51
|
Rossiter JP, Blakemore KJ, Kickler TS, Kasch LM, Khouzami AN, Pressman EK, Sciscione AC, Kazazian HH. The use of polymerase chain reaction to determine fetal RhD status. Am J Obstet Gynecol 1994; 171:1047-51. [PMID: 7943068 DOI: 10.1016/0002-9378(94)90032-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
OBJECTIVE Our purpose was (1) to establish the accuracy of a deoxyribonucleic acid amplification method in determination of RhD status in adult blood samples, including weak D variants (previously referred to as Du) and a D mosaic, and (2) to apply the method to determine fetal RhD status in alloimmunized pregnancies. STUDY DESIGN Twenty-five adult blood samples, including five weak D variants and one D mosaic, were analyzed with a polymerase chain reaction to determine RhD type. The method was then applied to amniotic fluid samples obtained by amniocentesis from three RhD-negative women with known RhD sensitization. RESULTS RhD type determined by polymerase chain reaction for all adult blood samples agreed with serologic typing results. All weak D variants and the D mosaic gave results consistent with RhD positivity. Fetal RhD status was determined in each of the three alloimmunized pregnancies, and obstetric management decisions were made on the basis of these results. CONCLUSIONS This polymerase chain reaction method allows rapid and accurate determinations of fetal RhD status by amniocentesis. Fetal blood sampling or serial amniocenteses may be avoided when the fetus is RhD negative, and plans for surveillance and intervention can be confidently made if the fetus is RhD positive. However, before the widespread use of this assay, its sensitivity and specificity must be established. Because weak D variants and a D mosaic demonstrated RhD-positive status by polymerase chain reaction, the method described is applicable to these RhD variants.
Collapse
|
52
|
Dombroski BA, Feng Q, Mathias SL, Sassaman DM, Scott AF, Kazazian HH, Boeke JD. An in vivo assay for the reverse transcriptase of human retrotransposon L1 in Saccharomyces cerevisiae. Mol Cell Biol 1994; 14:4485-92. [PMID: 7516468 PMCID: PMC358820 DOI: 10.1128/mcb.14.7.4485-4492.1994] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
L1 elements constitute a highly repetitive human DNA family (50,000 to 100,000 copies) lacking long terminal repeats and ending in a poly(A) tail. Some L1 elements are capable of retrotransposition in the human genome (Kazazian, H. H., Jr., C. Wong, H. Youssoufian, A. F. Scott, D. G. Phillips, and S.E. Antonarakis, Nature (London) 332:164-166, 1988). Although most are 5' truncated, a consensus sequence of complete L1 elements is 6 kb long and contains two open reading frames (ORFs) (Scott, A. F., B. J. Schmeckpeper, M. Abdelrazik, C. T. Comey, B. O'Hara, J. P. Rossiter, T. Cooley, P. Health, K. D. Smith, and L. Margolet, Genomics 1:113-125, 1987). The protein encoded by ORF2 has reverse transcriptase (RT) activity in vitro (Mathias, S. L., A. F. Scott, H. H. Kazazian, Jr., J. D. Boeke, and A. Gabriel, Science 254:1808-1810, 1991). Because L1 elements are so numerous, efficient methods for identifying active copies are required. We have developed a simple in vivo assay for the activity of L1 RT based on the system developed by Derr et al. (Derr, L. K., J. N. Strathern, and D. J. Garfinkel, Cell 67:355-364, 1991) for yeast HIS3 pseudogene formation. L1 ORF2 displays an in vivo RT activity similar to that of yeast Ty1 RT in this system and generates pseudogenes with unusual structures. Like the HIS3 pseudogenes whose formation depends on Ty1 RT, the HIS3 pseudogenes generated by L1 RT are joined to Ty1 sequences and often are part of complex arrays of Ty1 elements, multiple HIS3 pseudogenes, and hybrid Ty1/L1 elements. These pseudogenes differ from those previously described in that there are base pairs of unknown origin inserted at several of the junctions. In two of three HIS3 pseudogenes studied, the L1 RT appears to have jumped from the 5' end of a Ty1/L1 transcript to the poly(A) tract of the HIS3 RNA.
Collapse
|
53
|
Balta G, Brickner HE, Takegawa S, Kazazian HH, Papayannopoulou T, Forget BG, Atweh GF. Increased expression of the G gamma and A gamma globin genes associated with a mutation in the A gamma enhancer. Blood 1994; 83:3727-37. [PMID: 7515719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
We have previously described a unique type of delta beta-thalassemia in a Chinese family characterized by increased expression of the G gamma and A gamma fetal globin genes in the absence of a large deletion in the beta-globlin gene cluster. Our earlier study of the beta-globin gene on this delta beta-thalassemia chromosome showed a promoter mutation in the TATA box. In this report, we describe the results of our study of the fetal globin domain of this delta beta-thalassemia chromosome. We have cloned a 13-kb DNA fragment that includes the G gamma and the A gamma genes and the 3' A gamma enhancer element of this delta beta-thalassemia chromosome. DNA sequence analysis of the G gamma and A gamma-globin genes including their promoters did not show any mutations, but analysis of the putative enhancer element downstream from the A gamma-globin gene showed a C to T substitution 2,401 nucleotides downstream from the A gamma cap site. We performed DNA linkage analysis to determine if this mutation is unique to this chromosome or represents a common polymorphism. Our linkage analysis showed that this mutation is not a common polymorphism and that it is also not an intrinsic part of the haplotype of the chromosome on which it was found. We also studied the interaction of nuclear proteins from erythroid and nonerythroid cells with the DNA sequences surrounding this mutation. We have shown by in vitro DNase I footprinting that this mutation falls within a region that is occupied by a novel DNA-binding protein that binds to this site in nuclear extracts from erythroid, but not nonerythroid cells. The binding of this nuclear protein to DNA appears to be dependent on GATA-1 binding to an adjacent GATA-1 site. We have also developed a new functional assay to compare the activity of the normal and mutant A gamma enhancer elements in erythroid cells. Analysis of the activity of the mutant enhancer shows that the mutation completely eliminates all enhancer activity in this assay. These findings suggest that this mutation of the A gamma enhancer on a chromosome that carries a partially inactivated beta-globin gene may be responsible for the increased expression of both gamma-globin genes seen in this condition.
Collapse
|
54
|
Holmes SE, Dombroski BA, Krebs CM, Boehm CD, Kazazian HH. A new retrotransposable human L1 element from the LRE2 locus on chromosome 1q produces a chimaeric insertion. Nat Genet 1994; 7:143-8. [PMID: 7920631 DOI: 10.1038/ng0694-143] [Citation(s) in RCA: 172] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We have found a 2 kilobase insertion containing a rearranged L1 element in the dystrophin gene of a muscular dystrophy patient. We cloned the precursor of this insertion, the second known active human L1 element. The locus, LRE2, has one allele derived from the patient which matches the insertion sequence exactly. LRE2 has a perfect 13-15 bp target site duplication, two open reading frames, and an unusual 21 bp truncation of the 5' end, suggesting that a slightly truncated element can still retrotranspose. It differs from LRE1 by approximately 0.7%. There is an L1 element at LRE2 on approximately 66% of human chromosomes 1q, and the element is absent from chimpanzee and gorilla genomes. These data demonstrate that multiple active L1 elements exist in the human genome, and that a readthrough transcript of an active element is capable of retrotransposition.
Collapse
|
55
|
Pulver AE, Karayiorgou M, Lasseter VK, Wolyniec P, Kasch L, Antonarakis S, Housman D, Kazazian HH, Meyers D, Nestadt G. Follow-up of a report of a potential linkage for schizophrenia on chromosome 22q12-q13.1: Part 2. AMERICAN JOURNAL OF MEDICAL GENETICS 1994; 54:44-50. [PMID: 7909990 DOI: 10.1002/ajmg.1320540109] [Citation(s) in RCA: 111] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
A collaboration involving four groups of investigators (Johns Hopkins University/Massachusetts Institute of Technology; Medical College of Virginia/The Health Research Board, Dublin; Institute of Psychiatry, London/University of Wales, Cardiff; Centre National de la Recherche Scientifique, Paris) was organized to confirm results suggestive of a schizophrenia susceptibility locus on chromosome 22 identified by the JHU/MIT group after a random search of the genome. Diagnostic, laboratory, and analytical reliability exercises were conducted among the groups to ensure uniformity of procedures. Data from genotyping of 3 dinucleotide repeat polymorphisms (at the loci D22S268, IL2RB, D22S307) for a combined replication sample of 256 families, each having 2 or more affected individuals with DNA, were analysed using a complex autosomal dominant model. This study provided no evidence for linkage or heterogeneity for the region 22q12-q13 under this model. We conclude that if this region confers susceptibility to schizophrenia, it must be in only a small proportion of families. Collaborative efforts to obtain large samples must continue to play an important role in the genetic search for clues to complex psychiatric disorders such as schizophrenia.
Collapse
|
56
|
Pulver AE, Karayiorgou M, Wolyniec PS, Lasseter VK, Kasch L, Nestadt G, Antonarakis S, Housman D, Kazazian HH, Meyers D. Sequential strategy to identify a susceptibility gene for schizophrenia: report of potential linkage on chromosome 22q12-q13.1: Part 1. AMERICAN JOURNAL OF MEDICAL GENETICS 1994; 54:36-43. [PMID: 8178837 DOI: 10.1002/ajmg.1320540108] [Citation(s) in RCA: 281] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
To identify genes responsible for the susceptibility for schizophrenia, and to test the hypothesis that schizophrenia is etiologically heterogeneous, we have studied 39 multiplex families from a systematic sample of schizophrenic patients. Using a complex autosomal dominant model, which considers only those with a diagnosis of schizophrenia or schizoaffective disorder as affected, a random search of the genome for detection of linkage was undertaken. Pairwise linkage analyses suggest a potential linkage (LRH = 34.7 or maximum lod score = 1.54) for one region (22q12-q13.1). Reanalyses, varying parameters in the dominant model, maximized the LRH at 660.7 (maximum lod score 2.82). This finding is of sufficient interest to warrant further investigation through collaborative studies.
Collapse
|
57
|
Reiss AL, Kazazian HH, Krebs CM, McAughan A, Boehm CD, Abrams MT, Nelson DL. Frequency and stability of the fragile X premutation. Hum Mol Genet 1994; 3:393-8. [PMID: 8012350 DOI: 10.1093/hmg/3.3.393] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Although considered the most common heritable cause of neurodevelopmental disability, precise prevalence figures for the FMR1 mutation in the general population are lacking. Since no fragile X premutation alleles have yet been observed to originate from FMR1 alleles within the normal size range, there is also little information available about the origin of the fragile X premutation and mechanisms leading to instability of the FMR1 trinucleotide repeat region. In this study, 977 genetically unrelated individuals from families unselected for mental retardation or fragile X were analyzed with Southern blot analysis for the presence of FMR1 mutations. A subgroup of subjects with evidence of a large CGG repeat number, and any available relatives, were further studied with PCR to investigate the stability of the trinucleotide repeat segment of FMR1. One subject had a 75 repeat length which was unstable (increased in size) when passed to subsequent generations. This includes one male descendent who had a premutation/full mutation mosaic pattern. Two other alleles with > or = 46 repeats from different subjects were also found to be unstable and increased in size in subsequent generations. Considering all three unstable alleles to be indicative of an evolving or actual premutation, the estimated frequency of the fragile X premutation is one in 510 X chromosomes. However, since 11 other alleles with > or = 46 repeats were found to be stable through at least one meiotic transmission, repeat length appears to be an important but not sufficient condition leading to instability of the FMR1 gene.
Collapse
|
58
|
Garewal G, Fearon CW, Warren TC, Marwaha N, Marwaha RK, Mahadik C, Kazazian HH. The molecular basis of beta thalassaemia in Punjabi and Maharashtran Indians includes a multilocus aetiology involving triplicated alpha-globin loci. Br J Haematol 1994; 86:372-6. [PMID: 8199027 DOI: 10.1111/j.1365-2141.1994.tb04742.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
We have analysed 201 beta-thalassaemia (beta-thal) genes from natives of the Punjab (156) and Maharashtra states of India and found the causative mutation in 200 of them. The most common beta-globin gene mutations differed significantly between these two groups and between these groups and Indian immigrants in the U.S.A. and the U.K. In the Punjabi Indians the IVS-1, nt 1 (G-T) mutation accounted for nearly one-quarter of beta-thal genes, whereas it was 5% or less in the other groups. Likewise, the cap + 1 mutation was much more prevalent in the Punjabis, whereas the nonsense codon 15 allele had a higher frequency in the Maharashtrans of the Bombay region. The common IVS-1, nt5 allele had a frequency of 60% of beta-thal genes in the Maharastrans, 35% in North American immigrants, and only 23% in the Punjabis. Two-thirds of all beta-thal genes in Punjab were found in the merchant caste (Khatri-Arora), whereas the menial caste (Shudra) was highly represented among those with beta-thal genes in Maharashtra. Two novel beta-globin alleles were each found once; a frameshift codon 55 (+A) in Maharashtrans and a frameshift codons 47-48 (+ATCT) in Punjabis. Of three Punjabi patients with beta-thal intermedia in whom only a single severe beta-globin gene mutation was found, two had six alpha-globin genes (homozygosity for a triplicated alpha-globin locus) instead of the normal alpha-globin gene number of four. Thus, these two individuals had a multilocus aetiology of beta-thal and their parents have the unusual recurrence risk of 1 in 8 for conceiving a third with beta-thal intermedia. Since 15% of 126 alpha-globin clusters studies in Punjabis contained either single (10%) or triplicated (5%) alpha-globin genes, the alpha-globin gene number is a frequent modifier of the phenotype of beta-thal in this ethnic group.
Collapse
|
59
|
Kazazian HH. The New Genetics. Science 1994; 263:255-6. [PMID: 17839190 DOI: 10.1126/science.263.5144.255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
|
60
|
Lakich D, Kazazian HH, Antonarakis SE, Gitschier J. Inversions disrupting the factor VIII gene are a common cause of severe haemophilia A. Nat Genet 1993; 5:236-41. [PMID: 8275087 DOI: 10.1038/ng1193-236] [Citation(s) in RCA: 511] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Mutations in the factor VIII gene have been discovered for barely more than half of the examined cases of severe haemophilia A. To account for the unidentified mutations, we propose a model based on the possibility of recombination between homologous sequences located in intron 22 and upstream of the factor VIII gene. Such a recombination would lead to an inversion of all intervening DNA and a disruption of the gene. We present evidence to support this model and describe a Southern blot assay that detects the inversion. These findings should be valuable for genetic prediction of haemophilia A in approximately 45% of families with severe disease.
Collapse
|
61
|
Dombroski BA, Scott AF, Kazazian HH. Two additional potential retrotransposons isolated from a human L1 subfamily that contains an active retrotransposable element. Proc Natl Acad Sci U S A 1993; 90:6513-7. [PMID: 8393568 PMCID: PMC46962 DOI: 10.1073/pnas.90.14.6513] [Citation(s) in RCA: 100] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
We have previously reported the isolation of a human retrotransposable L1 element. This element, allele L1.2B at the LRE-1 locus of chromosome 22, was shown by nucleotide sequence identity to be the direct precursor of a de novo retrotransposition event into the factor VIII gene on the X chromosome, resulting in hemophilia A in patient JH-27. We now report the isolation of the two remaining full-length members of the subfamily of L1 elements closely related to L1.2B present in the genome of the mother of JH-27. Since these elements, L1.3 and L1.4, are very similar in sequence to L1.2B and contain both open reading frames 1 and 2 intact, they are also likely to be active retrotransposable elements. This suggests that certain L1 subfamilies may contain multiple active elements.
Collapse
|
62
|
Kazazian HH. The molecular basis of hemophilia A and the present status of carrier and antenatal diagnosis of the disease. Thromb Haemost 1993; 70:60-2. [PMID: 8236115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
|
63
|
McGinniss MJ, Rosenberg C, Stetten G, Schinzel AA, Binkert F, Petersen MB, Kearns WG, Kazazian HH, Pearson PL, Antonarakis SE. Unbalanced translocation, t(18;21), detected by fluorescence in situ hybridization (FISH) in a child with 18q- syndrome and a ring chromosome 21. AMERICAN JOURNAL OF MEDICAL GENETICS 1993; 46:647-51. [PMID: 8362906 DOI: 10.1002/ajmg.1320460609] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
We report on an 8-year-old girl with minor anomalies consistent with 18q- syndrome and mild developmental delay. Initially cytogenetics showed a terminal deletion of chromosome 21 with mosaicism for a small ring chromosome 21 as the only apparent karyotypic abnormality: mos 45,XX,-21/46,XX,+r(21) (48%/52%). Further studies including FISH and DNA analysis demonstrated a de novo unbalanced translocation of chromosomes 18 and 21 with the likely breakpoints in 18q23 and 21q21.1. Most of 21q was translocated to the distal long arm of one chromosome 18, and this derivative 18 appeared to lack 18q23-qter. The small ring chromosome 21 [r(21)], present in only 52% of the patient's blood lymphocytes, did not appear to be associated with the abnormal phenotype since all 13 chromosome 21 markers that were examined in genomic DNA were present in 2 copies, and the phenotype of the patient was consistent with the 18q- syndrome. The karyotype was reinterpreted as mos 45,XX,-18,-21,+der(18) t(18;21) (q23;q21.1)/46,XX,-18,-21,+der(18) t(18;21) (q23;q21.1), +r(21) (p13q21.1) (48%/52%). These results demonstrate the power of FISH in conjunction with DNA analysis for examination of chromosome rearrangements that may be misclassified by traditional cytogenetic studies alone.
Collapse
|
64
|
Kazazian HH, Scott AF. "Copy and paste" transposable elements in the human genome. J Clin Invest 1993; 91:1859-60. [PMID: 8387533 PMCID: PMC288176 DOI: 10.1172/jci116400] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
|
65
|
Migeon BR, McGinniss MJ, Antonarakis SE, Axelman J, Stasiowski BA, Youssoufian H, Kearns WG, Chung A, Pearson PL, Kazazian HH. Severe hemophilia A in a female by cryptic translocation: order and orientation of factor VIII within Xq28. Genomics 1993; 16:20-5. [PMID: 8486358 DOI: 10.1006/geno.1993.1134] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We report studies of a female with severe hemophilia A resulting from a complex de novo translocation of chromosomes X and 17 (46,X,t(X;17)). Somatic cell hybrids containing the normal X, the der(X), or the der(17) were analyzed for coagulation factor VIII (F8C) sequences using Southern blots and polymerase chain reaction. The normal X, always late replicating, contains a normal F8C gene, whereas the der(X) has no F8C sequences. The der(17) chromosome containing Xq24-Xq28 carries a functional G6PD locus and a deleted F8C allele that lacks exons 1-15. Also, it lacks the DXYS64-X locus, situated between the F8C locus and the Xq telomere. These results indicate that a cryptic breakpoint within Xq28 deleted the 5' end of F8C, but left the more proximal G6PD locus intact on the der(17) chromosome. As the deleted segment includes the 5' half of F8C as well as the subtelomeric DXYS64 locus, F8C must be oriented on the chromosome with its 5' region closest to the telomere. Therefore, the order of these loci is Xcen-G6PD-3'F8C-5'F8C-DXYS64-Xqtel. The analysis of somatic cell hybrids has elucidated the true nature of the F8C mutation in the proband, revealing a more complex rearrangement (three chromosomes involved) than that expected from cytogenetic analysis, chromosome painting, and Southern blots. A 900-kb segment within Xq28 has been translocated to another autosome. Hemophilia A in this heterozygous female is due to the decapitation of the F8C gene on the der(17) and inactivation of the intact allele on the normal X.
Collapse
|
66
|
McGinniss MJ, Kazazian HH, Hoyer LW, Bi L, Inaba H, Antonarakis SE. Spectrum of mutations in CRM-positive and CRM-reduced hemophilia A. Genomics 1993; 15:392-8. [PMID: 8449505 DOI: 10.1006/geno.1993.1073] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Hemophilia A is due to the functional deficiency of factor VII (FVIII, gene locus F8C). Although half the patients have no detectable FVIII protein in their plasma, the more rare patients (approximately 5%) have normal levels of a dysfunctional FVIII and are termed cross-reacting material (CRM)-positive. More commonly (approximately 45%), patients have plasma FVIII protein reduced to an extent roughly comparable to the level of FVIII activity and are designated CRM-reduced. We used denaturing gradient gel electrophoresis to screen for mutations within the F8C gene of 11 patients (6 CRM-positive, 5 CRM-reduced) and identified 9 different mutations in 9 patients after analyses of all 26 exons, the promoter region, and the polyadenylation site. Six mutations have not been described previously. Five were missense (Ser289Leu, Ser558Phe, Val634Ala, Val634-Met, Asn1441Lys), and the sixth was a 3-bp deletion (delta Phe652). A review of the literature and the assay of FVIII antigen in 5 hemophilia A patients with previously identified missense mutations from this laboratory yielded a total of 20 other unique CRM-reduced and CRM-positive mutations. Almost all CRM-positive/reduced mutations (24/26) were missense, and many (12/26) occurred at CpG dinucleotides. We examined 19 missense mutations for evolutionary conservation using the portions of the porcine and murine F8C sequences that are known, and 18/19 amino acid residues altered by mutation in these patients were conserved. Almost 50% of mutations (11/26) clustered in the A2 domain, suggesting that this region is critical for the function of FVIII.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
|
67
|
Hussein IR, Temtamy SA, el-Beshlawy A, Fearon C, Shalaby Z, Vassilopoulos G, Kazazian HH. Molecular characterization of beta-thalassemia in Egyptians. Hum Mutat 1993; 2:48-52. [PMID: 8477263 DOI: 10.1002/humu.1380020109] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We sought to determine the spectrum of mutations producing beta-thalassemia in Egypt using genomic PCR and a variety of mutation-screening procedures. Thirty-four beta-thalassemia and three Hb S/beta-thalassemia patients originating from different regions of Egypt were studied, and the causative mutation was found in 69 of 71 (97%) beta-thalassemia genes. Four mutations accounted for 78% of beta-thalassemia genes in this population; IVS-1, nt 110 (41%), IVS-1 nt 6 (13%), IVS-1, nt 1 (13%), and IVS-2, nt 848 (11%). The latter allele, a C-A mutation at the third nucleotide of an acceptor site consensus sequence, has been described previously only in one Egyptian, one Iranian, one Tunisian, and one Black American patient. Nine other alleles each accounted for 1-3% of beta-thalassemia genes. Among these was one codon 27 allele (Hb Knossos), two frameshift 106/107 alleles previously seen only in a Black American, and a rarely observed mutation in the distal promoter region of the beta-globin gene, -87 (C-A). Our results suggest that from a molecular genetic standpoint a beta-thalassemia prevention program based on carrier screening and prenatal diagnosis can be implemented in Egypt. In couples at risk for beta-thalassemia, the causative mutation should be identifiable in both members in 92% and in one member in the remaining 8%.
Collapse
|
68
|
Oppenheim A, Oron V, Filon D, Fearon CC, Rachmilewitz EA, Kazazian HH, Rund D. Sporadic alleles, including a novel mutation, characterize beta-thalassemia in Ashkenazi Jews. Hum Mutat 1993; 2:155-7. [PMID: 8318995 DOI: 10.1002/humu.1380020219] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
|
69
|
Miller M, Boehm C, Cotton M, Kazazian HH. Usefulness of a CACA repeat polymorphism in genotype assignments in Duchenne/Becker muscular dystrophy. AMERICAN JOURNAL OF MEDICAL GENETICS 1992; 44:473-6. [PMID: 1442890 DOI: 10.1002/ajmg.1320440417] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
RFLP analysis in Duchenne/Becker muscular dystrophy (D/BMD) has been limited by the lack of informative marker loci at the 3' end of the dystrophin gene. Recently a CACA repeat polymorphism was described in the 3' untranslated end of the dystrophin gene which we have found helpful in genotype assignments of D/BMD families when an RFLP approach is required. The CACA repeat marker has 2 common alleles (1 and 2) that are easily visualized by a nonradioactive PCR method followed by polyacrylamide gel electrophoresis. We present 2 families which demonstrate the use of this polymorphism. Since 35-50% of females are heterozygous, this locus is a useful marker in RFLP analysis of D/BMD families.
Collapse
|
70
|
Economou EP, Kazazian HH, Antonarakis SE. Detection of mutations in the factor VIII gene using single-stranded conformational polymorphism (SSCP). Genomics 1992; 13:909-11. [PMID: 1639429 DOI: 10.1016/0888-7543(92)90189-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
|
71
|
Aly AM, Higuchi M, Kasper CK, Kazazian HH, Antonarakis SE, Hoyer LW. Hemophilia A due to mutations that create new N-glycosylation sites. Proc Natl Acad Sci U S A 1992; 89:4933-7. [PMID: 1594597 PMCID: PMC49202 DOI: 10.1073/pnas.89.11.4933] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
In studying the molecular defects responsible for cross-reacting material-positive hemophilia A, we have identified two patients in whom the nonfunctional factor VIII-like protein has abnormal, slower-moving heavy or light chains on SDS/PAGE. Both patients have severe hemophilia A (less than 1% of normal factor VIII activity) with a normal plasma level of factor VIII antigen. The molecular defects were identified by denaturing gradient gel electrophoresis screening of PCR-amplified products of the factor VIII-coding DNA sequence followed by nucleotide sequencing of the abnormal PCR products. In patient ARC-21, a methionine-to-threonine substitution at position 1772 in the factor VIII light chain creates a potential new N-glycosylation site at asparagine-1770. In patient ARC-22, an isoleucine-to-threonine substitution at position 566 creates a potential new N-glycosylation site at asparagine-564 in the A2 domain of the factor VIII heavy chain. The mobility of these chains on SDS/PAGE was normal after N-Glycanase digestion and procoagulant activity was generated--to a maximum of 23% and 45% of control normal plasma. Abnormal N-glycosylation, blocking factor VIII procoagulant activity, represents a newly recognized mechanism for the pathogenesis of severe hemophilia A.
Collapse
|
72
|
Kazazian HH, Dowling CE, Hurwitz RL, Coleman M, Stopeck A, Adams JG. Dominant thalassemia-like phenotypes associated with mutations in exon 3 of the beta-globin gene. Blood 1992; 79:3014-8. [PMID: 1586746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Mutations producing beta-thalassemia reach individual gene frequencies greater than .01 in malarial-endemic regions because beta-thalassemia trait individuals have increased genetic fitness over that of normal individuals. Exon 3 of the beta-globin gene has been relatively spared as a site of common beta-thalassemia mutations. Frameshifts caused by the loss of a single nucleotide and nonsense mutations produce beta-thalassemia trait when they occur in exons 1 and 2. In contrast, they usually produce chronic hemolytic anemia when present in exon 3. Certain missense mutations in exon 3 produce unstable globins and thalassemia intermedia with hemolysis in heterozygotes. Here we report two new mutations in exon 3 of the beta-globin gene. One is a single nucleotide deletion in codon 109 in a 78-year-old Lithuanian with chronic hemolytic anemia and features of thalassemia. It leads to an abnormal globin (beta Manhattan) that is elongated to 156 amino acids. The second is a CAG-CGG missense mutation at codon 127 that causes a Gln----Pro substitution (beta Houston) and a thalassemia intermedia with hemolysis in three generations of a British-American family. Although the clinical phenotypes of these two patients differed little, differences in globin-synthetic ratios were significant, presumably reflecting differences in the ability of each abnormal beta-globin to form alpha beta dimers. The paucity of high-frequency exon 3 mutations and their worldwide distribution is likely attributable to their phenotypic severity and loss of increased genetic fitness vis-a-vis malaria.
Collapse
|
73
|
Rund D, Dowling C, Najjar K, Rachmilewitz EA, Kazazian HH, Oppenheim A. Two mutations in the beta-globin polyadenylylation signal reveal extended transcripts and new RNA polyadenylylation sites. Proc Natl Acad Sci U S A 1992; 89:4324-8. [PMID: 1374896 PMCID: PMC49074 DOI: 10.1073/pnas.89.10.4324] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Two mutations in the beta-globin poly(A) signal were identified in Israeli patients with beta +-thalassemia by sequence analysis following PCR. One is a point mutation (AATAAA----AATAAG) and the other is a 5-base-pair deletion (AATAAA----A----). The mutant genes were used to investigate the function of the poly(A) signal in vivo and to evaluate the mechanism whereby these mutations lead to a thalassemic phenotype. Analysis of RNA derived from peripheral blood demonstrated the presence of elongated RNA species in patients carrying either mutation. Other aspects of RNA processing (initiation, splicing) were unimpaired. RNA obtained from the patients carrying the point mutation contained four discrete, extended RNA species, 1500-2900 nucleotides long, which were found to be polyadenylated. Some normal cleavage-polyadenylylation was also observed. The 5-base-pair deletion completely abolished cleavage at the normal site. This deletion mutation resulted in a phenotype of beta +-thalassemia, thus providing evidence that the extended mRNAs are translatable in vivo. Furthermore, additional transcripts, greater than 5 kilobases, presumably mRNA precursors, were found in all RNA samples, including those of nonthalassemic controls. The extended transcripts of the poly(A) mutants, together with the high molecular weight precursors, suggest that the human beta-globin gene transcription unit is significantly longer than previously recognized.
Collapse
|
74
|
Renda M, Maggio A, Warren TC, Kazazian HH. Detection of an IVS-1 3' end (G-C) beta-thalassemia mutation in the AG invariant dinucleotide of the acceptor splice site in a Sicilian subject. Genomics 1992; 13:234-5. [PMID: 1577489 DOI: 10.1016/0888-7543(92)90232-h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
|
75
|
McGinniss MJ, Kazazian HH, Stetten G, Petersen MB, Boman H, Engel E, Greenberg F, Hertz JM, Johnson A, Laca Z. Mechanisms of ring chromosome formation in 11 cases of human ring chromosome 21. Am J Hum Genet 1992; 50:15-28. [PMID: 1346075 PMCID: PMC1682523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/25/2023] Open
Abstract
We studied the mechanism of ring chromosome 21 (r(21)) formation in 13 patients (11 unique r(21)s), consisting of 7 from five families with familial r(21) and 6 with de novo r(21). The copy number of chromosome 21 sequences in the rings of these patients was determined by quantitative dosage analyses for 13 loci on 21q. Nine of 11 r(21)s, including the 5 familial r(21)s, showed no evidence for duplication of 21q sequences but did show molecular evidence of partial deletion of 21q. These data were consistent with the breakage and reunion of short- and long-arm regions to form the r(21), resulting in deletion of varying amounts of 21q22.1 to 21qter. The data from one individual who had a Down syndrome phenotype were consistent with asymmetric breakage and reunion of 21q sequences from an intermediate isochromosome or Robertsonian translocation chromosome as reported by Wong et al. Another patient, who also exhibited Down syndrome, showed evidence of a third mechanism of ring formation. The likely initial event was breakage and reunion of the short and long arms, resulting in a small r(21), followed by a sister-chromatid exchange resulting in a double-sized and symmetrically dicentric r(21). The phenotype of patients correlated well with the extent of deletion or duplication of chromosome 21 sequences. These data demonstrate three mechanisms of r(21) formation and show that the phenotype of r(21) patients varies with the extent of chromosome 21 monosomy or trisomy.
Collapse
|