Overview.
Pseudoxanthoma elasticum is a recessive disorder in which a mutation in the ABCC6 gene leads to breakage and calcification of elastic fibers in connective tissues, and involves the skin, eyes and blood vessels. The disease is “pseudodominant” in 10% of patients and is very rare, with an incidence of 1 in 100,000 to 1 in 25,000, and a male-to-female ratio of 1:2.
Causes
The function of the ABCC6 gene is not clear, and its etiology and pathogenesis are not clear. It may be related to familial inheritance, endocrine disorders, and metabolic disorders.
Symptoms
1. Skin damage
Starting from childhood, it appears in the skin folds on both sides of the neck, around the umbilicus, armpits, popliteal fossa and groin, and is symmetrically distributed. Local skin thickening, poor elasticity, skin laxity, can be seen as a pinpoint to soybean-sized yellow verruca-like rash, mostly in clusters or fusion of net-like distribution. Some skin pores are enlarged, such as “plucked chicken skin” appearance.
2. Cardiovascular damage
Including hypertension, coronary heart disease, peripheral vascular disease and endocardial fibrosis and calcification. Involvement of limb arteries may result in weakened or absent pulse and intermittent claudication. Some patients may have angina pectoris and congestive heart failure, but myocardial infarction and sudden death are rare.
3. Digestive tract lesions
Yellow tumor-like nodular lesions, non-specific mucosal petechiae or erosions can be seen in the mucosa, which can be distributed in any part of the digestive tract, with the fundus of the stomach being the most common; a few patients can have gastrointestinal hemorrhage, which is mostly recurrent and more severe.
4. Eye damage
Gray to brownish-red curvilinear streaks in retinal blood vessels are the characteristic changes of this disease, which are radially and symmetrically distributed around the optic disc, and most of them occur several years after the appearance of skin lesions, and the patients are mostly 20 to 40 years old. Retinal fibrovascular endothelialization can lead to retinal hemorrhage, and macular involvement can lead to severe vision loss.
5. Cerebrovascular lesions
It can cause neuropsychiatric symptoms, mild hemiparesis, mental abnormality, subarachnoid hemorrhage, basilar artery insufficiency, epilepsy and so on.
6. Kidney damage
Kidney involvement can lead to hypertension, which can be combined with hyperthyroidism and diabetes mellitus.
Examination
1. Laboratory examination
(1) Blood routine: repeated gastrointestinal bleeding may have different degrees of anemia.
(2) Urine routine: occasional hematuria, some patients may have microscopic hematuria. Urine sugar is positive.
(3) Stool examination: there may be positive fecal occult blood test.
(4) Biochemical examination: If combined with hyperthyroidism, thyroid hormone is elevated. If combined with diabetes mellitus, blood sugar will be elevated.
2. X-ray examination
Chest X-ray shows left ventricular hypertrophy, which may be accompanied by aortic calcification.
3.Angiography
Angiography can show narrowing or occlusion of the arterial lumen of the limbs, and renal artery stenosis can be found in patients with hypertension.
Diagnosis
The disease can be diagnosed on the basis of a yellow or orange rash in areas of high skin friction, thickening of the skin, poor elasticity, skin laxity, and gray to brownish-red curved streaks in the retinal blood vessels. Sometimes it may be necessary to differentiate it from primary hyperthyroidism and diabetes mellitus, which can be differentiated by history, clinical manifestations, and laboratory tests.
Treatment
There is no effective treatment for this disease, mostly symptomatic supportive therapy. For skin lesions, 1% procaine can be injected locally, which can sometimes stop the deterioration of the lesions, and plastic surgery can help to improve the appearance of the skin. If there is gastrointestinal bleeding, blood transfusion and hemostatic drugs should be given. Those with hypertension or coronary artery blood supply insufficiency need to undergo vasodilatation, anticoagulation therapy and give thrombolytic preparations, etc. Once heart failure and cerebrovascular accidents occur, they should be treated accordingly. In addition, the application of vitamin E or calcium has been reported to be effective in relieving skin lesions and eye symptoms.
Prognosis
The prognosis is good in most cases, but the occurrence of vascular lesions can be life-threatening in severe cases.