Open Access

Compound heterozygous hemophilia A in a female patient and the identification of a novel missense mutation, p.Met1093Ile

  • Authors:
    • Shu-Kai Qiao
    • Han-Yun Ren
    • Jin-Hai Ren
    • Xiao-Nan Guo
  • View Affiliations

  • Published online on: December 4, 2013     https://doi.org/10.3892/mmr.2013.1841
  • Pages: 466-470
  • Copyright: © Qiao et al. This is an open access article distributed under the terms of Creative Commons Attribution License [CC BY_NC 3.0].

Metrics: Total Views: 0 (Spandidos Publications: | PMC Statistics: )
Total PDF Downloads: 0 (Spandidos Publications: | PMC Statistics: )


Abstract

Hemophilia A (HA) in females is rare. Female HA cases are often misdiagnosed as acquired HA (AHA) or as von Willebrand disease type 2N (vWD-2N). Here, we report the case of a 37-year-old female HA patient with a moderate factor VIII (FVIII) deficiency. The patient had no personal or family history of bleeding disorders, but presented with heavy uterine bleeding following surgery to remove an intrauterine device. IgG inhibitory antibodies against FVIII were undetected. A compound heterozygote mutation of the FVIII gene (F8) was found in this patient. The p.Val502Asp mutation, which has been reported previously, affects A2 domain function. A novel missense point mutation, p.Met1093Ile, was identified in the B domain. The compound heterozygote mutations in F8, p.Val502Asp and p.Met1093Ile, caused HA in this female patient, with a moderate phenotype.

Introduction

Hemophilia A (HA) is an X-linked recessive congenital coagulation disorder caused by a factor VIII (FVIII) deficiency, which results from mutations in the FVIII gene (F8). HA typically occurs in males with an incidence of ~1 in 5000 (1). Female HA patients have rarely been reported, although they may carry a defective allele. Human F8 maps to the long arm of the Xq28 region of the X chromosome and consists of 26 exons and 25 introns. The protein product of F8 possesses no enzyme activity. The 19 amino acid signal peptide at the N-terminus, encoded by an open reading frame (ORF), leads to the passage of FVIII through hepatocytes to blood vessels (2). The matured FVIII protein is composed of 2332 amino acids and comprises three homologous A domains, two homologous C domains and a single B domain. These domains, arranged as A1-A2-B-A3-C1-C2 from the N- to the C-terminus, are important for FVIII function. FVIII synthesized in hepatocytes is secreted into the plasma in the form of an inactive pro-cofactor (3). FVIII, an essential cofactor for coagulation factor IX, readily binds to von Willebrand factor (vWF), forming a tight non-covalent complex that protects against degradation. Furthermore, FVIII may also interact with a number of proteins, such as thrombin and factor X. These interactions are indispensable for effective coagulation. Once FVIII is cleaved by thrombin, activated FVIII dissociates from vWF and participates in the coagulation cascade (4).

Genetic abnormalities in F8 may result in qualitative or quantitative defects of the FVIII protein. The most common F8 abnormality to cause HA is an inversion of intron 1 or 22 (5,6). The remaining HA cases are caused by numerous point mutations spread throughout the gene, including missense, nonsense, splice site, frameshift mutations and gross deletions (7,8). To date, >1400 F8 mutations within the FVIII coding and non-coding regions have been identified in the Haemophilia A Mutation, Search, Test and Resource Site (HAMSTeRS) database (http://hadb.org.uk/).

In this study, we report the case of a female HA patient with F8 compound heterozygote mutations. Diagnosis and differential diagnosis were complex. Furthermore, F8 compound heterozygote mutations (c.1505T>A, p.Val502Asp and c.3279G>A, p.Met1093Ile) were identified using multiplex PCR and DNA sequencing.

Case report

Patient history

A 37-year-old female patient presented with an 8-month history of severe uterine abnormal bleeding following surgery for the removal of an intrauterine device. After a short time, the patient developed profound anemia (hemoglobin level of 58 g/l). Prior to being admitted to our hospital, the patient had received a blood transfusion (1200 ml) for hemorrhagic anemia in the Second Hospital of Hebei Medical University. Furthermore, the patient complained of repeated skin purpura since childhood. The patient had no other history of bleeding, such as nosebleeds, gingival bleeding, hematemesis or melena. There was no personal or family history of bleeding disorders. The patient denied any intake of medicines or herbs. The biochemical and hematological data of the patient are shown in Table I.

Table I

Initial biochemistry and hematology results.

Table I

Initial biochemistry and hematology results.

VariableValueReference range
Whole blood
 White blood cell 5.8×109/l type4/xref>–10)x109/l
 Hemoglobin92 g/l110–155 g/l
 Platelet 216×109/l (100–300)×109/l
Coagulation panel
 PT14.6 sec12–16 sec
 INR1.120.8–1.2
 APTT46.5 sec24–37sec
 APTT-R1.620.8–1.2
 Fib242 mg/dl200–400 mg/dl
 BT11 min4.8–9 min
 FVIII:C4.7%50–150%
 vWF-Ag128%60–150%
 LA29.5 sec27–41 sec
 RIPA (1.2 mg/ml)91%87–102%
 Factor VIII antibodyNegativeNegative

[i] PT, prothrombin time; INR, international normalized ratio; APTT: activated partial thromboplastin time; Fib, fibrinogen; BT, bleeding time; vWF-Ag, von Willebrand factor antigen; LA, lupus anticoagulant; RIPA, ristocetin induced platelet agglutination.

White blood cell and platelet levels were within the normal ranges. Hemoglobin was only marginally reduced (92 g/l), due to the blood transfusion. The prothrombin time (PT) and international normalized ratio (INR) were normal, but the activated partial thromboplastin time (APTT) and bleeding time (BT) were noticeably prolonged, which may be corrected easily by a plasma transfusion. Plasma FVIII levels were significantly decreased (4.7%). vWF antigen levels were within the normal range (128%). Autoimmune markers, such as the antinuclear, anticardiolipin, antidouble stranded DNA and extractable nuclear antigen (ENA) polypeptide antibodies were all negative. Other coagulation tests were also normal, including platelet count and function, and fibrinogen levels.

Diagnosis and differential diagnosis

Based on the clinical manifestations and laboratory tests, the following diagnoses were considered, in order of decreasing probability: i) Acquired HA (AHA); ii) von Willebrand disease type 2N (vWD-Type 2N); and iii) HA. There is a certain degree of overlap in the clinical manifestations and laboratory results among these three disorders. Although female HA is extremely rare, it could not be ruled out as a possibility. The key points of diagnosis and differential diagnosis for these three diseases are discussed in the following paragraphs.

AHA is an autoimmune disorder caused by autoantibodies against FVIII, neutralizing its coagulation functions and resulting in severe, often life-threatening bleeding. It is characterized by severe, spontaneous hemorrhaging at sites, such as the skin, muscle and soft tissues, or by excessive bleeding during surgery. Hemarthrosis, the hallmark of severe congenital HA, seldom occurs in AHA patients (9). AHA may be associated with several clinical conditions, including pregnancy, autoimmune diseases, malignancies, infections or drugs. Approximately 50% of patients are idiopathic with no known underlying disease association (10). If a patient presents with spontaneous hemorrhaging, then previous personal or family history of bleeding must be ruled out. Once laboratory results reveal the isolated prolongation of APTT and reduced FVIII levels, which fail to normalize following a normal plasma transfusion, AHA should be suspected. Following confirmation that FVIII antibodies are absent and that FVIII levels may be improved by transfusing normal plasma, a diagnosis of AHA was definitively ruled out.

vWD is the most common inherited bleeding disorder and is caused by deficiency or dysfunction of vWF. vWD is divided into three types: Type 1 (partial quantitative deficiency); Type 2, with four subtypes 2A, 2B, 2M and 2N (qualitative deficiency); and Type 3 (complete quantitative deficiency) (11). Type 2N vWD show a marked decrease in the vWF binding affinity for FVIII. Its clinical manifestations are similar to that of mild HA: FVIII levels are decreased, but vWF antigen (vWF:Ag) levels are within the normal range (12). These patients are usually misdiagnosed as HA. When the laboratory results were returned, it was observed that the vWF binding affinity for FVIII and the ristocetin-induced platelet agglutination (RIPA) were normal in our patient. Therefore, a diagnosis of vWD-Type 2N was ruled out. Thus, a diagnosis of HA was considered for the patient. The differential diagnoses of HA, VWD-Type 2N and AHA are outlined in Table II.

Table II

Differential diagnosis of HA, vWD-Type 2N and AHA.

Table II

Differential diagnosis of HA, vWD-Type 2N and AHA.

VariableHAvWD-Type 2NAHA
BTNormalNormal or (↑)Normal
APTT
FVIII:C
vWF-AgNormal(↓) or NormalNormal
FVIII inhibitorNegativeNegativePositive
vWF-FVIII binding affinityNormalNormal
vWF:RcofNormal(↓) or NormalNormal

[i] HA: hemophilia A; AHA: Acquired HA; vWD, von Willebrand disease; FVIII:C, coagulation factor VIII activity; vWF, von Willebrand factor; vWF:Ag, vWF antigen; vWF:RCof, vWF ristocetin cofactor activity.

Mutational screening

In order to confirm the cause of HA in the patient, a mutational screening of F8 was performed. Genomic DNA was obtained from EDTA-anticoagulated blood from the patient. Inversions in introns 1 and 22 were first screened using long-distance PCR (13). All exons and their flanking regions of F8 were amplified by PCR using specific primers, as described previously (14). PCR products were purified and sequenced.

DNA sequencing

Introns 1 and 22 were not inverted. A previously reported mutation (15) was detected (exon 10, c.1505T>A, p.Val502Asp), and a novel unreported missense point mutation (exon 14, c.3279G>A, p.Met1093Ile) (Fig. 1).

Molecular modeling

Mutated FVIII proteins were modeled using the crystal structure of activated recombinant FVIII (16,17). Structural images were generated using the Swiss-Pdb Viewer (Swiss Institute of Bioinformatics, Geneva, Switzerland) (18) (Fig. 2).

Conserved domains analysis

A conserved domains analysis was conducted for p.Val502 and p.Met1093 by using the Multiple Alignment Tool (http://www.ncbi.nlm.nih.gov/tools/cobalt/cobalt.cgi?link_loc=BlastHomeLink). It was observed that p.Val502 of the A2 domains in F8 is highly conserved among mammals (Table III). By contrast, p.Met1093 in the B domain shares little amino acid homology, indicating that it is not conserved among different species.

Table III

Conserved domains analysis in F8 for p.V483(502).

Table III

Conserved domains analysis in F8 for p.V483(502).

SpeciesDomainNucleotide number
Hs PLLYGEVGDTLLIIFKNQASRPYNIYPHGITDVRPLYSRRLPKGVKHLKDFPILGEIFKYKWTVTVEDGPT541
Mm PLLYGEVGDTLLIIFKNQASRPYNIYPHGITDVSPLHARRLPRGIKHVKDLPIHPGEIFKYKWTVTVEDGPT541
Rn PLLYGEVGDSLLIVFKNRASRAYNIHPHGIRDVGAVHAGRLPRGVKHVKDLPIRPGETFKYRWTLTAEDGPA529
Cf PLLYGEVGDTLLIIFKKQASRPYNIYPHGINYVTPLHTGRLPKGVKHLKDMPILPGEIFKYKWTVTVEDGPT535
Bt PLLYGEVGDTLLIIFKNQASRPYNIYPHGITDVSPLHSGRFPKGVKHLKDMPILGEVFKYKWTVTVEDGPT536
Oc PLLYGEVGDTLLIIFKNQASRPYNIYPHGITDVSPLHSGRLSKGMKHLKDLPILPGEIFYKWKVTVEDGPT537
Gg PVLKGEVGDQFKIVFRNLASRPYNIYPHGLTSVNPYHAMKPSQGKKDVKDIPAPGQSFTYRWSITTEDGPT529
Oa PLLYGEVGDTLLIIFKNQASRPYNIYPHGITDVSPLHSGRFPKGVKHLKDMPILPGEVFKYKWTVTVEDGPT536
Ss PLLYGEVGDTLLIIFKNKASRPYNIYPHGITDVSALHPGRLLKGWKHLKDMPILPGETFKYKWTVTVEDGPT541
Tr PLLKGKVGDQIHIMLKNTASRPFNIYPNGLSSIRPMKRSKNAS-EKDLRTMGVGPNETFGYMWELTANDRPL546
Sh PLLYGEVGDMLLITFKNLASRPYNIYPHGLTSVSPLHSGRLPKGVKDVKDMPIMPGQTFKYKWEVTMEDGPT541
La PLLYGEVGDTLLIIFKNQASRPYNIYPHGITNVSPLHSGRLSKGVKHLKDLQIMPGEIFKYKWTVTLEDGPT542
Dr PELRGEVGDKFQIVFKNMASRPFNIYPNGLTSVQPLKTTNKDK-QVDLRSLAVPPGEIMTYLWKLTAEGDPT530

[i] V483(502) is highly conserved among mammalians (in bold). Hs, Homo sapiens; Mm, Mus musculus; Rn, Rattus norvegicus; Cf, Canis lupus familiaris; Bt, Bos taurus; Oc, Oryctolagus cuniculus; Gg, Gallus gallus; Oa, Ovis aries; Ss, Sus scrofa; Tr, Takifugu rubripes; Sh, Sarcophilus harrisii; La, Loxodonta africana; Dr, Danio rerio.

Discussion

Due to the X-linked recessive mode of inheritance, HA usually affects males, and females usually are carriers who may pass the disease on to their progeny (19). Thus, female HA cases are rarely observed. However, in certain cases, there are a variety of potential genetic mechanisms leading to HA in females: i) Non-random inactivation of the normal X-chromosome in a female HA carriers (the most common cause of female HA (20,21); ii) homozygous F8 mutations (mostly reported in India where consanguineous marriages are more common) (22,23); iii) compound heterozygous mutations affecting both F8 alleles (21); and iv) X-chromosome monosomy or gross structural defects, such as a deletion or translocation (2426).

Disease severity in HA patients is classified according to residual plasma FVIII activity (FVIII:C): severe (<1%), moderate (1–5%) and mild (5–35%) (27). In the severe phenotype, the most prevalent mutations are inversions of introns 1 or 22, accounting for 5% and 40–50% of patients, respectively (5,28). Moderate or mild HA are usually caused by missense mutations (29).

In this study, we presented the case of a female HA patient with a moderately clinical phenotype (FVIII: C=4.8%) resulting from F8 compound heterozygous mutations. The p.Val502Asp mutation located in A2 domains was first reported to be associated with mild HA by Fernández-López et al (15) in 2005. As the original amino acid Val502 in F8 is highly conserved among all known mammals, it was predicted that Val502 is involved in an A2-specific functional role. The non-polar, hydrophobic amino acid Val is replaced by the polar and acidic amino acid Asp, resulting in altered stability and protein folding. The p.Met1093Ile mutation is located in the B domain of F8, which is encoded by exon 14 (amino acids 741–1648). Contrary to the A and C domains, there are no available molecular models or crystal structures that elucidate the detailed structural information of the B domain. The FVIII B domain shares little sequence homology with other known mammalian species. Despite the fact that the B domain is not directly required for FVIII coagulation activity, it has been shown to exhibit a major role in the intracellular interactions that regulate quality control and secretion, as well as potential regulatory roles within plasma during activation, platelet binding, inactivation and clearance (30). Therefore, the p.Met1093Ile mutation in the B domain also affects FVIII coagulation activity. Furthermore, missense mutations within the F8 B domain have often been reported in HA patients (31,32). p.Met1093Ile is a novel missense mutation unreported in the HAMSTeRS database. The mutation was submitted to the HAMSTeRS database and was accepted (unpublished). It was estimated that the compound heterozygous mutations (p.Val502Asp and p.Met1093Ile) are causative gene defects, which resulted in a moderate HA phenotype in this female patient.

In conclusion, female HA patients, particularly those without a personal or family history of bleeding disorders, are often misdiagnosed as AHA or vWD-type 2N. A diagnosis of HA should be made in a female patient when isolated APTT is prolonged, FVIII binding capacity for vWF is normal, FVIII levels are decreased and FVIII auto-antibodies are absent. Genetic analysis of F8 using multiplex PCR and DNA sequencing is an essential tool in elucidating the nature of the various molecular mechanisms resulting in HA in females.

Acknowledgements

The authors are grateful to Dr Ye-ling Lu (Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China) for his technical assistance in mutational analysis and to Professor Jing-yu Zhang (The Second Hospital of Hebei Medical University, Shijiazhuang, Hebei, China) for measuring the vWF binding affinity for FVIII.

References

1 

Klinge J, Ananyeva NM, Hauser CA and Saenko EL: Hemophilia A - from basic science to clinical practice. Semin Thromb Hemost. 28:309–322. 2002. View Article : Google Scholar : PubMed/NCBI

2 

Saenko EL, Ananyeva NM, Tuddenham EG and Kemball-Cook G: Factor VIII - novel insights into form and function. Br J Haematol. 119:323–331. 2002. View Article : Google Scholar : PubMed/NCBI

3 

Lenting PJ, van Mourik JA and Mertens K: The life cycle of coagulation factor VIII in view of its structure and function. Blood. 92:3983–3996. 1998.PubMed/NCBI

4 

Lenting PJ, Pegon JN, Christophe OD and Denis CV: Factor VIII and von Willebrand factor - too sweet for their own good. Haemophilia. 16:194–199. 2010. View Article : Google Scholar : PubMed/NCBI

5 

Bagnall RD, Waseem N, Green PM and Giannelli F: Recurrent inversion breaking inversion intron 1 of the factor VIII gene is a frequent cause of severe hemophilia A. Blood. 99:168–174. 2002. View Article : Google Scholar : PubMed/NCBI

6 

Oldenburg J, Brackmann HH, Hanfland P and Schwaab R: Molecular genetics in haemophilia A. Vox Sang. 78:33–38. 2000.

7 

Castaldo G, D’Argenio V, Nardiello P, et al: Haemophilia A: molecular insights. Clin Chem Lab Med. 45:450–461. 2007. View Article : Google Scholar : PubMed/NCBI

8 

Oldenburg J: Mutation profiling in haemophilia A. Thromb Haemost. 85:577–579. 2001.PubMed/NCBI

9 

Shetty S, Bhave M and Ghosh K: Acquired hemophilia A: diagnosis, aetiology, clinical spectrum and treatment options. Autoimmun Rev. 10:311–316. 2011. View Article : Google Scholar : PubMed/NCBI

10 

Franchini M, Targher G, Montagnana M and Lippi G: Laboratory, clinical and therapeutic aspects of acquired hemophilia A. Clin Chim Acta. 395:14–18. 2008. View Article : Google Scholar : PubMed/NCBI

11 

Sadler JE, Budde U, Eikenboom JC, et al: Update on the pathophysiology and classification of von Willebrand disease: A report of the Subcommittee on von Willebrand Factor. J Thromb Haemost. 4:2103–2114. 2006. View Article : Google Scholar : PubMed/NCBI

12 

Nichols WL, Rick ME, Ortel TL, et al: Clinical and laboratory diagnosis of von Willebrand disease: a synopsis of the 2008 NHLBI/NIH guidelines. Am J Hematol. 84:366–370. 2009. View Article : Google Scholar : PubMed/NCBI

13 

Keeney S, Mitchell M and Goodeve A; the UK Haemophilia Center Doctors’ Organisation Harmophilia Genetics Laboratory Network. The molecular analysis of haemophilia A: a guideline from the UK haemophilia centre doctors’ organization haemophilia genetics laboratory network. Haemophilia. 11:387–397. 2005.

14 

Boekhorst J, Verbruggen B, Lavergne JM, et al: Thirteen novel mutations in the factor VIII gene in the Nijmegen haemophilia A patient population. Br J Haematol. 131:109–117. 2005. View Article : Google Scholar : PubMed/NCBI

15 

Fernández-López O, García-Lozano JR, Núñez-Vázquez R, Pérez-Garrido R and Núñez-Roldán A: The spectrum of mutations in Southern Spanish patients with hemophilia A and identification of 28 novel mutations. Haematologica. 90:707–710. 2005.PubMed/NCBI

16 

Shen BW, Spiegel PC, Chang CH, et al: The tertiary structure and domain organization of coagulation factor VIII. Blood. 111:1240–1247. 2008. View Article : Google Scholar : PubMed/NCBI

17 

Kopp J and Schwede T: The SWISS-MODEL repository of annotated 3-dimensional protein structure homology models. Nucleic Acids Res. 32:D230–D234. 2004. View Article : Google Scholar : PubMed/NCBI

18 

Guex N and Peitsch MC: SWISS-MODEL and the Swiss-PdbViewer: an environment for comparative protein modeling. Electrophoresis. 18:2714–2723. 1997. View Article : Google Scholar : PubMed/NCBI

19 

Pavlova A, Brondke H, Müsebeck J, et al: Molecular mechanisms underlying hemophilia A phenotype in seven females. J Thromb Haemost. 7:976–982. 2009. View Article : Google Scholar : PubMed/NCBI

20 

Favier R, Lavergne JM, Costa JM, et al: Unbalanced X-chromosome inactivation with a novel FVIII gene mutation resulting in severe hemophilia A in a female. Blood. 96:4373–4375. 2000.PubMed/NCBI

21 

Knobe KE, Sjörin E, Soller MJ, Liljebjörn H and Ljung RC: Female haemophilia A caused by skewed X inactivation. Haemophilia. 14:846–848. 2008. View Article : Google Scholar : PubMed/NCBI

22 

Nair PS, Shetty S and Ghosh K: A homozygous female hemophilia A. Indian J Hum Genet. 18:134–136. 2012. View Article : Google Scholar : PubMed/NCBI

23 

Renault NK, Dyack S, Dobson MJ, et al: Heritable skewed X-chromosome inactivation leads to haemophilia A expression in heterozygous females. Eur J Hum Genet. 15:628–637. 2007. View Article : Google Scholar : PubMed/NCBI

24 

Cai XH, Wang XF, Dai J, et al: Female hemophilia A heterozygous for a de novo frameshift and a novel missense mutation of factor VIII. J Thromb Haemost. 4:1969–1974. 2006. View Article : Google Scholar : PubMed/NCBI

25 

Martín-Salces M, Venceslá A, Alvárez-Román MT, et al: Clinical and genetic findings in five female patients with haemophilia A: Identification of a novel missense mutation, p.Phe2127Ser. Thromb Haemost. 104:718–723. 2010.PubMed/NCBI

26 

Venceslá A, Fuentes-Prior P, Baena M, et al: Severe haemophilia A in a female resulting from an inherited gross deletion and a de novo codon deletion in the F8 gene. Haemophilia. 14:1094–1098. 2008.PubMed/NCBI

27 

Jayandharan G, Shaji RV, Baidya S, et al: Identification of factor VIII gene mutation in 101 patients with haemophilia A: mutation analysis by inversion screening and multiplex PCR and CSGE and molecular modeling of 10 novel missense substitutions. Haemophilia. 11:481–491. 2005. View Article : Google Scholar : PubMed/NCBI

28 

Lakich D, Kazazian HH Jr, Antonarakis SE and Gitschier J: Inversions disrupting the factor VIII gene are a common cause for severe haemophilia A. Nat Genet. 5:236–241. 1993. View Article : Google Scholar : PubMed/NCBI

29 

Jacquemin M, De Maeyer M, D’Oiron R, et al: Molecular mechanisms of mild and moderate hemophilia A. J Thromb Haemost. 1:456–463. 2003. View Article : Google Scholar

30 

Pipe SW: Functional roles of the factor VIII B domain. Haemophilia. 15:1187–1196. 2009. View Article : Google Scholar : PubMed/NCBI

31 

Green PM, Bagnall RD, Waseem NH and Giannelli F: Haemophilia A mutations in the UK: results of screening one-third of the population. Br J Haematol. 143:115–128. 2008. View Article : Google Scholar : PubMed/NCBI

32 

Repessé Y, Slaoui M, Ferrandiz D, et al: Factor VIII (FVIII) gene mutations in 120 patients with hemophilia A: detection of 26 novel mutations and correlation with FVIII inhibitor development. J Thromb Haemost. 5:1469–1476. 2007.PubMed/NCBI

Related Articles

Journal Cover

2014-February
Volume 9 Issue 2

Print ISSN: 1791-2997
Online ISSN:1791-3004

Sign up for eToc alerts

Recommend to Library

Copy and paste a formatted citation
x
Spandidos Publications style
Qiao S, Ren H, Ren J and Guo X: Compound heterozygous hemophilia A in a female patient and the identification of a novel missense mutation, p.Met1093Ile. Mol Med Rep 9: 466-470, 2014
APA
Qiao, S., Ren, H., Ren, J., & Guo, X. (2014). Compound heterozygous hemophilia A in a female patient and the identification of a novel missense mutation, p.Met1093Ile. Molecular Medicine Reports, 9, 466-470. https://doi.org/10.3892/mmr.2013.1841
MLA
Qiao, S., Ren, H., Ren, J., Guo, X."Compound heterozygous hemophilia A in a female patient and the identification of a novel missense mutation, p.Met1093Ile". Molecular Medicine Reports 9.2 (2014): 466-470.
Chicago
Qiao, S., Ren, H., Ren, J., Guo, X."Compound heterozygous hemophilia A in a female patient and the identification of a novel missense mutation, p.Met1093Ile". Molecular Medicine Reports 9, no. 2 (2014): 466-470. https://doi.org/10.3892/mmr.2013.1841