Property Summary

NCBI Gene PubMed Count 150
PubMed Score 46.62
PubTator Score 1994.06

Knowledge Summary


No data available


 MGI Phenotype (1)

Gene RIF (38)

25842369 In Portuguese beta-thalassemia carriers the HBG2 XmnI polymorphism is strongly associated with HbF levels.
25123009 Hemoglobin gamma G plays a role in modifying clinical symptoms of beta-thalassemia innorthern Thailand.
25084696 DNA polymorphisms at BCL11A, HBS1L-MYB and Xmn1-HBG2 site loci associated with fetal hemoglobin levels in sickle cell anemia patients from Northern Brazil.
24502349 Data indicate that the T to A conversion results in a leucine to histidine amino acid change at codon 105 of the (G)gamma-globin HBG2 gene and caused a hemoglobin (Hb) variant with lowered oxygen affinity.
24474642 Its polymorphism effects HbF, HbE, MCV and MCH levels in Thai HbE carriers.
23777413 Data suggest that segregation of BCL11A haplotype 2 indicating an involvement of this locus in Hb F expression.
23713742 Hb F is regulated in inherited bone marrow failure syndromes by Xmn1-HBG2, as it is in the haemoglobinopathies.
23284307 Our data suggest that a temporal repression mechanism is operative in the silencing of gamma-globin gene expression
22871617 the study demonstrated that Egyptian beta-thalessemia patients have low frequency of positivity for the Xmnl polymorphism whether in heterozygous (+/-) or homozygous (+/+) state
22825848 results establish SATB2 as a novel gamma-globin gene regulator and provide a glimpse of the differential and cooperative roles of SATB family proteins in modulating clustered genes transcription
21755589 although the prevalence of Xmn1-(G)gamma polymorphism is high in beta thalassemia intermedia patients, it alone could not predict clinical severity of disease
21609963 Chromatin looping between the Ggamma-globin gene and LCR HSs requires NF-E2.
21561349 We identified a missense mutation in the fetal Ggamma-globin gene (HBG2) in a father and daughter with transient neonatal cyanosis and anemia.
21123872 12 molecules in the unit cell describe a right-handed helical filament having no polarity, which is different from the filament composed of HbS fibers, which is the only other well characterized fiber of human hemoglobin
20688955 The recently identified chromatin factor Friend of Prmt1 (FOP) is a critical modulator of gamma-globin gene expression.
20602015 The polymorphisms -396_-391 del HBG2, -369 SNP HBG2 and -271 SNP HBG1 correlated with HbF levels, hence, it suggests an important role of HBG2 and HBG1 gene polymorphisms on the HbF synthesis.
20472475 Observational study of gene-disease association. (HuGE Navigator)
20439494 role of the hematopoietic transcription factor GATA-1, its cofactor FOG-1, and the associated chromatin remodeling complex NuRD in the developmental silencing of HBG1 and HBG2 gene expression
20113294 A G>C substitution at position 479 of the (G)gamma-globin gene results in a glutamic acid to glutamine substitution at codon 101 of the (G)gamma-globin chain, a new gamma chain variant that we have named Hb F-Zhejiang
19892574 No statistically significant difference in the frequency of positive XmnI(G)gamma polymorphism was observed between thalassemia intermedia and thalassemia major patients.
19861239 Data suggest the G gamma-globin promoter is activated by cJun via an upstream cAMP response element.
19050890 HBG2:g-109G>T mutation has a functional role in increasing HBG2 transcription and is responsible for the hereditary persistence of fetal hemoglobin phenotype observed in our index cases
18951049 Observational study of gene-disease association. (HuGE Navigator)
18932071 Observational study of gene-disease association. (HuGE Navigator)
18667698 Observational study of gene-disease association. (HuGE Navigator)
18467329 analysis of heme uptake from human methemoglobin by the iron-regulated surface determinants system of Staphylococcus aureus
18443038 These results suggest that the GATA motif under study has a functional role in silencing gamma-globin gene expression in adults.
18266208 Observational study of gene-disease association. (HuGE Navigator)
18096417 study reports 2 new forms of nondeletional hereditary persistence of fetal hemoglobin; the presence of a (G)gamma-196 C-->T in the first case and an (A)gamma-201 C-->T in the second was revealed
17916326 This work describes the study of the interactions of different hemoglobin variants HbA, HbE and HbF and the globin subunits of HbA with the two aminophospholipids in the presence and absence of cholesterol.
17365007 A determinant linked to the XmnI restriction site which effects Ggamma-globin gene expression (and Hemoglobin F production) is active in beta-Thalassemic (anemic) adults but not in normal infants.
16956833 Observational study of gene-disease association. (HuGE Navigator)
15798211 3' flank of the Ggamma-globin gene contains multiple weak pause elements which, combined with the strong polyA signal the gene possesses, are likely to cause gradual termination across the 3' flank.
15476181 Data show that (G)Gamma-158(C-->T) had a strong association with moderately increased Hb F levels in beta-thalassemia heterozygotes in the Guangxi area of China.
14649320 in an Albanian family, two mutations of the gamma-globin promoter (for both HBG1 and HBG2) are assoicated in trans with a beta thal point mutation, that results in increased levels of HbF
11827978 Assembly of human hemoglobin (Hb) beta- and gamma-globin chains expressed in a cell-free system with alpha-globin chains to form Hb A and Hb F.
11132233 Observational study of gene-disease association and gene-gene interaction. (HuGE Navigator)
8911578 HIV-1 Tat inhibits the butyric acid-induced gamma-globin gene expression in human hematopoietic progenitor K562 cells

AA Sequence

ALSSRYH                                                                   141 - 147

Text Mined References (154)

PMID Year Title
25842369 2015 Polymorphic variations influencing fetal hemoglobin levels: association study in beta-thalassemia carriers and in normal individuals of Portuguese origin.
25123009 2014 The associations of SEA-alpha thalassemia 1, XmnI-Ggamma polymorphism and beta-globin gene mutations with the clinical severity of beta-thalassemia syndrome in northern Thailand.
25084696 2014 DNA polymorphisms at BCL11A, HBS1L-MYB and Xmn1-HBG2 site loci associated with fetal hemoglobin levels in sickle cell anemia patients from Northern Brazil.
24502349 2014 A new (G)?-globin variant causing low oxygen affinity: Hb F-Brugine/Feldkirch [(G)?105(G7)Leu?His; HBG2: c.317T>A].
24474642 2014 Effect of Swiss-type heterocellular HPFH from XmnI-G? and HBBP1 polymorphisms on HbF, HbE, MCV and MCH levels in Thai HbE carriers.
23777413 2013 Annotated definition of BCL11A and HMIP-2 haplotypes through the analysis of sicilian ?-thalassemia patients with high levels of fetal hemoglobin.
23713742 2013 Genetic regulation of fetal haemoglobin in inherited bone marrow failure syndromes.
23284307 2012 Mi2? is required for ?-globin gene silencing: temporal assembly of a GATA-1-FOG-1-Mi2 repressor complex in ?-YAC transgenic mice.
23186163 2013 Toward a comprehensive characterization of a human cancer cell phosphoproteome.
22871617 Prevalence of Xmnl G? polymorphism in Egyptian patients with ?-thalassemia major.
22825848 2012 The AT-rich DNA-binding protein SATB2 promotes expression and physical association of human (G)?- and (A)?-globin genes.
22516433 2012 Proteomic analysis of microvesicles from plasma of healthy donors reveals high individual variability.
21755589 2011 Xmn1-G ? polymorphism and clinical predictors of severity of disease in ?-thalassemia intermedia.
21609963 2011 The distinctive roles of erythroid specific activator GATA-1 and NF-E2 in transcription of the human fetal ?-globin genes.
21561349 2011 A hemoglobin variant associated with neonatal cyanosis and anemia.
21269460 2011 Initial characterization of the human central proteome.
21123872 2010 Structure of a crystal form of human methemoglobin indicative of fiber formation.
20688955 2010 Fetal globin expression is regulated by Friend of Prmt1.
20602015 2010 Promoter region sequence differences in the A and G gamma globin genes of Brazilian sickle cell anemia patients.
20472475 2010 The XmnI (G)gamma polymorphism influences hemoglobin F synthesis contrary to BCL11A and HBS1L-MYB SNPs in a cohort of 57 beta-thalassemia intermedia patients.
20439494 2010 Role of the GATA-1/FOG-1/NuRD pathway in the expression of human beta-like globin genes.
20183929 2010 A genome-wide association identified the common genetic variants influence disease severity in beta0-thalassemia/hemoglobin E.
20113294 2010 Hb F-Zhejiang: a Hb F variant due to a novel Ggamma mutation [Ggamma101(G3)Glu-->Gln, GAG>CAG] detected in a Chinese newborn.
19958193 2009 Two abnormal fetal hemoglobins found in the Sardinian population: the new Hb F-Osilo [(A)gamma119(GH2)Gly-->Ser, GGC > AGC] and Hb F-Paulinia [(G)gamma80(EF4)Asp-->Tyr, GAT > TAT] already described in the Brazilian population.
19892574 Frequency of positive XmnIGgamma polymorphism and coinheritance of common alpha thalassemia mutations do not show statistically significant difference between thalassemia major and intermedia cases with homozygous IVSII-1 mutation.
19861239 2010 cJun modulates Ggamma-globin gene expression via an upstream cAMP response element.
19065339 2008 Neonatal cyanosis due to a novel fetal hemoglobin: Hb F-Circleville [Ggamma63(E7)His-->Leu, CAT>CTT].
19050890 2009 The Hellenic type of nondeletional hereditary persistence of fetal hemoglobin results from a novel mutation (g.-109G>T) in the HBG2 gene promoter.
18951049 Molecular, hematological and clinical aspects of thalassemia major and thalassemia intermedia associated with Hb E-beta-thalassemia in Northeast Thailand.
18932071 2008 Molecular basis of thalassemia intermedia in Iran.
18667698 2008 DNA polymorphisms at the BCL11A, HBS1L-MYB, and beta-globin loci associate with fetal hemoglobin levels and pain crises in sickle cell disease.
18467329 2008 Pathway for heme uptake from human methemoglobin by the iron-regulated surface determinants system of Staphylococcus aureus.
18443038 2008 A T-to-G transversion at nucleotide -567 upstream of HBG2 in a GATA-1 binding motif is associated with elevated hemoglobin F.
18266208 2008 Variation and heritability of Hb F and F-cells among beta-thalassemia heterozygotes in Hong Kong.
18096417 G gamma-196 C-->T, A gamma-201 C-->T: two novel mutations in the promoter region of the gamma-globin genes associated with nondeletional hereditary persistence of fetal hemoglobin in Greece.
17916326 2008 Membrane interactions of hemoglobin variants, HbA, HbE, HbF and globin subunits of HbA: effects of aminophospholipids and cholesterol.
17365007 2007 Developmental effect of the XmnI site on Ggamma-globin gene expression among newborn Hb F-Malta-I [Ggamma117(G19)His-->Arg, CAT-->CGT] heterozygotes and adult beta+ -Thalassemia homozygotes.
16956833 2006 Influence of Ggamma-158C --> and beta- (AT)x(T)y globin gene polymorphisms on HbF levels in Italian beta-thalassemia carriers and wild-type subjects.
16370494 2005 A new G(gamma) chain variant: Hb F-Bron [gamma20(B2)val-->Ala].
15798211 2005 Strong polyadenylation and weak pausing combine to cause efficient termination of transcription in the human Ggamma-globin gene.
15645283 2005 Severe hereditary haemolytic anaemia in a Caucasian newborn: a new fetal haemoglobin variant Hb F-Bonheiden ((G)gamma 38(C4) Thr-->Pro).
15489334 2004 The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC).
15476181 2004 [Beta-thalassemia mutations and single nucleotide polymorphism at -158 of Ggamma-globin gene associated with altered levels of Hb F in beta-thalassemia heterozygotes].
15231748 2004 Functional proteomics mapping of a human signaling pathway.
15108284 2004 Real-time PCR for single-cell genotyping in sickle cell and thalassemia syndromes as a rapid, accurate, reliable, and widely applicable protocol for preimplantation genetic diagnosis.
14702039 2004 Complete sequencing and characterization of 21,243 full-length human cDNAs.
14649320 2003 Differential segregation of beta+ IVS-I-110 (G --> A), A(gamma) -117 (G-->A), and G(gamma) -158 (C --> T) mutations in members of an Albanian family.
12543931 2002 Toward a human blood serum proteome: analysis by multidimensional separation coupled with mass spectrometry.
12488461 2002 The human plasma proteome: history, character, and diagnostic prospects.
12477932 2002 Generation and initial analysis of more than 15,000 full-length human and mouse cDNA sequences.
11827978 2002 Assembly of human hemoglobin (Hb) beta- and gamma-globin chains expressed in a cell-free system with alpha-globin chains to form Hb A and Hb F.
11791877 2001 A new Ggamma chain variant: Hb F-Coignieres [gamma75(E19)Ile-->Val].
11514664 2001 Oligomerization and ligand binding in a homotetrameric hemoglobin: two high-resolution crystal structures of hemoglobin Bart's (gamma(4)), a marker for alpha-thalassemia.
11172039 2001 Mechanism for fetal globin gene expression: role of the soluble guanylate cyclase-cGMP-dependent protein kinase pathway.
11132233 Genetic factors affecting clinical severity in beta-thalassemia syndromes.
10722116 2000 Characterization by DNA sequencing of Hb F-Columbus-GA [Ggamma94(FG1)Asp-->Asn] observed in Sardinian newborn.
10722115 2000 Two new Ggamma chain variants: Hb F-clamart [gamma17(A14)Lys-->Asn] and Hb F-Ouled Rabah [gamma19(B1)Asn-->Lys].
10722114 2000 A new, electrophoretically silent, fetal hemoglobin variant: Hb F-Calabria [Ggamma118(GH1)Phe-->Leu].
10335983 1999 A novel C-->A transversion within the distal CCAAT motif of the Ggamma-globin gene in the Algerian Ggammabeta+-hereditary persistence of fetal hemoglobin.
8718701 1995 The G gamma T chain (G gamma 75 Thr; 136 Gly) in Hb F-Charlotte is the product of an A gamma gene with a limited gene conversion and that in Hb F-Waynesboro of a mutated G gamma gene.
8718700 1995 Hb F-Veleta or alpha 2 G gamma(2)40(C6)Arg-->Gly.
8566966 1996 HbF-Lesvos: an HbF variant due to a novel G gamma mutation (:G gamma 75 ATA-->ACA) detected in a Greek family.
8144355 1993 Hb F-Saskatoon or alpha 2G gamma (2)21(B3)Glu-->Lys observed in a North American Indian newborn.
7741137 1995 Hemoglobin F-Cincinnati, alpha 2G gamma 2 41(C7) Phe-->Ser in a newborn with cyanosis.
7713741 1994 Hb F-Macedonia-II [G gamma 104(G6)Lys-->Asn]: a new gamma chain variant.
7687855 1993 The molecular basis of HPFH in a British family identified by heteroduplex formation.
7687241 1993 Hb F-Sacromonte or alpha 2G gamma (2)59(E3)Lys-->Gln observed in a Spanish newborn and his mother.
7558873 Two fetal hemoglobin variants affecting the same residue: Hb F-Emirates [G gamma 59(E3)Lys-->Glu] and Hb F-Sacromonte [G gamma 59(E3)Lys-->Gln].
7438203 1980 Human fetal G gamma- and A gamma-globin genes: complete nucleotide sequences suggest that DNA can be exchanged between these duplicated genes.
7332928 1981 A history of the human fetal globin gene duplication.
7250702 1980 Nucleotide sequence of human G gamma globin messenger RNA.
7162987 1982 Duplication followed by deletion accounts for the structure of an Indian deletion beta (0)-thalassemia gene.
7151176 1982 A single-base change at a splice site in a beta 0-thalassemic gene causes abnormal RNA splicing.
6985481 1981 Nonsense and frameshift mutations in beta 0-thalassemia detected in cloned beta-globin genes.
6985477 1980 The structure and evolution of the human beta-globin gene family.
6985475 1980 Nonsense mutation as a cause of beta 0 thalassemia.
6895866 1981 Beta + thalassemia: aberrant splicing results from a single point mutation in an intron.
6814491 1982 Hemoglobin F Lód? (G gamma I 44 Ser replaced by Arg). A newly identified variant from an American infant of Polish descent.
6714226 1984 Molecular characterization of seven beta-thalassemia mutations in Asian Indians.
6701091 1984 Alternative sites of transcription initiation upstream of the canonical cap site in human gamma-globin and beta-globin genes.
6652684 1983 Unexpected relationships between four large deletions in the human beta-globin gene cluster.
6457059 1981 beta zero thalassemia in Sardinia is caused by a nonsense mutation.
6330670 1984 Human fetal globin DNA sequences suggest novel conversion event.
6327288 1984 The beta-globin gene in Sardinian delta beta 0-thalassemia carries a C----T nonsense mutation at codon 39.
6324786 1984 A fusion gene in man: DNA sequence analysis of the abnormal globin gene of hemoglobin Miyada.
6303333 1983 A weak upstream promoter gives rise to long human beta-globin RNA molecules.
6297279 1982 The structure and expression of the haemoglobin genes.
6292840 1982 mRNA-deficient beta o-thalassemia results from a single nucleotide deletion.
6292831 1982 Epsilon globin gene transcripts originating upstream of the mRNA cap site in K562 cells and normal human embryos.
6280057 1982 Linkage of beta-thalassaemia mutations and beta-globin gene polymorphisms with DNA polymorphisms in human beta-globin gene cluster.
6272205 1981 Structure and expression of a cloned beta o thalassaemic globin gene.
6270663 1981 A nucleotide change at a splice junction in the human beta-globin gene is associated with beta 0-thalassemia.
6264391 1981 An intron nucleotide sequence variant in a cloned beta +-thalassaemia globin gene.
6210198 1984 A molecular study of a family with Greek hereditary persistence of fetal hemoglobin and beta-thalassemia.
6208955 1984 Concordance of a point mutation 5' to the G gamma globin gene with G gamma beta +. Hereditary persistence of fetal hemoglobin in the black population.
6206897 1984 Hb F-La Grange or alpha 2 gamma 2 101(G3)Glu----Lys; 75Ile; 136Gly: a high oxygen affinity fetal hemoglobin variant observed in a Caucasian newborn.
6194897 1983 Multiple origins of transcription in the 4.5 Kb upstream of the epsilon-globin gene.
6194893 1983 Human beta-globin promoter and coding sequences transcribed by RNA polymerase III.
6192110 1983 Hb F-Kennestone or alpha 2G gamma 2 (EF1)77 His leads to Arg observed in a Caucasian baby.
6186636 1982 Hb F-Columbus-Ga or alpha 2 G gamma 2 94(FGl) Asp replaced by Asn.
6186635 1982 Hemoglobin F-Caltech: alpha 2 G gamma 2 120Lys replaced by Gln.
6186522 1982 Hb F Kingston (G gamma 55 [D6] Met leads to Arg).
6184621 1982 The deletion in a type of delta 0-beta 0-thalassaemia begins in an inverted AluI repeat.
6172403 1981 Hb F-Meinohama or alpha 2 gamma 2 (5 Glu replaced by Gly; 75 Ile; 136 Gly).
6165992 1981 beta-Thalassemia present in cis to a new beta-chain structural variant, Hb Vicksburg [beta 75 (E19)Leu leads to 0].
6158500 1980 A new abnormal fetal hemoglobin, Hb FM-Osaka (alpha 2 gamma 2 63His replaced by Tyr).
6155216 1980 Molecular cloning and characterization of the human beta-like globin gene cluster.
6095301 1984 Identification of a retrovirus-like repetitive element in human DNA.
6091051 1984 Two novel arrangements of the human fetal globin genes: G gamma-G gamma and A gamma-A gamma.
6086605 1984 Base substitution at position -88 in a beta-thalassemic globin gene. Further evidence for the role of distal promoter element ACACCC.
5792729 1969 Haemoglobin F(Malta): a new foetal haemoglobin variant with a high incidence in Maltese infants.
5554303 1971 Human fetal hemoglobin F 1. Acetylation status.
4846278 1974 Haemoglobin F Port Royal (alpha2G gamma2 125 Glu leads to Ala).
4837284 1974 Haemoglobin F Malaysia: alpha 2, gamma 2 1(NA1) glycine--cysteine; 136 glycine.
4429671 1974 Haemoglobin F auckland G gamma 7 Asp leads to Asn: further evidence for multiple genes for the gamma chain.
4403130 1972 Soluble cytochrome b 5 reductase from human erythrocytes.
3879975 1985 The "beta-like-globin" gene domain in human erythroid cells.
3879973 1985 Cryptic branch point activation allows accurate in vitro splicing of human beta-globin intron mutants.
3857622 1985 mRNA precursor splicing in vivo: sequence requirements determined by deletion analysis of an intervening sequence.
3455755 1986 Hemoglobin Long Island is caused by a single mutation (adenine to cytosine) resulting in a failure to cleave amino-terminal methionine.
3382401 1988 Beta-thalassemia due to a T----A mutation within the ATA box.
3267215 1988 Direct sequencing of enzymatically amplified human genomic DNA.
3120456 1987 Neonatal screening and mass-spectrometric analysis of hemoglobin variants in Japan.
2933810 1985 The 3' splice site of pre-messenger RNA is recognized by a small nuclear ribonucleoprotein.
2649166 1989 A review of the molecular genetics of the human alpha-globin gene cluster.
2581919 1985 Hb F-Tokyo or alpha 2G gamma 2 34(B16)Val----Ile, a silent gamma chain variant detected by reverse phase high performance liquid chromatography.
2581851 1985 Cloning specific complete polyadenylylated 3'-terminal cDNA segments.
2579547 1985 -G gamma A gamma-Thalassemia and gamma-chain variants in Chinese newborn babies.
2578620 1985 A point mutation in the A gamma-globin gene promoter in Greek hereditary persistence of fetal haemoglobin.
2578619 1985 G to A substitution in the distal CCAAT box of the A gamma-globin gene in Greek hereditary persistence of fetal haemoglobin.
2483933 1989 Hb F-M-Osaka or alpha 2G gamma 2(63)(E7)His----Tyr in a Caucasian male infant.
2470017 1989 Mutant fetal hemoglobin causing cyanosis in a newborn.
2459083 1988 Hb F-Austell or alpha 2G gamma (2)40(C6)Arg----Lys.
2459082 1988 Hb F-Granada or alpha 2G gamma (2)22(B4)Asp----Val: a new human fetal hemoglobin variant.
2442123 1987 Hb F-Clarke or alpha 2G gamma 2(65)(E9)Lys----Asn.
2442122 1987 Hb F-Oakland or alpha 2G gamma I2(26)(B8)Glu----Lys.
2441598 1987 The Greek A gamma beta+-HPFH observed in a large black family.
2435680 1986 Hb F-Albaicin or G gamma 8(A5)Lys----Glu or Gln.
2420748 1986 Hb F-Urumqi G gamma I22(B4)Asp----Gly: a new fetal hemoglobin variant found in a Uygur baby.
2416635 1986 Short gene conversions in the human fetal globin gene region: a by-product of chromosome pairing during meiosis?
2413469 1985 Sequences of G gamma, A gamma, and beta genes of the Greek (A gamma) HPFH mutant: evidence for a distal CCAAT box mutation in the A gamma gene.
1726095 1991 Hb F-Cosenza or G gamma 25(B7)Gly----Glu: a new fast-moving fetal hemoglobin variant.
1714434 1990 Hb F-Charlotte, an A gamma variant with a threonine residue in position gamma 75 and a glycine residue in position gamma 136.
1706691 1990 Hb F-Catalonia or alpha 2G gamma(2)15(A12)Trp----Arg.
1703139 1990 Hb F-Onoda or alpha 2G gamma 2(146)(HC3)His----Tyr, a newly discovered fetal hemoglobin variant in a Japanese newborn.
1703138 1990 Hb F-Brooklyn or alpha 2G gamma 2(66)(E10)Lys----Gln.
1698280 1990 A novel C-T transition within the distal CCAAT motif of the G gamma-globin gene in the Japanese HPFH: implication of factor binding in elevated fetal globin expression.
1127124 1975 A new cause of haemolytic anaemia in the newborn. A description of an unstable fetal haemoglobin: F Poole, alpha2-G-gamma2 130 trptophan yeilds glycine.
881729 1977 Structure of human foetal deoxyhaemoglobin.
873928 1977 Human beta-globin messenger RNA. I. Nucleotide sequences derived from complementary RNA.
836882 1977 Haemoglobin F Melbourne Ggamma 16 Gly leads to Arg and haemoglobin F carlton Ggamma 121 Glu leads to Lys. Further evidence for varied activity of gamma-chain genes.
822353 1976 3' non-coding region sequences in eukaryotic messenger RNA.
88735 1979 beta 0 thalassemia, a nonsense mutation in man.