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PubMedDate not supplied

A case with some clinical findings overlapping to Rubinstein-Taybi, Rubinstein-Taybi-like syndrome or multiple pterygium syndrome: coincidental findings or a new entity?

We report a case with broad, deviated thumb and big, duplicated, deviated toes resembling Rubinstein-Taybi syndrome. But the patient did not have severe mental retardation as in Rubinstein-Taybi syndrome and had no microdeletions on chromosome 16 by FISH-based assay. This patient had mild webbing as seen in multiple pterygium syndrome, but broad-deviated thumb has not been reported in this syndrome. We discuss whether these are coincidental or overlapping findings or whether this is a possible new clinical entity.

Child↗
PubMed2000

[Spectrum and methods of detection of mutations in a phenylalanine hydroxylase gene from patients with phenylketonuria from the Novosibirsk region].

Phenylketonuria (PKU) is a widespread autosome recessive hereditary disease caused by a deficiency of the liver enzyme phenylalanine hydroxylase, which results in the distortion of phenylalanine metabolism and accumulation of toxic metabolites. The knowledge of molecular bases of PKU is of a high social importance as it enables phenotypic correction of the disease in the case of its early diagnostics. This disease is known to be associated with mutations in the phenylalanine hydroxylase gene, the distribution and mutation spectrum having pronounced ethnic and regional features. We studied the spectrum of mutations in the phenylalanine hydroxylase gene in a group of patients with PKU from the Novosibirsk region to reveal 10 missense point mutations, 1 mutation in the splice donor site, and 1 microdeletion. For these mutations, most widely distributed in the region, we used straightforward detection methods based on the restriction fragment length polymorphism (RFLP), artificial constructed restriction sites (ACRS) PCR, and denaturing gradient gel electrophoresis (DGGE).

Humans↗
PubMed2001

[Idiopathic male infertility and androgen receptors].

In France, 12 to 15% of couples experience procreation difficulties. A disorder of spermatogenesis (oligospermia, azoospermia) is responsible in 1/3 of cases. These forms of infertility, labelled idiopathic, probably have a genetic component, like microdeletions of the Y chromosome. The normal rate of circulating androgens suggests the implication, in some cases, of an abnormality from the receptor to the androgens (RA) of these male infertilities, whose number remains to be defined. Point mutations on exons of the gene encoding the AR cannot account for all cases of infertility due to idiopathic disorders of spermatogenesis. Expansion of the number of CAG triplets of exon 1 of the AR gene, already demonstrated in a fatal degenerative neuropathy (Kennedy's disease, in which more than 50% of patients are infertile), has been detected in these cases of idiopathic infertility and would be responsible for AR dysfunction. The number of these triplets is also decreased in patients with androgen-dependent prostate cancer. The polymorphism of repetition of CAG triplets would therefore be responsible for fine adjustment of the AR between excessive and insufficient function. ICSI. (Intra-Cytoplasmic Sperm Injection) is currently proposed in these cases of infertility, but the consequences of transmission of these abnormalities to the offspring are unknown.

Humans↗
PubMed2002

[Medical genetics in reproductive medicine].

Reproductive genetics (RG) is another new field of medical genetics, integrated with reproductive medicine, assisted reproduction and developmental genetic. RG is closely linked to the perioconceptional prevention, perinatology, ultrasound and biochemical screening in the end of the first and beginning of the second trimesters. RG is based on the system of specialized genetic counseling, clinical cytogenetics, molecular cytogenetics and molecular genetics to provide prefertilization, preimplantation and classical prenatal diagnosis in the Ist to IIIrd trimesters. Thus, RG is part of the fetal medicine and therapy. The six years experience with RG is summarized. A system of the specialized health care, organized, if possible in one integrated center of RG and reproductive medicine (RM) is presented. Reproductive medicine provides all necessary clinical gynecological and andrological surveillance, with assisted reproduction and further obstetrical ultrasound examinations, including nuchal translucency measurements and 2D, 3D ultrasound, echocardiography examinations, if indicated, as well as the invasive method of prenatal diagnosis and perinatology care. Specialized genetic counseling and cytogenetic analysis, if indicated, should be offered to all partners with reproductive disorders as well as to oocyte donors. Chromosome anomalies are disclosed in 6% of men with abnormal sperm analysis as well as in women with severe reproductive disorders. In males with severe oligo, azoospermia, the sperm aneuploidy analysis by molecular cytogenetic methods is recommended. Advised is also the molecular genetic detection of Y chromosome microdeletions, which is detected in 9% of our azoospermic men with deletions in AZFb region. CFTR gene mutations and intron 8 and 10 polymorphism examination is provided not only in men with obstructive azoospermia (CBAVD), but also if severe oligospermy with less than 1 x 10(6) sperm/ml is detected. Molecular genetic analysis of thrombophilic mutations of factor II., V. (Leiden) and MTHFR gene in unexplained recurrent abortions and in cases with unsuccessful IVF is part of the diagnostic strategy. The population frequencies of carriers of mutations of factor II. (2.3%), factor V.-Leiden (5.7%) and MTHFR gene (38%) were determined. The laser biopsy of the first polar body and of blastomeres was introduced for FISH analysis of chromosome aneuploidies. Quantitative fluorescent PCR (QFPCR) detection is used for testing of the most frequent delta F508 CFTR gene mutation and the most frequent aneuploidies of chromosome 13, 18, 21, X and Y. QFPCR was successfully tested for male fetal sex examination from partially purified fetal cells in the maternal blood. The first trimester ultrasound and biochemical screening is recommended to all successful pregnancies after different IVF methods. If borderline levels of first trimester biochemical screening of PAPP-A protein and beta hCG are detected without pathological ultrasound findings, classical triple test of biochemical screening in 16th week of gestation is recommended. If pathological results of ultrasound and biochemical screening are disclosed, invasive prenatal genetic diagnosis is indicated as well as in pregnancies after ICSL, if there is not any obstetrical contraindication.

Chromosome Disorders↗
PubMed1998

[Syndromes 3. Velo-cardio-facial (VCF/Shprintzen) syndrome].

The clinical symptomatology of the velo-cardio-facial (VCF/Shprintzen) syndrome is briefly described. In VCF syndrome a microdeletion of chromosome 22q11.2 can be found, as well as in a number of other clinical entities, leading to the conclusion that it is probably better to speak of the 22q11.2 clinical spectrum.

Abnormalities, Multiple↗
PubMed2001

[Clinical features of a senior patient with Williams syndrome].

We experienced a case of 62-year-old woman who was admitted for the evaluation of her trembling hands. She was diagnosed as Williams syndrome (WS) by fluorescent in situ hybridization (FISH) analysis. She was short in stature, had a characteristic face and moderate mental retardation, whereas she was talkative and gregarious. She also presented impaired visuospatial cognition, cerebellar ataxia and tremor like involuntary movement of the hands. No remarkable abnormality is noted in MRI of the brain. MRA study of the brain revealed the arteriosclerotic vascular change, such as elongation of basilar artery and dilatation of bilateral carotid arteries. Heterozygous microdeletion of chromosome 7q11.23 of this patient is typical for WS, the delction including elastin (ELN) and LIMK 1 gene. Although she was complicated by diabetes mellitus and hyperlipidemia, she had no cardiovascular abnormalities like supravalvular aortic stenosis (SVAS), and survived to her age in good condition. The tremor-like involuntary movement disappeared after her discharge and its mechanism remains to be elucidated.

Brain↗
PubMed2002

The velocardiofacial syndrome: a review.

The Velocardiofacial syndrome is characterised by a complex clinical behavioural phenotype, resulting from the imbalance of normal dosage genes located on 22q11. Low copy repeat gene clusters are known to flank the microdeleted region and predispose to unequal crossing over events resulting in the interstitial 22q11 deletion. Involvement of multiple disease genes is strongly suspected and traditional positional cloning techniques as well as mouse models are used to identify the involved genes.

Abnormalities, Multiple↗
PubMedDate not supplied

[Spectrum and frequencies of RB1 gene structural defects in retinoblastoma].

The spectrum and frequencies of RB1 structural defects were studied in tumors and peripheral blood lymphocytes of patients with various forms of retinoblastoma. Single strand conformation polymorphism (SSCP) and heteroduplex (HA) analyses, along with direct sequencing, revealed 47 mutations, including 24 new ones. Of these, 42.5% were nonsense mutations, 15% were missense mutations, 15% affected splicing sites, and 27.5% were frameshifts resulting from microdeletions or microinsertions. Six polymorphisms were found, including three new ones located in the coding region. Microsatellite analysis with markers Rbint2, Rbint20, D13S262, and D13S284 revealed a loss of heterozygosity for at least one marker in 71% tumors.

Alternative Splicing↗
PubMed2002

Retinal histopathology of an XLRP carrier with a mutation in the RPGR exon ORF15.

X-linked retinitis pigmentosa comprises the severe forms of RP, with early onset of night blindness, rapid constriction of visual fields and eventual loss of central acuity. Of the five distinct XLRP loci identified on the X chromosome, mutations have been found only in the RP2 and RPGR genes. Of these, mutations in RPGR are more common, particularly in a mutational hot spot that was identified in the newly discovered exon ORF15. We report on an extended family with a microdeletion in RPGR exon ORF15 and the retinal histopathology of a female carrier of this mutation. We found a 1bp deletion at position 632 in exon ORF15 in affected members of family XLRP-319. This mutation alters the reading frame of the predicted RPGR protein, resulting in a premature stop codon. The mutation segregated with disease in three generations of the family and was associated with severe early onset retinal disease in affected men. The retina from a 75 year old carrier female donor had slight photoreceptor loss in the less diseased areas. More severe atrophy with retinal pigment epithelium (RPE) migration was present in areas of the mid- and far periphery. By immunocytochemistry, loss of rhodopsin labelling in rods was found in the areas of focal atrophy and loss of uniform cone spacing was apparent even in well preserved regions. Small multifocal areas of outer retinal degeneration were present in the better preserved regions of the eye. In these foci, rod and cone loss did not coincide. The dissociation of rod and cone degeneration in areas of focal disease is consistent with random X-inactivation early in embryonic development and the occurrence of distinct patterns of radial (rod) and tangential (cone) dispersion during clonal expansion early in photoreceptor differentiation.

Adult↗
PubMedDate not supplied

[Molecular genetics of radiation-induced chromosome breaks in a gene area in Drosophila: "position" effect of gene mutation?].

On the sample of 43 gamma-ray and neutron-induced inversion or translocation exchanges with the vestigial (vg) phenotype, the molecular cytogenetic analysis of distribution of exchange breakpoints on the molecular map of Drosophila vg region (subsection 49D3-4 on the polytene chromosome 2R) was performed using hybridisation in situ technique. Simultaneously, PCR-assay of DNA alterations in all exons and introns (except for intron 4) of the vg gene for 18 mutants with exchange breakpoints outside of the gene was carried out. The results obtained by these molecular genetic techniques have shown that 1) radiation-induced breaks under chromosome exchanges with the vg phenotype were regularly located inside of the vg gene (19 cases out of 43 studied ones or 44.2%) passing through the large introns; 2) breakpoints were frequently flanked by deletions of the gene as whole (3 exchanges) or of its major part (3 exchanges); 3) many of the breaks (18/43 or 41.8%) are situated outside (distal or proximal) of the gene although such mutants have got the vg phenotype; 4) 2/3 (12/18 or 66.7%) vg mutants with the breakpoint outside of gene show the intragenic DNA lesions (microdeletions, microinversions) occurring obviously independently and simultaneously with the neighbor chromosome breaks; 5) only each third vg mutant with break outside of the gene (6/18 or 33.3%) have the unchanged gene subregions under study and presents obviously the result of "position effect" which appear to manifest itself for a distance of 2-30 kb (more near and farther locations of the proximal and distal breakpoints, respectively, relative to the vg gene). Our findings showing regular induction of the multiple genetic lesions (chromosome breaks and mutations of the adjacent genes) on the both ends of chromosome exchange induced by single track produced by gamma-rays or neutrons were discussed as a scientific basis for the conceptually new approaches to the assessment of both genetic damage numbers in the cell genome with chromosome exchange (the multiple genetic lesions) and radiation genetic risk (our molecular genetic approach showing the need for an increase of risk levels at least on a factor of 3 for the heritable chromosome alterations detected by the ordinary cytogenetic monitoring).

Animals↗
PubMed2002

Isolated lissencephaly sequence with contiguous gene deletion detected by FISH analysis: a case report.

BACKGROUND: Lissencephaly is a clinically and genetically heterogeneous malformation of the brain, usually leading to a severe disabling condition and seizures. The recent discovery of molecular techniques and identification of lissencephaly genes (e.g. LISI and DCX) has allowed etiologic diagnosis of this disorder feasible. OBJECTIVE: To describe a patient with lissencephaly in whom fluorescence in situ hybridization (FISH) determined etiologic diagnosis, providing precise genetic counseling and possible prenatal diagnosis for the family. CLINICAL REPORT AND STUDY RESULTS: The authors report a 4 month-old girl who presented with intractable, generalized myoclonic seizures at I month of age. The patient was born at 37 weeks' gestation, to a G4P1A2 36-year-old woman. Chromosome analysis from amniotic fluid performed for advanced maternal age revealed normal karyotype. Pregnancy was complicated by polyhydramnios. Computed tomographic scan of the brain at age one month showed a total absence of gyral formation. FISH of the metaphase chromosome from the patient, using Smith-Magenis and Miller-Dieker/ILS probe showed two signals of Smith-Magenis probe but only one signal of Miller-Dieker/ILS probe, indicating a microdeletion of 17pl3.3 region including LIS1 gene. Hybridization of the ILS probe on the metaphase chromosome of both parents was normal. CONCLUSION: A confirmation of contiguous gene deletion in this patient lead to an etiologic diagnosis of lissencephaly. This information allowed precise genetic counseling, estimation of recurrent risk, and definite prenatal diagnosis available to the family. The authors suggest FISH 17p13.3 studies be performed in addition to a standard metaphase analysis in all patients with type I lissencephaly.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗
PubMed2003

[Monogenic hereditary diseases].

Monogenic disorders are caused by the inheritance of single gene mutations; alternatively, a monogenic disorder arises as a consequence of a de novo mutation in either the paternal or maternal germ line. The exponential increase in our understanding of the human genome has resulted in the localisation and cloning of a vast number of disease genes which has enabled the precise characterization of the underlying molecular defect in many of these disorders. Single nucleotide substitutions and microdeletions are the major types of disease-related mutations, but more complex mutations have also been described.

Genes, Dominant↗
PubMed2003

Mutational analysis of the nf2 tumour suppressor gene in three subtypes of primary human malignant mesotheliomas.

Fourteen primary human malignant mesothelioma (HMM) samples obtained from 14 patients were screened for point mutations and microdeletions/microinsertions in exons 1-16 of the chromosome 22q-located tumour suppressor gene neurofibromin 2 (nf2) by single strand conformation polymorphism (SSCP) analysis. In one tumour (7%) a 10 basepair microdeletion of exon 10 was detected by SSCP and subsequently characterised in detail by sequencing. Deletion of the second nf2 allele in laser-microdissected regions of the 10 bp mutation-harbouring tumour was demonstrated by denaturing gradient gel electrophoresis (DGGE) analysis. Simultaneous comparative genomic hybridisation (CGH) analysis also showed losses at chromosome 22q. Our data indicate that functional loss of the NF2 protein may be involved in the formation of a subset of HMMs.

Aged↗
PubMed2003

Partial deletions of the long arm of chromosome 13 associated with holoprosencephaly and the Dandy-Walker malformation.

Two patients with partial deletions of the long arm of chromosome 13, del(13)(13q21-q34) and del(13)(13q22-q33), respectively, multiple congenital anomalies including holoprosencephaly (HPE) and the Dandy-Walker malformation (DWM) are described. The occurrence of HPE and the DWM in both of these patients suggests that, in addition to ZIC2, which is important for normal development of the forebrain, there is at least one other dosage-sensitive gene in 13q22-q33 that plays an important role in brain development. The DWM is anatomically and developmentally distinct from HPE. The presence of a DWM in each of these two patients with partial deletions of the long arm of chromosome 13 suggests that haploinsufficiency at a locus in 13q22-q33 may cause this anomaly. These findings suggest that microdeletions in 13q22-q33 may be found in a proportion of patients with an apparently isolated DWM. Therefore, careful high-resolution cytogenetic analysis (550 band level or greater) of 13q22-q33 may be considered in these patients. Furthermore, future molecular studies of this region may reveal candidate gene loci for the DWM.

Chromosome Banding↗
PubMedDate not supplied

Smith-Magenis syndrome: report of one case.

Smith-Magenis syndrome (SMS) is a multiple congenital anomalies/mental retardation syndrome characterized by an interstitial deletion on the short arm of chromosome 17 involving the band p11.2. A 3-year-old girl was referred for evaluation of moderate psychomotor retardation and several behavioral problems including self-injuring behavior, hyperactivity, and sleep disturbance. Visual and hearing impairment, and brain abnormalities including ventriculomegaly and hypoplastic right transverse sinus, were detected. Routine cytogenetic study showed an apparent mosaicism of an interstitial deletion over the chromosomal region 17p11.2 in 65% metaphases. However, the microdeletion was found in all metaphases by fluorescence in situ hybridization study with the probe D17S29 (for Smith-Magenis critical region on 17p11.2). Her sleep disorder improved after the use of melatonin.

Abnormalities, Multiple↗
PubMed2003

[Diagnosis of cryptic chromosome aberrations].

BACKGROUND: Cryptic chromosome aberrations, i.e. those that are not observed by routine chromosome analysis (G-banding), can cause a plethora of developmental abnormalities, usually at least a combination of various dysmorphic signs and mental retardation. MATERIALS AND METHODS: We present the current molecular cytogenetic methods for detection of cryptic chromosome aberrations, with special emphasis on comparative genomic hybridisation (CGH), a DNA-based screening method. RESULTS: Using comparative genomic hybridisation with high-resolution analysis, we were able to detect a chromosome aberration in 10 % of patients found to have normal karyotypes by standard chromosome analysis. INTERPRETATION: Though the sensitivity of comparative genomic hybridisation is still insufficient for finding a deletion in most of the well-known microdeletion syndromes, the diagnostic yield of genomic imbalances is better than for all other laboratory investigations except routine G-banding.

Child↗
PubMed2003

Associated anomalies in asymmetric crying facies and 22q11 deletion.

Congenital asymmetric crying facies, a minor congenital anomaly due to unilateral absence or hypoplasia of the depressor anguli oris muscle, is associated at times with major congenital anomalies. A large number of asymmetric crying facies cases with chromosome 22q11 microdeletions have presently been reported. Fluorescence in situ hybridization (FISH) analysis for 22q11 deletion was performed on 8 infants with asymmetric crying facies. Five of our patients had at least one associated systemic anomaly. Two of 5 patients had conotruncal heart disease (Cayler cardiofacial syndrome). In three of the affected infants, we failed to reveal additional congenital malformation. The 22q11 deletion was present in only one patient. This baby had congenital hypoparathyroidism, severe neonatal hypocalcaemia and tetralogy of Fallot. We suggest, a 22q11 deletion should be excluded not in all cases but in cases with Cayler cardiofacial syndrome and in ACF associated with additional congenital anomalies.

Abnormalities, Multiple↗