Identification and Characterization of Primary Factor VII Gene Mutations and Incidentally Detected Secondary MTHFR and ITGA2 Genetic Variants in a Factor VII Deficiency Cohort: A Single-Hemophilia Center Study

Factor VII (F7) deficiency is a rare, autosomal recessive bleeding disorder affecting approximately 1:300,000-500,000 individuals and is caused by mutations in the F7 gene. The clinical presentation varies widely, from mucocutaneous to life-threatening bleeding. Factor levels do not always correlate with symptom severity.

Diagnosis relies on coagulation tests and treatment options range from local hemostatic agents and hormonal therapy in women, to F7 replacement.

Historically, F7 deficiency has been more prevalent in regions with higher rates of consanguineous marriage.

This study examines a cohort of 25 patients residing in Eastern North Carolina, with a concentrated distribution across several counties in the region. While consanguinity was not explicitly confirmed, the geographic clustering of patients may suggest potential familial relationships.

Our cohort included 25 patients: 13 (52%) female, 12 (48%) male; 18 (72%) Black/African American, 6 (24%) White, and 1 (4%) from ‘Other’ race. The mean age at diagnosis was 38 years for adults (>18 years) and 10 years for children (<18 years).

23 patients (92%) had mild deficiency, and 2 patients had severe deficiency.

Patients who required in-patient management were characterized under the major bleeding category and interventions included transfusions with RBCs, FFP, & recombinant F7a (Novo7).

Both patients with severe deficiency (<1% factor level) were diagnosed in adulthood, and presented with muscular hematomas, and uncontrolled menorrhagia.

Patients with mild deficiency (Levels 11-48%, median 29%) exhibited a wide range of clinical presentations. The majority (65%) experienced spontaneous bleeding, commonly manifesting as epistaxis, gum bleeding, and hematuria. Menorrhagia was seen in 90% of women. 2 patients experienced severe events (CNS bleeding and hematemesis) requiring ICU admission. 34% of the patients suffered major bleeding events.

Given this variability despite similar F7 levels, we looked at the F7 gene polymorphisms.

The Molecular Hematology Panel was completed on 12 patients (11 with mild, 1 with severe deficiency), at Hematology Advanced Diagnostics Laboratory through the American Hemostasis and Thrombosis Network.

Among the 11 patients with mild deficiency, 4 had both Likely Pathogenic Variants (LPV) and Variants of Uncertain Significance (VUS), 6 had only VUS, and 1 had only LPV in the F7 gene.

Each patient had a maximum of one LPV in the F7 gene. 5 patients carried LPV: 3 missense, 1 in-frame deletion, and 1 splice variant. These included c.691_693delTTG, c.1091G>A (in two related patients), c.805+2T>G, and c.1333G>A. Genotype (heterozygous or homozygous) did not correlate with bleeding severity.

VUS were prevalent, with up to three per patient. The most common US variants were insertion (c.-325_-324insCCTATATCCT), splice (c.64+9G>A), and missense (c.1238G>A) mutations, detected in 90%, 81%, and 54% of patients, respectively. Homozygous VUS demonstrated the highest rate of major bleeding events, suggesting a potential pathogenic role for these genetic alterations. However, due to limited sample size, definitive conclusions cannot be reached.

We also found Incidental MTHFR and ITGA2 gene mutations in 4 patients, potentially affecting platelet function and these patients primarily presented with “platelet-type” mucocutaneous bleeding.

Two patients carried Likely Benign variants in MTHFR gene mutations associated with mild-to-moderate thrombophilia, a condition that could potentially offer protection against bleeding tendencies.

The other two patients carried VUS in ITGA2 gene, which impacts α2β1 mediated platelet adhesion to collagen and is linked to platelet type bleeding disorder 9. It is possible that these variants may also reduce bleeding tendencies in some individuals.

While thrombophilia and platelet adhesion might theoretically protect against bleeding, given the occurrence of major bleeding events complicating the mucocutaneous bleeding in this small cohort, a definitive conclusion about the protective effect cannot be drawn.

The observed “protective effect” of incidental platelet function disorder mutations on bleeding tendencies associated with F7 gene mutations remains unclear.

These findings raise the possibility of a closer and more established link between F7 deficiency, bleeding disorders, and platelet dysfunction, warranting further investigation.

Isaac:Pfizer: Current equity holder in private company. Liles:Agios: Research Funding; Bristol Myers Squibb: Research Funding; Apellis: Research Funding; Incyte: Research Funding; Novartis: Research Funding; Pfizer: Research Funding.