Both ENG and ACVRL1 mutations lead predominantly to underproduction of the related proteins, rather than misfunctioning of the proteins. Diagnosis
Diagnostic tests may be conducted for various reasons. Firstly, some tests are needed to confirm or refute the diagnosis. Secondly, some are needed to identify any potential complications. Telangiectasias
The skin and oral cavity telangiectasias are visually identifiable on physical examination, and similarly the lesions in the nose may be seen on endoscopy of the nasopharynx or on laryngoscopy. The severity of nosebleeds may be quantified objectively using a grid-like questionnaire in which the number of nosebleed episodes and their duration is recorded.Digestive tract telangiectasias may be identified on esophagogastroduodenoscopy (endoscopy of the esophagus, stomach and first part of the small intestine). This procedure will typically only be undertaken if there is anemia that is more marked than expected by the severity of nosebleeds, or if there is evidence of severe bleeding (vomiting blood, black stools). If the number of lesions seen on endoscopy is unexpectedly low, the remainder of the small intestine may be examined with capsule endoscopy, in which the patient swallows a capsule-shaped device containing a miniature camera which transmits images of the digestive tract to a portable digital recorder. Arteriovenous malformations
Identification of AVMs requires detailed medical imaging of the organs most commonly affected by these lesions.
The neurologic deficits related to central venous thromboses does not necessarily affect one side of the body or one arterial or brain territory as is more common "arterial" strokes. Bilateral 6th cranial nerve palsies may occur, causing abnormalities related to eye movement, but this is rare.40% of people have seizures, although it is more common in women who develop sinus thrombosis peripartum (in the period before and after giving birth). These are mostly seizures affecting only one part of the body and unilateral (occurring on one side), but occasionally the seizures are generalised and rarely they lead to status epilepticus (persistent or recurrent seizure activity for a long period of time).In the elderly, many of the aforementioned symptoms may not occur. Common symptoms in the elderly with this condition are otherwise unexplained changes in mental status and a depressed level of consciousness.The pressure around the brain may rise, causing papilledema (swelling of the optic disc) which may be experienced as visual obscurations. In severely raised intracranial pressure, the level of consciousness is decreased, the blood pressure rises, the heart rate falls and there is abnormal posturing.Focal neurologic deficits may occur hours to days after the headache in 50% of cases, this may present as hemiparesis (unilateral weakness) if due to infarction of the frontal or parietal lobe which are drained by the vein of Trolard. Focal deficits may also present as aphasia or confusion if the vein of Labbe (responsible for draining the temporal lobe) is affected.