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The concurrence of multiple genetically unrelated inherited diseases is rare and complicates analgaesic or anaesthetic management. Type I neurofibromatosis (NF)—also known as Von Recklinghausen’s disease—is an autosomal dominant disease caused by a mutation in the NF1 gene on chromosome 17; it has a prevalence of 1 in 2,500–3,500 live births and accounts for 80% of all NF cases.1,2 Approximately half of all type I NF cases are inherited, while the rest are de novo mutations.2 The classical features of type 1 NF include benign tumours of the peripheral nerves (i.e. neurofibromas), pigmented milky-brown skin lesions, freckles in unexposed areas such as the armpits and iris hamartomas (i.e. Lisch nodules).3 While most patients are usually asymptomatic, these features can result in compressive radiculopathies or neuropathies. Notably, the clinical presentation is quite variable even between affected members of the same family.2 Type I NF can be associated with first-trimester miscarriages and obstetric patients often require a Caesarean section delivery due to complications such as pelvic neurofibromas, pelvic bone abnormalities and kyphoscoliosis.3
Adults with type I NF can develop multiple cutaneous and subcutaneous neurofibromas which increase in number and size throughout their life.3 Plexiform neurofibromas can cause deformities, pain and functional problems and may sometimes become malignant. Osteopaenia, osteoporosis, bone overgrowth, short stature, macrocephalia, scoliosis, skeletal dysplasia (particularly of the sphenoid bone and vertebral wing) or pseudoarthrosis may also be present.3 Other alterations include arterial hypertension, vasculopathy, intracranial tumours, malignant peripheral nerve sheath tumours and, occasionally, seizures or hydrocephalus. Cognitive deficits and learning difficulties commonly occur in 30–45% of adults with NF, along with an increased risk of cancer.3
Most inherited hypercoagulable disorders are due to deficiencies of proteins C or S and antithrombin III, which occur in 15% of venous thrombosis cases.4 From a pathophysiological point of view, factor V Leiden (FVL) is the most common causative factor in this group of diseases.4 A FVL defect results from a mutation in the G1691A gene that encodes clotting factor V, which is inherited as an autosomal dominant trait; this leaves factor V resistant to inactivation by factor V-activated protein C.4,5 In the normal population, up to 3–5% of people carry the FVL mutation.6 Pregnant women...