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At least 811 records · Page 45Linked to original sources
PubMed1994

Two patients with overlapping de novo duplications of the long arm of chromosome 9, including one case with Di George sequence.

Duplications of chromosome 9q are rare. We describe the cytogenetic and phenotypic findings in 2 patients, one with a large duplication covering most of 9q(q12-q33.2) and one with a smaller duplication (q21.12-q22.1) who had Di George sequence (DGS). The chromosome 9 origin of the extra material in the second case was confirmed by fluorescence in situ hybridization (FISH) analysis with a whole chromosome 9 paint. Microdeletions of chromosome 22 are common in DGS and have been reported in CHARGE association. This is the first report of an association of a chromosome 9 abnormality with DGS in the absence of a chromosome 22 abnormality and the seventh report of a patient with a duplication of a large portion of 9q (q11-q13 to q32-q33).

Abnormalities, Multiple↗
PubMed1994

Molecular diagnosis of Prader-Willi syndrome: parent-of-origin dependent methylation sites and non-isotopic detection of (CA)n dinucleotide repeat polymorphisms.

We describe our experience in the molecular diagnosis of 22 patients suspected of Prader-Willi syndrome (PWS) using a DNA probe PW71 (D15S63) which detects a parent-of-origin specific methylated site in the PWS critical region. The cause of the syndrome was determined as deletion or uniparental disomy according to the segregation of (CA)n dinucleotide repeat polymorphisms of the PWS/AS region and more distal markers of chromosome 15. In 10 patients the clinical diagnosis was confirmed by this approach, 6 with paternal deletion and 4 with maternal disomy. In one patient, the aberrant methylation pattern that was detected by PW71 could not be confirmed by the segregation of (CA)n, probably due to paternal microdeletion in the PWS critical region which did not include the loci D15S97, D15S113, GABRB3, and GABRA5. This case demonstrates the advantage of the DNA probe PW71 in the diagnosis of PWS.

Adolescent↗
PubMed1994

Hypoparathyroidism as the major manifestation in two patients with 22q11 deletions.

We report on two adolescents with 22q11 deletion. Their main clinical manifestation was chronic symptomatic hypocalcemia secondary to hypoparathyroidism, together with seizures and cerebral calcifications. Neither congenital cardiac abnormality nor T cell deficiency were detected. The phenotypic manifestations of the observed patients were consistent with velo-cardio-facial syndrome (VCFS). A microdeletion of chromosome region 22q11 has been demonstrated in approximately 90% of DiGeorge syndrome (DGS) patients and in 75% of VCFS patients; the association of the deletion with a wide spectrum of clinical findings suggests the existence of a contiguous gene syndrome. The presence of certain traits of DGS/VCFS should lead to investigations of the parathyroid function and molecular analysis of the 22q11 region hybridization studies.

Adolescent↗
PubMed1994

Brain anomalies in velo-cardio-facial syndrome.

Magnetic resonance imaging of the brain in 11 consecutively referred patients with velo-cardiofacial syndrome (VCF) showed anomalies in nine cases including small vermis, cysts adjacent to the frontal horns, and small posterior fossa. Focal signal hyperintensities in the white matter on long TR images were also noted. The nine patients showed a variety of behavioral abnormalities including mild developmental delay, learning disabilities, and characteristic personality traits typical of this common multiple anomaly syndrome which has been related to a microdeletion at 22q11. Analysis of the behavioral findings showed no specific pattern related to the brain anomalies, and the patients with VCF who did not have detectable brain lesions also had behavioral abnormalities consistent with VCF. The significance of the lesions is not yet known, but the high prevalence of anomalies in this sample suggests that structural brain abnormalities are probably common in VCF.

Abnormalities, Multiple↗
PubMed1995

Classical Noonan syndrome is not associated with deletions of 22q11.

Deletions of 22q11 cause DiGeorge sequence (DGS), velo-cardio-facial syndrome (VCFS), conotruncal anomaly face syndrome, and some isolated conotruncal heart anomalies. Demonstration of a 22q11 deletion in a patient with manifestations of DGS and Noonan syndrome (NS) has raised the question of whether NS is another of the chromosome 22 microdeletion syndromes. This prompted us to evaluate a cohort of patients with NS for evidence of 22q11 deletions. Five of 6 NS propositi studied in our laboratory with marker N25 (D22S75) did not have a 22q11 deletion. A 2-month-old infant with several findings suggestive of NS did have a 22q11 deletion, suggesting that a small number of 22q11 deletion propositi may present with a NS-like picture. However, most cases of NS must have another cause.

Adolescent↗
PubMed1995

Angelman syndrome: validation of molecular cytogenetic analysis of chromosome 15q11-q13 for deletion detection.

In a series of 18 individuals comprising parents of Angelman syndrome (AS) patients and AS patients with large deletions, microdeletions, and no deletions, we utilized fluorescence in situ hybridization (FISH) with genomic phage clones for loci D15S63 and GABRB3 for deletion detection of chromosome 15q11-q13. Utilization of probes at these loci allows detection of common large deletions and permits discrimination of less common small deletions. In all individuals the molecular cytogenetic data were concordant with the DNA deletion analyses. FISH provides an accurate method of deletion detection for chromosome 15q11-q13.

Angelman Syndrome↗
PubMed1995

FISH analysis in Prader-Willi and Angelman syndrome patients.

We report on a combined high resolution cytogenetic and fluorescent in situ hybridization study (FISH) on 15 Prader-Willi syndrome (PWS) and 14 Angelman syndrome (AS) patients. High resolution banding showed a microdeletion in the 15q11-q13 region in 7 out of 15 PWS patients, and FISH analysis of the D15S11 and SNRPN cosmids demonstrated absence of the critical region in three additional cases. Likewise 8 out of 14 AS patients were found to be deleted with FISH, using the GABRB3 specific cosmid, whereas only 4 of them had a cytogenetically detectable deletion.

Angelman Syndrome↗
PubMed1995

Autosomal dominant "Opitz" GBBB syndrome due to a 22q11.2 deletion.

We report on a family with autosomal dominant paternally inherited "Opitz" GBBB syndrome and an additional case with findings which have been reported in that syndrome. In each case the propositus presented with a vascular ring. Since a vascular ring may be a sign of a 22q11.2 deletion [Zacki et al., 1995], FISH (fluorescence in situ hybridization) studies were performed. These studies demonstrated a 22q11.2 deletion in the 3 affected individuals. Review of Opitz GBBB syndrome and the 22q11.2 microdeletion syndrome demonstrates significant overlap of manifestations including both facial characteristics and structural anomalies. Based on the phenotypic overlap and the presence of a 22q11.2 deletion in our patients with Opitz GBBB syndrome and the presence of a deletion in a patient with lung hypoplasia, absent pulmonary artery, and long segment tracheomalacia, we propose that, in some cases, the Opitz GBBB syndrome may be due to a 22q11.2 deletion. This enlarges the list of "syndromes" associated with the 22q11.2 deletion, which presently includes most patients with DiGeorge, velocardiofacial, and conotruncal anomaly face syndrome.

Abnormalities, Multiple↗
PubMed2001

SMN2-deletion in childhood-onset spinal muscular atrophy.

The human genome has two homologous survival motor neuron genes, SMN1 and SMN2. Although deletions of SMN1 are frequently reported in childhood-onset spinal muscular atrophy (SMA), SMN2 have been found to be intact in patients with the disorder. We report on a 5-year-old boy with childhood-onset SMA who has a homozygous deletion of SMN2. He had wasting, weakness, and hyporeflexia, predominantly in the distal muscles. The muscles involved showed chronic neurogenic changes on electromyogram. There was no sensory involvement. A nerve conduction study showed near normal conduction velocity with reduction in the amplitude of the compound muscle action potential. Analysis of polymerase chain reaction-restriction fragment length polymorphism as well as single-strand conformation polymorphism on exons 7 and 8 of the SMN genes revealed the SMN2-deletion. Base sequencing and densitometric analysis of the critical region (exon 7) did not show any microdeletion or duplication of SMN1, but confirmed the deletion of SMN2. We conclude that a deletion of SMN2 may also result in the SMA phenotype.

Child↗
PubMed2001

An 8-cM interstitial deletion on 4q21-q22 in DNA from an infant with hepatoblastoma overlaps with a commonly deleted region in adult liver cancers.

We performed molecular analysis of a germline interstitial deletion of chromosome 4 [del(4)(q21.22q23)], which had been observed in a male infant manifesting early-onset hepatoblastoma (HBL). The chromosomal anomaly in this child was associated with a unique congenital syndrome including HBL, atrial septal defect, ventricular septal defect, patent ductus arteriosus, mental retardation, and seizures. However, the patient did not exhibit a megalencephaly typical of 4q21-22 deletions. His HBL was associated with an increasing serum alpha-fetoprotein level and rapid growth. To define the chromosomal deletion at the molecular level in this child, we analyzed his lymphoblasts with fluorescence in situ hybridization, using as probes a panel of BAC/PAC genomic clones containing STS markers covering the 4q12-27 region. The analysis revealed that the affected chromosome had an 8-cM deletion within 4q21-q22, flanked by markers D4S2964 and D4S2966. This microdeletion overlaps with the commonly deleted region at 4q21-q22 that was recently defined in adult hepatocellular carcinomas.

Adult↗
PubMed2003

Absence of 12q21.2q22 deletions and subtelomeric rearrangements in cardiofaciocutaneous (CFC) syndrome patients.

Recent publications described two patients with a CFC-like phenotype and the same deletion of chromosome region 12q21.2q22 [Rauen et al., 2000, 2002]. The patients did not have the classical CFC phenotype and presented other signs not usually seen in CFC patients: the first patient had hydrocephalus, and the second, a history of olygohydramnios, normal stature, pyloric stenosis, cutaneous syndactyly of toes and bilateral transverse palmar creases. In order to verify if classic CFC patients with normal chromosomes in conventional preparations have microdeletions within the 12q21.2q22 chromosome region, we performed FISH analysis using 12 BAC probes to screen this area. The average interval between the probes was of approximately 1 Mb. No deletions were found in any of the 17 classical CFC patients we examined. We conclude that the region 12q21.2q22 is not a candidate region for CFC syndrome and that the patients described by Rauen et al. [2000, 2002] probably have a different condition, i.e., an aneuploidy syndrome, with some phenotypic resemblance to the CFC syndrome. To further evaluate the possibility of other chromosome imbalances, we performed a subtelomeric analysis, by FISH technique, of all chromosomes, and did not find any subtelomeric rearrangements.

Adolescent↗
PubMed2003

Velocardiofacial syndrome in an unexplained XX male.

We report the unusual finding of velocardiofacial syndrome (VCF) in an unexplained 46,XX male. A microdeletion of 22q11.2 was confirmed by fluorescence in situ hybridization (FISH) analysis. Routine G-banded chromosome analysis revealed an XX sex chromosome constitution. FISH was performed using the SRY probe and failed to detect hybridization. The sex chromosome status of the patient was further investigated by PCR testing to screen for the presence of 24 distinct loci spanning the Y chromosome. PCR screening failed to detect any apparent Y chromosome material.

Abnormalities, Multiple↗
PubMed2003

Sequence-based, in situ detection of chromosomal abnormalities at high resolution.

We developed single copy probes from the draft genome sequence for fluorescence in situ hybridization (scFISH) which precisely delineate chromosome abnormalities at a resolution equivalent to genomic Southern analysis. This study illustrates how scFISH probes detect cryptic and subtle abnormalities and localize the sites of chromosome rearrangements. scFISH probes are substantially shorter than conventional recombinant DNA-derived probes, and C(o)t1 DNA is not required to suppress repetitive sequence hybridization. In this study, 74 single copy sequence probes (>1,500 bp) have been developed from >/=100 kb genomic intervals associated with either constitutional or acquired disorders. Applications of these probes include detection of congenital microdeletion syndromes on chromosomes 1, 4, 7, 15, 17, 22 and submicroscopic deletions involving the imprinting center on chromosome 15q11.2q13. We demonstrate how hybridization with multiple combinations of probes derived from the Smith-Magenis syndrome interval on chromosome 17 identified a patient with an atypical, proximal deletion breakpoint. A similar multi-probe hybridization strategy has also been used to delineate the translocation breakpoint region on chromosome 9 in chronic myelogenous leukemia. Probes have also been designed to hybridize to multiple cis paralogs, both enhancing the chromosomal target size and detecting chromosome rearrangements, for example, by splitting and separating a family of related sequences flanking an inversion breakpoint on chromosome 16 in acute myelogenous leukemia. These novel strategies for rapid and precise characterization of cytogenetic abnormalities are feasible because of the sequence-defined properties and dense euchromatic organization of single copy probes.

Adult↗
PubMed2003

De novo paracentric inversion (X)(q26q28) with features mimicking Prader-Willi syndrome.

Different genetic and non-genetic disorders, including several chromosomal abnormalities, may mimic Prader-Willi syndrome (PWS). We report on an 11-year-old girl with features reminiscent of PWS due to an unreported de novo paracentric inversion Xq26q28. Microdeletion 15q11-q13 and maternal uniparental disomy 15 were ruled out. The importance of chromosomal studies in addition to molecular analysis on patients with features suggestive of PWS is stressed.

Child↗
PubMed2003

Isolated postaxial polydactyly type B with mosaicism of a submicroscopic unbalanced translocation leading to an extended phenotype in offspring.

Postaxial polydactyly (PAP) is characterized by the presence of one or more extra ulnar or fibular digits or parts of it. PAP type B presents frequently as a skin tag on the hand(s). It is usually an isolated malformation, but in 6.6% it is associated with other congenital abnormalities, mostly well recognizable syndromes. We present a male with PAP-B only and his daughter with an extended phenotype including mental retardation and minor dysmorphisms. Both share a cytogenetically balanced t(4;7)(p15.2;q35), present in mosaicism in the father. We found microdeletions associated with the breakpoints. The chromosomal regions described here have not been previously associated with the PAP-B phenotype. We present the first case of an individual with isolated PAP-B and a submicroscopic chromosome abnormality.

Abnormalities, Multiple↗
PubMed2003

A novel 5q35.3 subtelomeric deletion syndrome.

We observed a novel 3.5 Mb 5q subtelomeric deletion in a 3-year-old girl with developmental delay, hypotonia and multiple minor anomalies. Comparison of her phenotype with the few published patients with terminal 5q35 deletions revealed several overlapping features, but also showed remarkable differences such as shortness of stature versus macrosomia. After the report of 5q35.3 microdeletions in Sotos syndrome we integrated the published BACs into the public draft sequence and exactly mapped the deletion size in our patient by FISH analysis with 15 BAC probes. We demonstrated that the deletion in our patient is immediately adjacent to the reported Sotos syndrome deletion site. Subtracting the symptoms of Sotos syndrome from the published patients with larger 5q35.3 deletions allowed us to delineate a distinct phenotype of prenatal lymphedema with increased nuchal translucency, pronounced muscular hypotonia and delay of reaching motor milestones, but speech development within normal limits, wide fontanels, failure to thrive with postnatal short stature, and multiple minor anomalies such as mildly bell-shaped chest, minor congenital heart disease, and a distinct facial gestalt, associated with the novel 3.5 Mb cryptic deletion. We further showed in our patient that the deletion of the LCT(4) synthase gene results in a reduction of cysteinyl leukotriene synthesis to about 65% compared to normal values. The prenatal nuchal lymphedema associated with this deletion syndrome my be related to the deletion of the FLT4 gene causing autosomal dominant primary lymphedema and contributes to the differential diagnosis of increased fetal nuchal translucency.

Child, Preschool↗
PubMed2003

Screening of patients with craniosynostosis: molecular strategy.

Craniosynostosis is the premature fusion of calvarial bones leading to an abnormal head shape. The craniosynostosis syndromes are clinically heterogeneous with overlapping features, which make an accurate diagnosis difficult at times. Although the clarification of a genetic lesion does not have a direct impact on patient management in many cases, there is a significant benefit in providing accurate prenatal diagnosis. Genetic counsellors are also able to offer better risk estimates of recurrences to non-manifesting carriers and their extended family members and for affected patients of reproductive age. Advances in gene discovery have shown that craniosynostosis syndromes delineated on clinical bases, with the possible exception of Apert syndrome, are genetically heterogeneous, and mutations have been found in fibroblast growth factor receptors (FGFR) 1, 2, 3 and TWIST. We surveyed 99 craniosynostosis patients at the molecular level and found mutations in 50 of them. Six novel point mutations were identified: three in FGFR2 and three in TWIST. Two Saethre-Chotzen patients with TWIST microdeletions at 7p21 were also found. The other mutations identified have been previously reported. In studying these 99 patients, we developed a diagnostic strategy for craniosynostosis testing, where sequential analysis of recurrent mutations was followed by selective sequencing. This algorithm makes testing of craniosynostosis disorders more efficient and cost-effective.

Craniosynostoses↗
PubMed2004

Lissencephaly with der(17)t(17;20)(p13.3;p12.2)mat.

The isolated lissencephaly sequence may be caused by point mutations of the LIS1 gene or by FISH-detectable microdeletions of the 17p13.3 region, which carries the LIS1 gene. These have various patterns of phenotypic presentations, including the Miller-Dieker syndrome (MDS). Approximately 20% of these deletions are associated with a derivative chromosome 17 inherited from a parent who has a balanced reciprocal translocation involving chromosome 17 and another chromosome. We report a case of lissencephaly associated with a maternally inherited unbalanced translocation involving chromosome arms 17p and 20p. This results in partial monosomy of 17p13.3-->pter and partial trisomy of 20p12.2-->pter. To our knowledge, this is the first report of a reciprocal translocation between 17p and 20p. Our patient has a combination of findings of the MDS and trisomy 20p, along with several unique anomalies not described in either of those two conditions. This report may contribute to the delineation of a phenotype resulting from partial monosomy 17p and partial trisomy of 20p.

Abnormalities, Multiple↗