# Underrecognized Thrombotic Risk in Klinefelter Syndrome: A Clinical Insight

**Authors:** Hrithik Dakssesh Putta Nagarajan, Mohammed Afsharhussain Hithayathulla, Tejashvi Rameshkumar, Md Ramij Biswas, Nitish Thirugnanasambandam

PMC · DOI: 10.7759/cureus.102884 · 2026-02-03

## TL;DR

This paper reports a case of deep vein thrombosis in a man with Klinefelter syndrome, emphasizing the underrecognized risk of blood clots in this condition.

## Contribution

The study highlights thrombotic risk in Klinefelter syndrome without additional thrombophilic conditions, calling for further research.

## Key findings

- A 33-year-old man with Klinefelter syndrome developed deep vein thrombosis without traditional risk factors.
- Anticoagulation therapy effectively resolved symptoms, and no other thrombophilias were identified.
- The case underscores the need for increased awareness of thrombotic risks in Klinefelter syndrome.

## Abstract

Klinefelter syndrome (KS), the most common male aneuploidy (47,XXY), is linked to hypogonadism, gynecomastia, and infertility, with an established but underrecognized association with venous thromboembolism and limited data on mechanisms in patients without additional thrombophilic conditions. We report the case of a 33-year-old South Asian male with subacute-to-chronic deep vein thrombosis (DVT) of the right leg and absent traditional thrombosis risk factors. Clinical evaluation, hormonal assays, and karyotyping confirmed KS. Extensive investigations ruled out congenital and acquired thrombophilias. The patient responded well to anticoagulation therapy, achieving symptom resolution. This case highlights the need for awareness of thrombotic risks in KS and underscores the importance of further research into the underlying mechanisms of this association.

## Linked entities

- **Diseases:** Klinefelter syndrome (MONDO:0006823)

## Full-text entities

- **Genes:** MTHFR (methylenetetrahydrofolate reductase) [NCBI Gene 4524], F5 (coagulation factor V) [NCBI Gene 2153] {aka FVL, PCCF, RPRGL1, THPH2, fV}, PROC (protein C, inactivator of coagulation factors Va and VIIIa) [NCBI Gene 5624] {aka APC, PC, PROC1, THPH3, THPH4}, SERPINC1 (serpin family C member 1) [NCBI Gene 462] {aka AT3, AT3D, ATIII, ATIII-R2, ATIII-T1, ATIII-T2}, F2 (coagulation factor II, thrombin) [NCBI Gene 2147] {aka PT, RPRGL2, THPH1}, HLA-G (major histocompatibility complex, class I, G) [NCBI Gene 3135] {aka MHC-G}, SERPINE1 (serpin family E member 1) [NCBI Gene 5054] {aka PAI, PAI-1, PAI1, PLANH1}
- **Diseases:** pain (MESH:D010146), metabolic syndrome (MESH:D024821), trauma (MESH:D014947), 47,XXY (MESH:D007713), swelling (MESH:D004487), cyanosis (MESH:D003490), diabetes mellitus (MESH:D003920), congenital and acquired thrombophilias (MESH:C540694), hypercoagulability (MESH:D019851), clubbing (MESH:D003025), gynecomastia (MESH:D006177), bleeding (MESH:D006470), obesity (MESH:D009765), lymphadenopathy (MESH:D008206), systemic lupus erythematosus (MESH:D008180), hypogonadism (MESH:D007006), azoospermia (MESH:D053713), venous thromboembolism (MESH:D054556), deficiencies of (MESH:D007153), Thrombotic (MESH:D013927), anemia (MESH:D000740), lupus anticoagulant (MESH:C531622), loss of weight (MESH:D015431), antiphospholipid antibody syndrome (MESH:D016736), DVT (MESH:D020246), infertility (MESH:D007246), thrombocytopenia (MESH:D013921), coagulation abnormality (MESH:D001778), testicular atrophy (MESH:C567108), loss of appetite (MESH:D001068), thromboembolic (MESH:D013923), aneuploidy (MESH:D000782)
- **Chemicals:** paracetamol (MESH:D000082), testosterone (MESH:D013739), Nicoumarol (-), heparin (MESH:D006493)
- **Species:** Homo sapiens (human, species) [taxon 9606]
- **Mutations:** -677C>T, G20210A, 1298A>C, C677T, R506Q

## Figures

3 figures with captions in the complete paper: https://tomesphere.com/paper/PMC12961719/full.md

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Source: https://tomesphere.com/paper/PMC12961719