for early cell fate decisions in the developing ear that involve highly specific aspects of otic patterning and differentiation.

Terminal 13p deletion in squirrel monkey (Saimiri sciureus) with differentiated phenotype

BACKGROUND

The taxonomic classification of squirrel monkeys is often controversial issue offering many different information. The classification of captive animals is difficult due to the phenotypic similarities between the presented species, which is observed mainly in coat coloration.

METHODS

The objective of this study was to analyze the chromosome pattern of one squirrel monkey with off standard physical characteristics, which is kept in the Laboratory Animals Breeding Center in Rio de Janeiro State, Brazil, and try to establish some correlations. Chromosomes were obtained using lymphocyte culture technique.

RESULTS AND CONCLUSIONS

Evaluation of G bands showed a terminal deletion in one chromosome of pair 13. The association of the results found with the different phenotypic characteristics led us to classify it as a Saimiri sciureus specimen with a structural chromosomal change, possibly allowing the expression of hemizygous alleles.

Analysis of chromosomal abnormalities by CGH-array in patients with dysmorphic and intellectual disability with normal karyotype

Objective

To investigate chromosomal abnormalities by CGH-array in patients with dysmorphic features and intellectual disability with normal conventional karyotype.

Methods

Retrospective study, carried out from January 2012 to February 2014, analyzing the CGH-array results of 39 patients.

Results

Twenty-six (66.7%) patients had normal results and 13 (33.3%) showed abnormal results - in that, 6 (15.4%) had pathogenic variants, 6 (15.4%) variants designated as uncertain and 1 (2.5%) non-pathogenic variants.

Conclusion

The characterization of the genetic profile by CGH-array in patients with intellectual disability and dysmorphic features enabled making etiologic diagnosis, followed by genetic counseling for families and specific treatment.

Microarray Analysis of 8p23.1 Deletion in New Patients with Atypical Phenotypical Traits

We describe two patients carrying deletions of chromosome 8p23.1 with a commonly critical region identified by means of oligonucleotide array comparative genomic hybridization (array CGH). They didn't present congenital heart defects or behavioral problems. Only one patient presented with intellectual disability and carrying deletion of TNKS gene. We presumed the inclusion of TNKS gene in the mental impairment.

Molecular cytogenetic characterization and genotype/phenotype analysis in a patient with a de novo 8p23.2p23.3 deletion/12p13.31p13.33 duplication

Genomic copy number imbalances are being increasingly identified as an important cause of intellectual disability (ID) and behavioral disturbances. This article reports the clinical features, and long term follow-up of a patient with neurodevelopmental, cognitive, and behavioral abnormalities associated with facial dysmorphism, CNS anomalies, and epilepsy. The karyotype was normal; array CGH testing revealed a de novo cryptic aberration with a terminal 8p23.2p23.3 deletion, and a concomitant 12p13.31p13.33 duplication, of 6.86 Mb, and 8.49 Mb, respectively. Our patient clinical features are compared to those of partial 8 monosomy and/or partial 12p trisomy cases reported in literature, in order to establish genotype-phenotype correlations. For some features, for example, electroencephalogram (EEG) abnormalities and epilepsy, both abnormalities seem to make a contribution, while most phenotypic traits have been assigned to 8p monosomy or to 12p trisomy, contributing to a tentative phenotype map for partial monosomy of the short arm of chromosome 8, and trisomy of the short arm of chromosome 12.

Dextrocardia, atrial septal defect, severe developmental delay, facial anomalies, and supernumerary ribs in a child with a complex unbalanced 8;22 translocation including partial 8p duplication

We report on a child with dextrocardia, atrial septal defect (ASD), severe developmental delay, hypotonia, 13 pairs of ribs, left preauricular choristoma, hirsutism, and craniofacial abnormalities. Prenatal cytogenetic evaluation showed karyotype 46,XY,?dup(8p)ish del(8)pter. Postnatal array CGH demonstrated a 6.8 Mb terminal deletion at 8p23.3-p23, an interstitial 31.1 Mb duplication within 8p23.1-p11, and a terminal duplication of 0.24 Mb at 22q13.33, refining the karyotype to 46,XY,der(8)dup(8)(p23.1p11.1)t(8;22)(p23.1;q13.1).ish der(8)dup(8)(p23.1p11.1)t(8;22)(p23.1;q13.1) (D8S504-,MS607 + ,ARSA + ,D8Z1 + , RP115713 + +). Previous reports of distal 8p deletion, 8p duplication, and distal 22q duplication have shown similar manifestations, including congenital heart disease, intellectual impairment, and multiple minor anomalies. We correlate the patient's clinical findings with these particular areas of copy number. This case study supports the use of aCGH to identify subtle chromosomal rearrangement in infants with cardiac malformation as their most significant or only apparent birth defect. Additionally, it illustrates why aCGH is essential in the description of chromosome rearrangements, even those seemingly visible via routine karyotype. This method shows that there is often greater complexity submicroscopically, essential to an adequate understanding of a patient's genotype and phenotype.

8p deletion and 9p duplication in two children with electrical status epilepticus in sleep syndrome

We describe two individuals with the same chromosomal aberrations derived from an unbalanced translocation between chromosomes 8p and 9p, who presented with intellectual disabilities, dysmorphic features, and localization-related epilepsy. Several years after the onset of epilepsy, aggravation of widespread epileptic discharges during sleep resulted in the emergence of absence and/or atonic seizures in both patients; one patient additionally presented with psychomotor deterioration. These symptoms completely disappeared after treatment with ethosuximide and benzodiazepines, and marked improvement was observed in electroencephalographic findings. We review the clinical features of der(8)t(8;9) with particular focus on epileptic complications. We conclude that particular types of chromosomal aberrations may have a propensity to develop the condition categorized as electrical status epilepticus in sleep.

Genotype-phenotype association studies of chromosome 8p inverted duplication deletion syndrome

Individuals diagnosed with chromosome 8p inverted duplication deletion (invdupdel(8p)) manifest a wide range of clinical features and cognitive impairment. The purpose of this study is to employ array CGH technology to define more precisely the cytogenetic breakpoints and regions of copy number variation found in several individuals with invdupdel(8p), and compare these results with their neuropsychological characteristics. We examined the cognitive-behavioral features of two male and two female children, ages 3-15 years, with invdupdel(8p). We noted cognitive deficits that ranged from mild to severe, and adaptive behavior composites that ranged from significantly to substantially lower than adequate levels. CARS scores, a measure of autistic behavior, identified three children with autism or autistic-like features. Three of the four children exhibited attention deficits and hyperactivity consistent with a DSM-IV-TR diagnosis of ADHD. One child showed extreme emotional lability. Interestingly, intellectual disability was not correlated with deletion size, nor was the deletion location associated with the autistic phenotype. On the other hand, the duplication length in 8p21.1/8p22 was associated with cognitive deficit. In addition, a small locus of over-expression in 8p21.3 was common for all three participants diagnosed as autistic. A limitation of the study is its small sample size. Further analyses of the deleted and over-expressed regions are needed to ascertain the genes involved in cognitive function and, possibly, autism.

Subtelomeric rearrangements and copy number variations in people with intellectual disabilities

BACKGROUND

The most prevalent type of structural variation in the human genome is represented by copy number variations that can affect transcription levels, sequence, structure and function of genes.

METHOD

In the present study, we used the multiplex ligation-dependent probe amplification (MLPA) technique and quantitative PCR for the detection of copy number variation in 132 intellectually disabled male patients with normal karyotypes and negative fragile-X-testing.

RESULTS

Ten of these patients (7.6%) showed copy number variation in the subtelomeric regions, including deletions and duplications.

DISCUSSION

Duplications of the SECTM1 gene, located at 17q25.3, and of the FLJ22115 gene, located at 20p13, could be associated with phenotype alterations. This study highlights the relevance in the aetiology of intellectual disability of subtelomeric rearrangements that can be screened by MLPA and other molecular techniques.

Submicroscopic subtelomeric aberrations in Chinese patients with unexplained developmental delay/mental retardation

BACKGROUND

Subtelomeric imbalance is widely accepted as related to developmental delay/mental retardation (DD/MR). Fine mapping of aberrations in gene-enriched subtelomeric regions provides essential clues for localizing critical regions, and provides a strategy for identifying new candidate genes. To date, no large-scale study has been conducted on subtelomeric aberrations in DD/MR patients in mainland China.

METHODS

This study included 451 Chinese children with moderate to severe clinically unexplained DD/MR. The subtelomere-MLPA (multiplex ligation dependent probe amplification) and Affymetrix human SNP array 6.0 were used to determine the subtelomeric copy number variations. The exact size and the breakpoint of each identified aberration were well defined.

RESULTS

The submicroscopic subtelomeric aberrations were identified in 23 patients, with a detection rate of 5.1%. 16 patients had simple deletions, 2 had simple duplications and 5 with both deletions and duplications. The deletions involved 14 different subtelomeric regions (1p, 2p, 4p, 6p, 7p, 7q, 8p, 9p, 10p, 11q, 14q, 15q, 16p and 22q), and duplications involved 7 subtelomeric regions (3q, 4p, 6q, 7p, 8p, 12p and 22q). Of all the subtelomeric aberrations found in Chinese subjects, the most common was 4p16.3 deletion. The sizes of the deletions varied from 0.6 Mb to 12 Mb, with 5-143 genes inside. Duplicated regions were 0.26 Mb to 11 Mb, with 6-202 genes inside. In this study, four deleted subtelomeric regions and one duplicated region were smaller than any other previously reported, specifically the deletions in 11q25, 8p23.3, 7q36.3, 14q32.33, and the duplication in 22q13. Candidate genes inside each region were proposed.

CONCLUSIONS

Submicroscopic subtelomeric aberrations were detected in 5.1% of Chinese children with clinically unexplained DD/MR. Four deleted subtelomeric regions and one duplicated region found in this study were smaller than any previously reported, which will be helpful for further defining the candidate dosage sensitive gene associated with DD/MR.

Chromosome 8p23.1 deletions as a cause of complex congenital heart defects and diaphragmatic hernia

Recurrent interstitial deletion of a region of 8p23.1 flanked by the low copy repeats 8p-OR-REPD and 8p-OR-REPP is associated with a spectrum of anomalies that can include congenital heart malformations and congenital diaphragmatic hernia (CDH). Haploinsufficiency of GATA4 is thought to play a critical role in the development of these birth defects. We describe two individuals and a monozygotic twin pair discordant for anterior CDH all of whom have complex congenital heart defects caused by this recurrent interstitial deletion as demonstrated by array comparative genomic hybridization. To better define the genotype/phenotype relationships associated with alterations of genes on 8p23.1, we review the spectrum of congenital heart and diaphragmatic defects that have been reported in individuals with isolated GATA4 mutations and interstitial, terminal, and complex chromosomal rearrangements involving the 8p23.1 region. Our findings allow us to clearly define the CDH minimal deleted region on chromosome 8p23.1 and suggest that haploinsufficiency of other genes, in addition to GATA4, may play a role in the severe cardiac and diaphragmatic defects associated with 8p23.1 deletions. These findings also underscore the importance of conducting a careful cytogenetic/molecular analysis of the 8p23.1 region in all prenatal and postnatal cases involving congenital defects of the heart and/or diaphragm.

Congenital neuroblastoma in a patient with partial trisomy of 2p

We report the fourth example of a patient with germline partial trisomy of 2p21-pter and congenital neuroblastoma. The male infant had a dysmorphic facial expression and presented with congenital heart disease, supernumerary nipples, hypospadias, shawl scrotum, hemilateral persistent hyperplastic primary vitreous, and neuroblastoma. His germline karyotype of 46,XY,der(8)t(2;8)(p21;p23.2) was inherited from a maternal-balanced translocation, which indicates that the proto-oncogene MYCN region of 2p24.3 is tripicated in germline cells. A cytogenetic study of the biopsied tumor cells did not show MYCN amplification, but the DNA index was 2.4 and histologic fluorescent in situ hybridization analysis indicated somatic mutation with near-pentaploidy of the tumor cells. This could be an alternative mechanism of MYCN activation in the process of the tumorigenesis of neuroblastoma.

Prenatal diagnosis ofde novo deletions of 8p23.1 or 15q26.1 in two fetuses with diaphragmatic hernia and congenital heart defects

OBJECTIVE

To show the importance of using high-resolution chromosome analysis and FISH-technique for finding subtle chromosomal lesions in prenatal diagnosis specially when there are abnormal ultrasound findings.

METHODS

Ecographic examination of the fetus. GTG banded chromosome and FISH analysis using subtelomeric probes on amniocytes.

RESULTS

We report two prenatal cases with congenital diaphragmatic hernia (CDH) and congenital heart defects (CHDs) with different deletions confirmed by FISH: del(8)(p23.1p23.1) and del(15)(q26.1).

CONCLUSION

These cases support the evidence that the regions 15q26.1 and 8p23.1 may play an important role in the development of the diaphragm. A deletion 8p23.1 or 15q26.1 should be considered whenever a CDH and/or a cardiac abnormality are detected on ultrasound.

Trisomy 3q25.1-qter and monosomy 8p23.1-pter in a patient: cytogenetic and molecular analysis with delineation of the phenotype

We describe a 4-year-old boy with partial 3q trisomy and distal 8p monosomy. The patient presented with mental retardation, dysmorphic face, congenital heart defect, brain and genital anomalies, and behavioral problems. The conventional cytogenetic analysis showed a 46,XY,add(8p) karyotype. Reverse painting and microsatellite analysis demonstrated a partial monosomy of 8p23.1 --> pter and a partial trisomy of 3q25.1 --> qter. The data suggest that the chromosomal rearrangement originated from a de novo translocation in a paternal germinal cell. The phenotype observed in our patient resulted from the combination of those defects described in the isolated dup(3q) and distal del(8p) syndromes.

A Girl with Pervasive Developmental Disorder and Complex Chromosome Rearrangement Involving 8p and 10p

We report a 4-year-old girl with a de novo, apparently balanced complex chromosome rearrangement. She initially presented for assessment of velopharyngeal insufficiency due to hypernasal speech. She has distinctive facial features (long face, broad nasal bridge, and protuberant ears with simplified helices), bifid uvula, strabismus, and joint laxity. She is developmentally delayed, with language and cognitive skills approximately 2 SD below the mean expected for her age, and meets ADI, ADOS, and DSM-IV criteria for pervasive developmental disorder. She has poor eye contact, atypical communication and social interaction, repetitive behaviours and significant difficulties with processing sensory input. Her karyotype is characterized by the presence of two derivative chromosomes; 46,XX, der(8)(10pter- >10pl2.32::8p12- >8qter), der(l0)(8pter- >8p21.3::10p12.32- >10p11.23::8p21.3- > 8p12::10p11.23- >l0qter). The der(8) is a result of translocation of the segment 10p12.32-pter onto 8p12. The der(l0) has two 8p segments collectively from 8p12-pter in that the segment 8p21.3-pter is translocated onto 10p12.32 and the segment 8p12-p21.3 is inserted at 10p11.23. FISH analysis showed no microdeletion of the major locus at 22q11.2 nor for the minor locus at 10p13p14. This case suggests that aberrations at 8p12, 8p21.3, 10p11.23 and/or 10p12.32 may result in pervasive developmental disorder, associated with mild cognitive delay and specific facial anomalies.

Mosaicism for an ectopic NOR at 8pter and a complex rearrangement of chromosome 8 in a patient with severe psychomotor retardation

We describe a 3-year-old girl with severe delays in mental and motor skills, a history of generalized seizures, and subtle dysmorphic features. Conventional cytogenetics revealed a mosaic karyotype. A de novo ectopic NOR at the telomeric region of the short arm of one chromosome 8 (8ps) was found in 90% of lymphocyte and in 98% of fibroblast metaphases. A small NOR-bearing marker chromosome and a large derivative chromosome 8 without short arm satellites (der(8)) were present in the remaining cells. FISH with a probe specific for centromeres 14 and 22 labeled both the telomeric region of 8ps and the small marker centromere. Der(8) included an inverted duplication of 8p and a rearranged duplication of 8q but lacked a second centromere. A subtelomeric probe for 8p revealed a cryptic deletion in 8ps and der(8). Thus, the karyotype represents a combination of submicroscopic partial monosomy 8pter and mosaic trisomy 8.

The application of region-specific probes for the resolution of duplication 8p: a case report and a review of the literature

The structural rearrangement in the short arm of a chromosome 8 in a clinically affected patient has been reinvestigated by FISH using whole chromosome painting and region specific YAC probes. An inverted duplication of the segment p22-->p11.2 and a deletion of the subtelomeric region were demonstrated. By this approach, a more detailed resolution of the duplication/deletion 8p was possible. With the application of molecular cytogenetic methods the existence of different duplication segments within the clinical entity of duplication/deficiency 8p can be shown.

Congenital diaphragmatic hernia and chromosomal anomalies: autopsy study

In a 10-year review of autopsy records from Lutheran General Hospital (1992-2002), 13 cases of congenital diaphragmatic hernia (CDH) were found. The fetuses ranged between 21 and 35 wk of gestation. Four were born alive and five were diagnosed prenatally. The defect was left-sided in 11 cases. Cytogenetic study revealed five cases with normal karyotype and three cases with complex karyotypes. In five cases, no karyotype was performed. The three complex karyotypes were: 46,XX,del(8)(p23.1), 47,XX, +i(12)(p10)[6]/46XX[14] (Pallister-Killian syndrome), and 47,XY,+der(22)t(11:22) (q23.3:q11.2). The unbalanced translocation of chromosomes 11 and 22 in congenital diaphragmatic hernia has not been previously described. Three fetuses had heart abnormalities, including one which was associated with the 8p deletion. The other two had no karyotype study. Neither in this study, nor in the literature, is there a consistent or prevailing association between a specific chromosomal anomaly and CDH. The embryologic closure of the diaphragmatic leaflets may be mediated by a nonstructural chromosomal defect, more than one gene, and/or may be related to abnormalities not currently detectable.

High intensity ras signaling induces premature senescence by activating p38 pathway in primary human fibroblasts

Although oncogenic ras plays a pivotal role in neoplastic transformation, it triggers an anti-oncogenic defense mechanism known as premature senescence in normal cells. In this study, we investigated the induction of cellular responses by different expression levels of oncogenic ras in primary human fibroblasts. We found that a moderate, severalfold increase in ras expression promoted cell growth. Further elevation of ras expression initially enhanced proliferation but eventually induced p16INK4A expression and senescence. The induction of these opposing cellular responses by ras signals of different intensity was achieved through differential activation of the MAPK pathways that mediated these responses. Whereas moderate ras activities only stimulated the mitogenic MEK-ERK pathway, high intensity ras signals induced MEK and ERK to higher levels, leading to stimulation of the MKK3/6-p38 pathway, which had been shown previously to act downstream of Ras-MEK to trigger the senescence response. Thus, these studies have revealed a mechanism for the differential effects of ras on cell proliferation. Furthermore, moderate ras activity mediated transformation in cooperation with E6E7 and hTERT, suggesting that a moderate intensity ras signal can provide sufficient oncogenic activities for tumorigenesis. This result also implies that the ability of ras to promote proliferation and oncogenic transformation can be uncoupled with that to induce senescence in cell culture and that the development of tumors with relatively low ras activities may not need to acquire genetic alterations that bypass premature senescence.

Interrupted aortic arch in a child with trisomy 5q31.1q35.1 due to a maternal (20;5) balanced insertion

Complex congenital heart defects (CHD) are associated with a variety of single gene abnormalities and chromosomal rearrangements. Of the various forms of CHD, aortic arch interruption, a conotruncal heart defect, is relatively uncommon. Here we report a male neonate with aortic arch interruption type B, secundum atrial septal defect, perimembranous ventricular septal defect, patent ductus arteriosus, aortic and subaortic stenosis, and trisomy 5q31.1q35.1 resulting from a maternal balanced insertion (20;5). Chromosomal deletions, including deletion 22q11, have been reported with interrupted aortic arch (IAA); however, to our knowledge this is the first report of a trisomy of distal chromosome 5q associated with aortic arch interruption. Here we compare this child's features to other cases of trisomy 5q31.1q35.1, and review other causes of IAA. We conclude that gene dosage in this chromosomal region likely influences aortic arch development.

Mosaic inv dup(8p) marker chromosome with stable neocentromere suggests neocentromerization is a post-zygotic event

Marker chromosomes containing active human neocentromeres have been described in individuals where the chromosomes are non-mosaic, suggesting that they are mitotically stable, but also in individuals where there is mosaicism, raising the possibility of neocentromere instability. We report two independently ascertained individuals who are mosaic for a supernumerary marker chromosome, shown by reverse chromosome painting to have an 8p origin, resulting in mosaicism for tetrasomy 8p23.1-->pter in the patient. The markers have a primary constriction but show no detectable centromeric alpha-satellite DNA. The marker in Patient 1 demonstrated no centromere protein CENP-B binding, but associated with nine different functionally critical centromere proteins. Investigation of peripheral blood lymphocytes from this patient on five separate occasions over a 13-year period showed 23-46% mosaicism for the marker chromosome with no decrease in incidence. In vitro investigation of primary and secondary sub-clones of a lymphoblast cell line derived from the patient demonstrated 100% stability of the marker chromosome indicating that neocentromere instability is unlikely to be responsible for the mosaicism in the patient. This and other available data support a general model of neocentromerization as a post-zygotic event, irrespective of whether the supernumerary chromosome fragment has arisen during meiosis or post-fertilization at mitosis.

Submicroscopic 8pter deletion, mild mental retardation, and behavioral problems caused by a familial t(8;20)(p23;p13)

Microscopically visible distal 8p deletions have been associated with growth and mental impairment, minor facial anomalies, congenital heart defects, and behavioral problems. We report two cousins with mild retardation and behavioral problems, including inappropriate sexual behavior and pyromania. Familial learning difficulties on the grandfather's side incompatible with Mendelian inheritance prompted telomere screening, which detected a submicroscopic terminal 8p deletion of < 5.1 Mb. The cousins' mothers both carried a t(8;20)(p23;p13) balanced translocation. The frequently observed microcephaly in patients with microscopically visible deletions of 8pter is lacking in both cousins, suggesting that the gene(s) causing the microcephaly is centromeric to the deleted region. The absence of cardiac defects in the cousins confirms the more proximal location of gene(s) causing these abnormalities in other reported cases with microscopically visible 8pter deletions and supports involvement of the GATA4 gene. Moreover, the current cases predict the presence of a putative gene(s) involved in behavior in the most telomeric 5.1 Mb of the p-arm of chromosome 8. This first clinical report of a submicroscopic subtelomeric 8p deletion gives more insight into the so-called 8p- syndrome and demonstrates the difficulty in making a clinical diagnosis for a submicroscopic 8pter deletion in an individual patient with mental retardation.

Familial dup(8)(p12p21.1): mild phenotypic effect and review of partial 8p duplications

We describe a family with direct transmission of a duplication of 8p12-->8p21.1. The phenotype of affected relatives included mild mental retardation but no minor anomalies. The duplication was identified by means of GTG-banding and fluorescence in situ hybridization with a probe specific for 8p12 generated by microdissection and degenerate oligonucleotide primed-polymerase chain reaction. Assay of glutathione reductase, which has been localised to 8p21.1, was significantly increased when compared with controls with normal chromosomal constitution. To the best of our knowledge, a proximal direct duplication of 8p restricted to subbands p12-->p21.1 has not been reported so far. The reported aberration is compared with other partial duplications of 8p, in particular to inversion duplications 8p and to small direct distal duplications involving 8p23.1. Am. J. Med. Genet. 94:306-310, 2000.

Deletion of a 5-cM region at chromosome 8p23 is associated with a spectrum of congenital heart defects

BACKGROUND

Cytogenetic evidence suggests that the haploinsufficiency of > or =1 gene located in 8p23 behaves as a dominant mutation, impairing heart differentiation and leading to a wide spectrum of congenital heart defects (CHDs), including conotruncal lesions, atrial septal defects, atrioventricular canal defects, and pulmonary valve stenosis. An 8p heart-defect-critical region was delineated, and the zinc finger transcription factor GATA4 was considered a likely candidate for these defects. We narrowed this region and excluded a major role of GATA4 in these CHDs.

METHODS AND RESULTS

We studied 12 patients (7 had CHD and 5 did not) with distal 8p deletions from 9 families by defining their chromosome rearrangements at the molecular level by fluorescent in situ hybridization and short-tandem repeat analysis. Subjects with 8p deletions distal to D8S1706, at approximately 10 cM from the 8p telomere, did not have CHD, whereas subjects with a deletion that included the more proximal region suffered from the spectrum of heart defects reported in patients with 8p distal deletions. The 5-cM critical region is flanked distally by D8S1706 and WI-8327, both at approximately 10 cM, and proximally by D8S1825, at 15 cM. Neither GATA4 nor angiopoietin-2 (ANGPT2; a gene in 8p23 involved in blood vessel formation) were found to be deleted in some of the critical patients. We also found that CHDs are not related to the parental origin of deletion.

CONCLUSIONS

Haploinsufficiency for a gene between WI-8327 and D8S1825 is critical for heart development. A causal relationship does not seem to exist between GATA4 and ANGPT2 haploinsufficiency and CHDs.

Subtle familial unbalanced translocation t(8;11)(p23.2;p15.5) in two fetuses with Beckwith-Wiedemann features

We describe a subtle translocation t(8;11)(p23.2;p15.5) ascertained after two induced abortions in the same sibship because of the discovery of fetal hydrops on ultrasound examination. Initial cytogenetic studies performed on cultured amniotic fluid cells were considered as normal in both fetuses. High resolution banding analysis and FISH studies performed on the parents' chromosomes revealed a paternal translocation t(8;11)(p23.2;p15.5). Retrospective FISH analysis of both fetuses showed that they carried the same chromosomal imbalance including a distal monosomy 8pter and a distal trisomy 11pter. The phenotypes of the fetuses were re-examined and found to be compatible with Beckwith-Wiedemann syndromes (BWS). FISH analysis using an IGF2 probe demonstrated the presence of three copies of the IGF2 gene. This study highlights the value of searching for subtle chromosome rearrangements in families with recurrent unexplained multiple malformation syndromes discovered prenatally. Also, it contributes to a better delineation of the prenatal phenotype of BWS. Finally, it sheds new light on the aetiology of non-immune hydrops fetalis.

Three-year-old girl with partial trisomy 4p and partial monosomy 8p with resemblance to Brachmann-de Lange syndrome--another locus for Brachmann-de Lange syndrome on 4p?

We describe a 3-year-old girl with partial trisomy 4p and partial monosomy 8p who had prenatal and postnatal growth retardation, mental retardation, no speech development, mild synophrys, hirsutism, apparently low-set ears, dysphonic hoarse voice, hyperactivity, and small hands with proximal placement of the thumbs. She had recurrent lung infections, due to earlier aspiration and immune deficiency (chronic granulomatous disease). Cytogenetic findings in this and other cases with suggestive phenotype may point to an additional locus for Brachmann-de Lange phenotype.

Cloning, sequencing, and analysis of inv8 chromosome breakpoints associated with recombinant 8 syndrome

Rec8 syndrome (also known as "recombinant 8 syndrome" and "San Luis Valley syndrome") is a chromosomal disorder found in individuals of Hispanic descent with ancestry from the San Luis Valley of southern Colorado and northern New Mexico. Affected individuals typically have mental retardation, congenital heart defects, seizures, a characteristic facial appearance, and other manifestations. The recombinant chromosome is rec(8)dup(8q)inv(8)(p23.1q22.1), and is derived from a parental pericentric inversion, inv(8)(p23.1q22.1). Here we report on the cloning, sequencing, and characterization of the 8p23.1 and 8q22 breakpoints from the inversion 8 chromosome associated with Rec8 syndrome. Analysis of the breakpoint regions indicates that they are highly repetitive. Of 6 kb surrounding the 8p23.1 breakpoint, 75% consists of repetitive gene family members-including Alu, LINE, and LTR elements-and the inversion took place in a small single-copy region flanked by repetitive elements. Analysis of 3.7 kb surrounding the 8q22 breakpoint region reveals that it is 99% repetitive and contains multiple LTR elements, and that the 8q inversion site is within one of the LTR elements.

A paternally inherited terminal deletion, del(8)(p23.1)pat, detected prenatally in an amniotic fluid sample: a review of deletion 8p23.1 cases

A subtle terminal deletion of the short arm of chromosome 8 with a breakpoint in p23.1 was detected in amniocytes. Parental chromosome studies revealed a similar deletion in the father. The fetus did not have any abnormalities in a level II ultrasound. The pregnancy was continued and resulted in the birth of a baby girl. The child was normal at six months of age and no heart murmur was detected. In a retrospective review of cases in our laboratory, four other cases with a deletion del(8)(p23.1) were found. Three were paediatric cases with microcephaly, developmental delay, ASD, VSD, pulmonic stenosis, congenital and behavioural abnormalities. One was a 29-year-old woman with a mosaic karyotype. She had a history of spontaneous abortions and no known cardiac defect. Using conventional cytogenetics and/or FISH studies with 8p telomere probe and 8 painting probe, the 8p23.1 deletions were shown to be either terminal or interstitial. The karyotype from the prenatal case was compared with the other cases of 8p23.1 deletions in our laboratory to see if there was a discernible difference in the size of the deletion. The deletion in the proband seemed to involve a more distal 8p23.1 breakpoint. In the father's high resolution chromosomes (550-850 band level) the breakpoint appeared to be 8p23.1 approximately 23.2 and FISH studies using an 8p telomeric probe confirmed a terminal deletion. Interstitial deletion of sub-band 8p23.1 was associated with phenotypic abnormalities and distal 8p23.2pter deletion was found in apparently normal individuals, therefore, 8p23.1 appears to be the critical region for clinical abnormalities.

Associations between chromosomal anomalies and congenital heart defects: a database search

Recent technical advances in molecular biology and cytogenetics, as well as a more developmental approach to congenital heart disorders (CHDs), have led to considerable progress in our understanding of their pathogenesis, especially of the important causative role of genetic factors. The complex embryology of the heart suggests the involvement of numerous genes, and hence, numerous chromosomal loci, such as the recently identified 22q11, in normal cardiomorphogenesis. In order to identify other loci, the Human Cytogenetics DataBase was searched for all chromosome anomalies associated with CHD. Through the application of several (arbitrary) criteria we have selected associations occurring so frequently that they may not be forfuituous, suggesting assignment of a gene or genes responsible for specific CHDs to certain chromosome regions. The results of this study may be a first step in the detection of specific chromosome defects responsible for CHD, which will be useful in daily patient care and may provide clues for further cytogenetic and molecular studies.

Delineation of the critical deletion region for congenital heart defects, on chromosome 8p23.1

Deletions in the distal region of chromosome 8p (del8p) are associated with congenital heart malformations. Other major manifestations include microcephaly, intrauterine growth retardation, mental retardation, and a characteristic hyperactive, impulsive behavior. We studied genotype-phenotype correlations in nine unrelated patients with a de novo del8p, by using the combination of classic cytogenetics, FISH, and the analysis of polymorphic DNA markers. With the exception of one large terminal deletion, all deletions were interstitial. In five patients, a commonly deleted region of approximately 6 Mb was present, with breakpoints clustering in the same regions. One patient without a heart defect or microcephaly but with mild mental retardation and characteristic behavior had a smaller deletion within this commonly deleted region. Two patients without a heart defect had a more proximal interstitial deletion that did not overlap with the commonly deleted region. Taken together, these data allowed us to define the critical deletion regions for the major features of a del8p.

Prenatal diagnosis of an 8p23.1 deletion in a fetus with a diaphragmatic hernia and review of the literature

The prenatal diagnosis of an 8p23.1 deletion is reported. The diagnosis was ascertained at 22 weeks of gestation because of the discovery of a diaphragmatic hernia at ultrasound. Following cytogenetic studies and counselling, the pregnancy was terminated. An autopsy confirmed the presence of a diaphragmatic hernia and revealed also the existence of an atrio-ventricular canal (AVC) and an atrial septal defect (ASD). The clinical features of this antenatally diagnosed case are compared with those observed in 16 previously reported cases with an identical deletion of the short arm of chromosome 8. This suggests that a deletion 8p23.1 should be considered whenever a diaphragmatic hernia and/or an AVC is detected on ultrasound.