Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Microdeletion”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 343 records · Page 19Linked to original sources
PubMed1988

Microdeletions in patients with X-linked muscular dystrophy: molecular-clinical correlations.

The DNA from 68 patients with X-linked (Duchenne and Becker) muscular dystrophy belonging to 49 unrelated families was analyzed for microdeletions using 13 closely linked or gene-specific DNA-markers. Fourteen patients from eight families showed a deletion involving a least one of the markers used, giving a deletion frequency of 16%. The proportion of families with deletions was 36% in the Becker and 8% in the Duchenne form of the disease. With one exception, the extent of the deletion was different in different families. All living, affected males from the same family carried the same deletion. The extent or the localization of the deletion did not correlate with clinical features such as severity of disease or mental retardation.

Chromosome Deletion↗
PubMed2005

Evidence by expression analysis of candidate genes for congenital heart defects in the NF1 microdeletion interval.

It was recently reported that congenital heart disease is significantly more frequent in patients with NF1 microdeletion syndrome than in those with classical NF1. The outcome of congenital heart disease in this subset of patients is likely caused by the haploinsufficiency of gene/s in the deletion interval. Following in silico analysis of the deleted region, we found two genes known to be expressed in adult heart, the Joined to JAZF1 (SUZ12) and the Centaurin-alpha 2 (CENTA2) genes, and seven other genes with poorly defined patterns of expression and function. With the aim of defining their expression profiles in human fetal tissues (15th-21st weeks of gestation), expression analysis by RT-PCR and Northern blotting was performed. C17orf40, SUZ12 and CENTA2 were found to be mainly expressed in fetal heart, and following RT-PCR on mouse embryos and embryonic heart and brain at different stages of development, we found that the orthologous genes C17orf40, Suz12 and Centa2 are also expressed in early stages of development, before and during the formation of the four heart chambers. The presence of binding sites for Nkx2-5, a transcription factor expressed early in heart development, in all three mouse orthologous genes was predicted by bioinformatics, thus reinforcing the hypothesis that these genes might be involved in heart development and may be plausible candidates for congenital heart disease.

Animals↗
PubMed1996

Chromosome 22q11 microdeletions in tetralogy of Fallot.

Chromosome 22q11 fluorescence in situ hybridisation (FISH) studies were performed on 33 consecutive individuals attending a paediatric cardiology clinic with tetralogy of Fallot. Seven children had 22q11 microdeletions but only four had other clinical features associated with the newly recognised chromosome 22 deletion syndrome (CATCH 22). Chromosome 22q11 FISH studies should therefore be performed on all patients with tetralogy of Fallot.

Child↗
PubMed2002

Familial neurofibromatosis microdeletion syndrome complicated by rhabdomyosarcoma.

Neurofibromatosis type 1 with dysmorphism and developmental delay is reported in a mother and two children. The son required treatment for a prostatic rhabdomyosarcoma. His sister has an optic pathway glioma. Fluorescence in situ hybridisation confirmed a submicroscopic deletion at 17q11.2. New evidence suggests an increased malignancy frequency in microdeletion cases.

Adult↗
PubMed2005

Fryns syndrome phenotype caused by chromosome microdeletions at 15q26.2 and 8p23.1.

BACKGROUND: Fryns syndrome (FS) is the commonest autosomal recessive syndrome in which congenital diaphragmatic hernia (CDH) is a cardinal feature. It has been estimated that 10% of patients with CDH have FS. The autosomal recessive inheritance in FS contrasts with the sporadic inheritance for the majority of patients with CDH and renders the correct diagnosis critical for accurate genetic counselling. The cause of FS is unknown. METHODS: We have used array comparative genomic hybridisation (array CGH) to screen patients who have CDH and additional phenotypic anomalies consistent with FS for cryptic chromosome aberrations. RESULTS: We present three probands who were previously diagnosed with FS who had submicroscopic chromosome deletions detected by array CGH after normal karyotyping with G-banded chromosome analysis. Two female infants were found to have microdeletions involving chromosome band 15q26.2 and one male had a deletion of chromosome band 8p23.1. CONCLUSIONS: We conclude that phenotypes similar to FS can be caused by submicroscopic chromosome deletions and that high resolution karyotyping, including array CGH if possible, should be performed prior to the diagnosis of FS to provide an accurate recurrence risk in patients with CDH and physical anomalies consistent with FS.

Abnormalities, Multiple↗
PubMed2007

Osteopoikilosis, short stature and mental retardation as key features of a new microdeletion syndrome on 12q14.

This report presents the detection of a heterozygous deletion at chromosome 12q14 in three unrelated patients with a similar phenotype consisting of mild mental retardation, failure to thrive in infancy, proportionate short stature and osteopoikilosis as the most characteristic features. In each case, this interstitial deletion was found using molecular karyotyping. The deletion occurred as a de novo event and varied between 3.44 and 6 megabases (Mb) in size with a 3.44 Mb common deleted region. The deleted interval was not flanked by low-copy repeats or segmental duplications. It contains 13 RefSeq genes, including LEMD3, which was previously shown to be the causal gene for osteopoikilosis. The observation of osteopoikilosis lesions should facilitate recognition of this new microdeletion syndrome among children with failure to thrive, short stature and learning disabilities.

Abnormalities, Multiple↗
PubMed1991

Molecular and cytogenetic analysis of a familial microdeletion of Xq.

Cytogenetic analysis of a male infant referred for poor neurological development and failure to thrive showed a microdeletion of the X chromosome, his karyotype being 46,Y,del(X)(pter----q21.1:: q21.2----qter). His mother and grandmother were also found to carry the deletion. DNA probes were used to define the deletion molecularly and it was shown to span intervals 2 to 6 of Cremers et al, a portion of Xq that contains the TCD gene and genes whose absence is associated with deafness and mental retardation. RFLP analysis together with X inactivation studies using the probe M27 beta verified the carrier status of the female relatives and showed non-random X inactivation in the heterozygous females.

Chromosome Banding↗
PubMed1992

Screening of microdeletions of chromosome 20 in patients with Alagille syndrome.

We report a cytogenetic and molecular study of a series of patients with Alagille syndrome. All 14 patients were studied with high resolution banding techniques and eight of them were also analysed with non-radioactive in situ hybridisation of the cosmid probe D20S6. Seven of these eight patients were also studied for allelic losses at the D20S6 locus. No microdeletion of chromosome 20 was found in this series.

Alagille Syndrome↗
PubMed1993

Microdeletions of chromosomal region 22q11 in patients with congenital conotruncal cardiac defects.

Congenital conotruncal cardiac defects occur with increased frequency in patients with DiGeorge syndrome (DGS). Previous studies have shown that the majority of patients with DGS or velocardiofacial syndrome (VCFS) have a microdeletion within chromosomal region 22q11. We hypothesised that patients with conotruncal defects who were not diagnosed with DGS or VCFS would also have 22q11 deletions. Seventeen non-syndromic patients with one of three types of conotruncal defects most commonly seen in DGS or VCFS were evaluated for a 22q11 deletion. DNA probes from within the DiGeorge critical region were used. Heterozygosity at a locus was assessed using restriction fragment length polymorphisms. Copy number was determined by dosage analysis using Southern blot analysis of fluorescence in situ hybridisation of metaphase spreads. Five of 17 patients were shown to have a 22q11 deletion when evaluated by dosage analysis. This study shows a genetic contribution to the development of some conotruncal cardiac malformations and alters knowledge regarding the risk of heritability of these defects in certain cases.

Abnormalities, Multiple↗
PubMed1997

Recurrence risk figures for isolated tetralogy of Fallot after screening for 22q11 microdeletion.

Isolated tetralogy of Fallot (TF) has a multifactorial mode of inheritance in most cases, and recurrence risk rates of 2.5-3% have been attributed to first degree relatives of an affected child. In a subgroup of patients with a strong family history, the transmission of a monogenic trait has been suspected. Microdeletion 22q11 (del(22q11)) can cause TF in the setting of DiGeorge and velocardiofacial syndromes, and has also been related to familial conotruncal cardiac defects. Empirical risk figures in families after exclusion of del(22q11) have never been calculated. We have investigated the overall occurrence of congenital heart defect (CHD) in relatives of 102 patients with isolated non-syndromic TF previously screened for del(22q11). Our results show that the frequency of CHD is 3% in sibs, 0.5% in parents, 0.3% in grandparents, 0.2% in uncles or aunts, and 0.6% in first cousins. The recurrence risk rate for sibs in our series is the same as that previously estimated, indicating that after exclusion of patients with del(22q11) genetic counselling to patients with isolated TF should not be modified. A high concordance rate among our affected sibs has been documented. Gene(s) different from those located on chromosome 22q11 must be involved in causing familial aggregation of non-syndromic TF in these cases.

Adolescent↗
PubMed1999

Microdeletions in FMR2 may be a significant cause of premature ovarian failure.

Genetic causes of premature ovarian failure (POF) include X chromosome deletions and fragile X (FRAXA) premutations. While screening a cohort of women with POF for FRAXA premutations, a more distal trinucleotide repeat, FRAXE, was also tested. We found an unexpected excess of FRAXE alleles with apparently fewer than 11 repeats in the POF group. However, sequence analysis of these alleles showed that the excess was caused by three females who carry cryptic deletions in FMR2, the gene associated with FRAXE. We propose that microdeletions within FMR2 may be a significant cause of premature ovarian failure, being found in 1.5% of women with the condition, and in only 0.04% of the general female population. The deletions may affect transcription of either FMR2 or an adjacent gene.

Adult↗
PubMed2000

A microdeletion in 19q13.2 associated with mental retardation, skeletal malformations, and Diamond-Blackfan anaemia suggests a novel contiguous gene syndrome.

Diamond-Blackfan anaemia (DBA) is a constitutional red blood cell hypoplasia which may be associated with a variety of developmental abnormalities. A gene for DBA was recently mapped to chromosome 19q13.2 and subsequently cloned. Analysis of 19q marker alleles in DNA of sporadic DBA cases showed de novo microdeletions in three patients also presenting with mental retardation. We have studied one of these patients and characterised the deletion by fluorescence in situ hybridisation (FISH) to extended DNA fibres. The deletion was shown to be continuous over a 3.2 Mb region and the fibre-FISH analysis showed both chromosomal breakpoints. In combination, the clinical and molecular findings suggest a contiguous gene syndrome with a gene locus for mental retardation and, probably, skeletal malformations included in the deletion.

Bone and Bones↗
PubMed2001

Detection of microdeletions in the short arm of the X chromosome by chromosome stretching.

The present study was focused on the resolution of "chromosome stretching". In order to determine if this method can be used for the detection of microdeletions, the p-arms of 13 normal X chromosomes were stretched as well as of those with three different deletions of known size within the DMD/BMD region in Xp21 (case A: 0.42-0.45 Mb, case B: 2.3-2.9 Mb and case C: 3.0-3.5 Mb). The process of band splitting was recorded on a video-tape and the resulting banding pattern analyzed. Stretching of the normal Xp-arms led to a splitting on a maximum band level of 1400 and showed in all cases an identical banding pattern with 13 Giemsa-dark subbands. All new Giemsa-dark and -light subbands were derived from the three initial Giemsa-dark bands at the 400 band level according to ISCN (1995): five subbands from Xp21, four subbands from Xp11.3 and Xp22.2, respectively. The origin of these subbands is partly in contrast to the high resolution ISCN (1995) ideograms: subband Xp11.22 does not originate from the Giemsa-light band Xp11.2, but from the Giemsa-dark band Xp11.3; Xp22.12 originates from Xp21; Xp22.32 from Xp22.2. Stretching of the chromosomes containing deletions showed in cases A and B no differences in banding patterns and splitting order compared to normal X chromosomes. Only in patient C was a significant difference with the normal pattern visible due to the absence of one dark subband. In this case only four Giemsa-dark subbands derived from band Xp21. Thus, at least in the DMD/BMD region, the minimal size of a deletion detected by chromosome-stretching-generated high-resolution ideograms is about 3.0-3.5 Mb.

Azure Stains↗
PubMed2002

Identification and characterisation of the gene TWIST NEIGHBOR (TWISTNB) located in the microdeletion syndrome 7p21 region.

We have characterised a 2.4-Mb genomic sequence of a smallest region of overlap (SRO) deleted in the human microdeletion syndrome 7p21 by in silico analysis. Patients harbouring this minimal deletion present in addition to the clinical features of Saethre-Chotzen syndrome (MIM 101400) a distinct learning disability. This genomic region shows a very low gene content. Besides the transcription factor gene TWIST, the Histone Deacetylase 9 (HDAC9), Sorting Nexin 13 (SNX13) and an evolutionarily conserved bHLH transcription factor gene Nephew of Atonal 3 (HNATO3) have been detected previously. Here we describe the localisation and characterisation of the TWIST NEIGHBOR (TWISTNB) gene. Comparison of the predicted proteins of human TWISTNB and mouse Twistnb shows a high degree of conservation. Northern blot analysis of human fetal and adult tissues shows ubiquitous expression in all tissues tested.

Acrocephalosyndactylia↗
PubMed2006

A 17q21.31 microdeletion encompassing the MAPT gene in a mentally impaired patient.

About 15% of patients with a clinical phenotype of Angelman syndrome (AS) have an unknown etiology. We report a patient with features reminiscent of AS, including a pattern of characteristic facial anomalies as well as speech impairment, developmental delay and frequent laughter. In addition, the patient had features not commonly associated with AS such as heart malformations and scoliosis. She was negative in SNURF-SNRPN exon 1 methylation studies and the G-banded karyotype was normal. Array-based comparative genomic hybridization disclosed a deletion of maximally 1 Mb at 17q21.31. The deleted region contains the MAPT gene, implicated in late onset neurodegenerative disorders, and the STH and NP_056258.1 genes. Another gene, such as CRHR1, might also be included based on maximum possible size of the deletion. We suggest that microdeletions within the 17q21.31 segment should be considered as a possible cause of phenotypes resembling AS, particularly when easily controlled seizures and/or cardiac abnormalities are also present.

Abnormalities, Multiple↗
PubMed1996

Microdeletions in interval 6 of the Y chromosome detected by STS-PCR in 6 of 33 patients with idiopathic oligo- or azoospermia.

It has been proposed that interval 6 of the human Y chromosome contains the gene or genes that control spermatogenesis (AZF, azoospermia factor). We have studied this region in 33 patients with oligo- or azoospermia, using PCR amplification of the YRRM1 (RBM1) gene and of 13 sequence-tagged sites (STSs), all mapping within interval 6. Six of the 33 patients showed no amplification of specific STSs, whereas there was no failure of amplification in normal male controls. We deduce that these six patients had microdeletions in interval 6 of the Y chromosome that correlated with the oligo- or azoospermia of these individuals. On biopsy of the testis, two of these patients showed a low number of germ cells, and four showed arrest with spermatides. We conclude that PCR amplification of Y-specific regions is a powerful and very sensitive tool for screening infertile men.

Adult↗
PubMed2004

A microdeletion in the ligand binding domain of human steroidogenic factor 1 causes XY sex reversal without adrenal insufficiency.

Steroidogenic factor 1 (SF-1) is an orphan nuclear receptor that plays key roles in endocrine development and function. Knockout mice lacking SF-1 have adrenal and gonadal agenesis, impaired gonadotropin expression, and structural abnormalities of the ventromedial hypothalamic nucleus. Previous studies have identified three human subjects with mutations in SF-1 causing adrenocortical insufficiency with varying degrees of gonadal dysfunction. We now describe a novel 8-bp microdeletion of SF-1, isolated from a 46, XY patient who presented with gonadal agenesis but normal adrenal function, which causes premature termination upstream of sequences encoding the activation function 2 domain. In cell transfection experiments, the mutated protein possessed no intrinsic transcriptional activity but rather inhibited the function of the wild-type protein in most cell types. To our knowledge, this is the first example of an apparent dominant-negative effect of a SF-1 mutation in humans. These findings, which define a SF-1 mutation that apparently differentially affects its transcriptional activity in vivo in the adrenal cortex and the gonads, may be relevant to the cohort of patients who present with 46, XY sex reversal but normal adrenal function.

Adrenal Glands↗