Crural Ulcers at Lower Limbs: Acquired or Genetic Pathology?

Disclosure: This work is supported by Associazione Romana Ricerca Dermatologica (ARRD). A 50-year-old man presented with bilateral, wide, painless, crural ulcers of 1-year duration on his lower legs. In addition to arterial hypertension, chronic glomerulonephritis, and chronic obstructive bronchopneumopathy (COBP), the patient experienced 3 transient ischemic attacks (TIAs). There was no family history of thromboembolic disease. Cutaneous ulcers were characterized by oval shape, rolled borders, and sticky, suppurative coating with abundant granulation tissue (Figure 1). Laboratory and immunological examinations revealed azotemia 24 mg/dL (normal 9–23 mg/dL); creatinine 1.9 mg/dL (normal 0.7–1.5 mg/dL); immunoglobulin E (IgE) 400 Ul/mL (normal 1 The altered thermolabile protein, codified by the mutated MTHFR gene, could lead to hyperhomocysteinemia, which is a high risk factor for coagulation disorders.² In this patient, homocysteine serum level was 11.86 µmol/L (normal 3 The thrombophilic screening in this patient identified a MTHFR mutation in heterozygous state. The MTHFR gene encodes a homologous enzyme involved in methionine and cysteine synthesis through methylation and trans-sulfuration pathway.⁴ This reaction is catalyzed via vitamins B12 and B6 as cofactors.¹ Methylene tetrahydrofolate reductase gene mutation could be linked with the presence of a thermolabile variant of its protein that leads to hyper-homocysteinemia (Table 3), which is a risk factor for cardiovascular diseases.² Kank et al.⁵ classified hyperhomocysteinemia as: • Mild: 15–30 µmol/L • Intermediate: 30–100 µmol/L • Severe: > 100 µmol/L. Methylene tetrahydrofolate reductase gene mutation may be associated with congenital malformations, such as spina bifida, anencephaly, heart, kidney, or skeletal (limbs and cranial) malformation^1,6,7 in the homozygous state. In this state, the first thrombotic sign appears after 30–40 years, and it is rarely associated with hyperhomocysteinemia. In the heterozygous state, MTHFR mutation is a risk factor for atherosclerosis, whether linked to acquired risk factors (eg, cigarette smoking, high blood pressure, and hypercholesterolemia), physical inactivity, diabetes, gender (male), oxidant agent exposure, or nutritional deficiencies (eg, folate and vitamins B12 and B6).^8,9 McCully¹⁰ first realized a pathogenetic correlation between hyperhomocysteinemia and vascular disease. Many epidemiological and clinical studies confirmed these data, showing that the mutated enzyme could modify the coagulation system phases (ie, platelet, hemocoagulative, and fibrinolytic phases). Many authors demonstrated that MTHFR gene mutation can: • Change the physiological endothelium production of nitric oxide (NO), altering NO-induced vessel vasodilatation¹¹ • Activate a growth factor, NF-kB, promoting hyperplasia of vessel smooth muscle cells¹² • Increase thromboxane A2 (TXA2) synthesis¹³ • Affect Leiden’s V factor, VW, and protein C synthesis^14,15,16 • Inhibit thrombin-thrombomodulin binding, increasing the insoluble fibrin concentration.^16,17 The treatment of a vascular thrombotic state varies according to the underlying causes. In this case, some authors suggested different therapies, including the following: • Folic acid and vitamins B6 and B12 • Acetylsalicylic acid because of its TXA2 synthesis inhibition • Antioxidant agents (vitamins E, C, A).^18,19 The authors chose the following therapy regimen: folic acid (5 mg/die), vitamin B6 (750 mg/die), vitamin B12 (1.5 mg/die), vitamin B1 (750 mg/die), and acetylsalicylic acid (100 mg/die), which resulted in local disinfection for a year with encouraging results. Conclusions In some cases, cutaneous ulcers do not originate from primitive cutaneous pathologies; however, they could represent an epiphenomenon of thrombotic diseases with genetic pathogenesis. In the authors’ patient, the presence of congenital and acquired disorders has probably contributed to reduced C protein, S protein, and AT III activity and could explain the severe and diffuse thromboembolic pathologies observed. These multiple associations, which appear to be rare, should be investigated more systematically in the presence of cutaneous ulcers with uncertain pathogenesis. At present, the multifactorial origin of thrombosis is more frequently evoked, but clear understanding of the real clinical efficacy of potential therapeutic intervention has yet to be realized. Treatment varies according to the underlying causes; however, vitamin supplementation, such as folic acid, pyridoxine, and vitamin B12 supplementation, is generally effective. In some circumstances, it is necessary to start an antiaggregant therapy for local disinfection of ulcers.