A new TaqI polymorphism of the complement factor B gene.
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Chromosomes, Human, Pair 6↗
Biomedical subjects
N Ghanem
Publications and source records attributed to N Ghanem.
Definition of the RFLP alleles in the human immunoglobulin IGHG gene locus.
In order to define more precisely the polymorphism of the human immunoglobulin IGHG (C gamma) genes and, consequently, to understand the structure and evolution of this multigene family, we have investigated the Restriction Fragment Length Polymorphisms (RFLP) of the IGHG genes in 113 unrelated individuals and 18 families. Using the restriction enzymes Bam HI, Sac I and Eco RI, and hybridization to a IGHG probe and to a specific IGHG3 (C gamma 3) probe, we describe 47 different restriction fragments (RF) in the IGHG locus, allowing us to define at least 15 RFLP alleles for the different IGHG genes. Our data demonstrate that the restriction fragment length polymorphism is occasionally due to the presence or absence of a given restriction site as a consequence of a point mutation, such as the creation of an Eco RI site, at the codon 3 of exon 2 in one IGHG4 allele (IGHG4*D2). However, most of the RFLP we observed seem to result from the insertion or deletion of a few hundred base pairs as illustrated by the IGHG3 polymorphism.
Alleles↗
Restriction fragment haplotypes in the human immunoglobulin IGHG locus and their correlation with the Gm polymorphism.
Of the four human IgG subclass heavy chain (IGHG) genes, three--IGHG1, IGHG2 and IGHG3--have allelic forms which encode antigenic determinants called G1m, G2m and G3m allotypes for markers of the IgG1, IgG2 and IgG3 molecules. The alleles at these three closely linked loci are transmitted as Gm haplotypes, together with the IGHG4 and the IGHGP (or pseudo gamma) genes. Restriction Fragment Length Polymorphisms (RFLPs) have been described for all these IGHG genes, allowing us to define at least 15 RFLP alleles (N. Ghanem et al., Eur. J. Immunol. 1988. 18:1059). In this article, we determine unambiguously the Gm alleles and haplotypes and the associated RFLPs in French, Lebanese and Tunisian families, chosen for the various Gm phenotypes of their members, in order to correlate both these polymorphisms and to know the evolution of the IGHG multigene family. We were able to assign all the IGHG alleles to the Gm alleles and to their linked IGHG4 and IGHGP genes allowing us to define restriction fragment haplotypes of the IGHG gene family.
Alleles↗
Polymorphism of MHC class III genes: definition of restriction fragment linkage groups and evidence for frequent deletions and duplications.
The loci for the complement proteins BF and C2 and the two loci for C4 are closely linked to one another, as are the duplicated steroid 21 hydroxylase (21-OHase) genes to the C4A and C4B loci. The alleles of these four loci occur in specific combinations termed "complotypes". We have studied the gene frequencies of their different products in the Lebanese population and compared these values with those found in other populations. We observed a novel complotype (S B 4 6) in one family and a complotype with a so far undescribed variant of the C4A locus. Using several restriction fragment length polymorphisms (RFLPs), we have defined restriction fragment linkage groups. The combined use of C4 and 21-OHase probes allowed us to detect different types of deletions and duplications at these loci in the Lebanese population.
Chromosome Deletion↗
Polymorphism of immunoglobulin lambda constant region genes in populations from France, Lebanon and Tunisia.
Polymorphism of immunoglobulin lambda constant region (IGLC) genes has been studied in French, Lebanese and Tunisian people. The human IGLC polymorphisms appear as EcoRI restriction fragment length variations-8, 13, 18 or 23 kb-, these polymorphic fragments being related to a number of IGLC genes varying from six to nine per haploid genome. DNAs digested with the endonucleases EcoRI and HindIII were hybridized to a human IGLC probe and an immunoglobulin lambda intervening sequence region probe containing the J lambda 2 gene segment. Restriction fragments detected in Southern hybridizations were assigned to the IGLC locus map. Family studies allowed us to confirm the allelic nature of four of the different EcoRI restriction fragments observed. Frequencies of the corresponding alleles in French, Lebanese and Tunisian populations were determined and compared. The decrease of the 8-kb fragment (allele A1) frequency and, conversely, the increase of that of the 13-kb and 18-kb fragments (alleles A2 and A3) seemed to be correlated to a Negroid African contribution in the gene pool more important in Tunisia than in Lebanon.
Deoxyribonuclease EcoRI↗
New subgroups in the human T cell rearranging V gamma gene locus.
Two new V gamma genes in humans are described from rearrangement in T cell lines, which constitute single members of new V gene subgroups of the T-cell rearranging gamma (TRG gamma) locus. These two genes (herein designated as belonging to V gamma III and V gamma IV subgroups) are located between V gamma I/V gamma II subgroups and the constant (C) gamma genes. The existence of these new genes brings the number of different, potentially useable, human TRG V gamma genes to eight (excluding at least five pseudo V gamma genes) and the number of distinct subgroups to four. Polymorphism in the sequence of the V gamma II subgroup gene is also described and rearranged fragment sizes which make possible an unequivocal assignment of a V gamma rearrangement are given. These results extend previous conclusions of the inherited diversity of the human TRG V gamma locus.
Amino Acid Sequence↗
Polymorphism of the complement C3 gene in the Lebanese population.
The C3 protein polymorphism was studied in 300 unrelated Lebanese. The gene frequencies were calculated and compared with other populations. DNA samples digested with various endonucleases were hybridized with a C3 probe, which was found to detect a frequent Sac I restriction fragment length polymorphism (RFLP) and a less frequent Taq I RFLP in the Lebanese population, as well as in the French populations.
Alleles↗
A gamma 3 hinge region probe: first specific human immunoglobulin subclass probe.
We report the first specific human immunoglobulin subclass probe which was obtained by subcloning the gamma 3 hinge region. This specific gamma 3 probe allowed us to identify with certainty the C gamma 3 gene on Southern genomic blots, to describe the first C gamma 3 restriction fragment length polymorphism (EZZ gamma 3 RF) and to show that an IgG3 selective deficiency, previously described serologically, was not due to a deletion of the C gamma 3 gene. Such a probe should be particularly useful for screening libraries from individuals with IgG3 immunodeficiencies or presenting unusual C gamma 3 genes and, consequently, for studying the C gamma gene evolution.
Amino Acid Sequence↗
Thrombectomy discloses intravascular growth of chondroid liposarcoma mimicking a long distance vena cava thrombosis.
A 22-year-old woman with a newly detected chondroid liposarcoma located in the iliac muscle was diagnosed as having bilateral pulmonary embolism. Gadolinium-enhanced MRI further revealed a long distance thrombus reaching from the iliac vein to the right atrium. The thrombus was attributed to a hypercoagulability state which has been described for chondroid liposarcoma. High-dose chemotherapy with autologous stem cell support reduced the tumor burden and led to a symptom-free interval of 6 months. Despite therapeutic anticoagulation, repeated imaging showed no reduction or remodeling of the thrombus. However, when the thrombus progressed again, the patient underwent cardiac surgery and histology revealed the intravascular growth of the known chondroid liposarcoma. We conclude that in sarcoma patients intravascular tumor growth must be kept in mind when imaging is suggestive for thrombosis.
Adult↗
Whole-body MRI in comparison to skeletal scintigraphy in detection of skeletal metastases in patients with solid tumors.
AIM: To evaluate the diagnostic value of whole-body magnetic resonance imaging (MRI) and skeletal scintigraphy in the detection of skeletal metastases in patients with solid tumors. MATERIALS AND METHODS: One hundred and twenty-nine tumor patients were examined with whole-body MRI using coronal TIRM sequences for the different anatomical regions. Skeletal scintigraphy was performed with 99mTc-DPD. RESULTS: In 105/129 (81%) patients, the whole-body MRI and skeletal scintigraphy findings were concordant. In 56/129 (43%) patients, both imaging modalities excluded skeletal metastases. In 49/129 (38%) patients, whole-body MRI and skeletal scintigraphy revealed metastases, however whole-body MRI demonstrated more extensive disease in 22/49 (45%) cases. In 6/49 (12%) cases, skeletal scintigraphy was superior to whole-body MRI in detecting more skeletal metastases. In 24/129 (19%) cases, the imaging findings were discordant. In 15 cases, skeletal scintigraphy was negative, whereas whole-body MRI revealed skeletal metastases. In 9 cases, skeletal scintigraphy was positive, whereas whole-body MRI failed to detect these metastases. In 77/129 (60%) patients, whole-body MRI revealed additional tumor-related findings. CONCLUSION: Whole-body MRI, as a new staging method, is superior to skeletal scintigraphy with respect to the detection of skeletal metastases and the extent of metastastic disease. Furthermore, whole-body MRI yields additional tumor-related findings. Therefore, whole-body MRI should be performed as an alternative to skeletal scintigraphy for the assessment of skeletal metastases.
Adolescent↗
CFTR gene mutations in adults with disseminated bronchiectasis.
The severity and type of clinical manifestations are variable in patients with cystic fibrosis (CF). The respiratory syndromes in these patients consist of lung infections associated with disseminated bronchiectasis (DB), asthma, and chronic obstructive pulmonary disease. To investigate the possible involvement of the cystic fibrosis transmembrane conductance regulator (CFTR) gene in chronic pulmonary disease in adults, we studied 32 DB patients with a clinically isolated respiratory syndrome. Careful analysis of all the CFTR gene exons and their flanking regions revealed a significantly increased frequency of CFTR gene mutations in these patients. Thirteen CFTR gene mutations were identified in sixteen different alleles. Six of these mutations, which have previously been reported as CF defects, were found on nine alleles. A further four, two of which had not previously been described (D192N and 406-2 AdeltaC), are potentially disease-causing mutations. We also identified three rare substitutions (R31C, L997F, T1220I), which could be involved in mild CFTR gene disease. Four patients were compound heterozygotes, one carried two CFTR gene mutations (possibly allelic) and six were heterozygous for a mutation. These results indicate that CFTR gene mutations may play a role in bronchiectatic lung disease, possibly in a multifactorial context. These findings have implications for genetic counselling of DB patients and their families.
Adult↗