The placenta in pseudoxanthoma elasticum: clinical, structural and immunochemical study

Pseudoxanthoma elasticum - Genetics, pathophysiology, and clinical presentation

Pseudoxanthoma elasticum (PXE) is an autosomal-recessively inherited multisystem disease. Mutations in the ABCC6-gene are causative, coding for a transmembrane transporter mainly expressed in hepatocytes, which promotes the efflux of adenosine triphosphate (ATP). This results in low levels of plasma inorganic pyrophosphate (PPi), a critical anti-mineralization factor. The clinical phenotype of PXE is characterized by the effects of elastic fiber calcification in the skin, the cardiovascular system, and the eyes. In the eyes, calcification of Bruch's membrane results in clinically visible lesions, including peau d'orange, angioid streaks, and comet tail lesions. Frequently, patients must be treated for secondary macular neovascularization. No effective therapy is available for treating the cause of PXE, but several promising approaches are emerging. Finding appropriate outcome measures remains a significant challenge for clinical trials in this slowly progressive disease. This review article provides an in-depth summary of the current understanding of PXE and its multi-systemic manifestations. The article offers a detailed overview of the ocular manifestations, including their morphological and functional consequences, as well as potential complications. Lastly, previous and future clinical trials of causative treatments for PXE are discussed.

Clinical practice guidelines for pseudoxanthoma elasticum (2017): Clinical Practice Guidelines for Pseudoxanthoma Elasticum Drafting Committee: Clinical Practice Guidelines for Pseudoxanthoma Elasticum Drafting Committee

Pseudoxanthoma elasticum (PXE) is a progressive hereditary disease that affects tissues such as the skin, retina, blood vessels, and gastrointestinal tracts. Therefore, comprehensive medical care across clinical departments specialized in specific organs is needed to provide the best clinical practices to PXE patients. The Japanese version of clinical guidelines developed by the Japanese Dermatological Association was published in 2017, and aimed to promote equal accessibility of PXE-related medical care. Here, the English version of Japanese guideline is reported, and is intended to be worldwide reference for medical care of PXE.

Approach to the management of pregnancy in patients with pseudoxanthoma elasticum: a review

Management of pregnancy in patients with rare diseases is often guided by incomplete knowledge because of a lack of high-quality case control studies or single-centre experience. Pseudoxanthoma elasticum (PXE) is an autosomal recessive metabolic disorder that results in calcification of elastic fibres of the skin, retina, and arteries, leading to skin lesions, eventual central visual loss, and potential arterial insufficiency in most patients. It is due to mutations in ABCC6, which encodes the eponymous membrane transport protein. We review the literature on pregnancy in PXE, including the effects of the diseases on pregnancy and its complications, the effect of PXE on the foetus, and the effects of pregnancy on PXE, and conclude that in the majority of pregnancies in women with PXE, the outcome for mother, baby, and the disease is uneventful. We also provide recommendations for managing pregnancy in PXE.

Placental Calcification in Pseudoxanthoma Elasticum

Introduction: Pseudoxanthoma elasticum (PXE) is an inherited multisystem disorder of the elastic tissue and the objective of this case report is to correlate ultrasonographic and histological appearances of placental calcification in PXE. Clinical Picture: We report a case of a 37-year-old white woman with PXE, whose antenatal imaging showed a markedly echogenic placenta due to extensive calcification confirmed on postpartum placental histology. Outcome: There were no maternal or fetal complications in the antenatal period. A healthy baby of appropriate maturity and weight was delivered via Caesarean section and remained well at 6 months. Conclusion: The majority of cases of PXE is caused by mutations in the ABCC6 gene. Serious complications in pregnancy can include gastrointestinal haemorrhage, congestive heart failure and cardiac arrhythmia but has not been shown to be associated with markedly increased fetal loss or adverse reproductive outcomes as reported in previous literature. Apart from the cosmetic deterioration of the abdominal skin, there were few serious complications and most have normal pregnancies. Obstetric prognosis is dependent on the vascular damage caused by the illness. There is no basis for advising women with PXE to avoid becoming pregnant, and most pregnancies in PXE are uncomplicated. Key words: Angioid streaks, Echogenic placenta, Gastrointestinal haemorrhage

Advocacy groups as research organizations: the PXE International example

Advocacy organizations for genetic diseases are increasingly becoming involved in biomedical research, particularly translational research, in order to meet the needs of the individuals that they serve. PXE International, an advocacy organization for the disease pseudoxanthoma elasticum, provides an example of how research can be accelerated by these groups. It has adopted methods that were pioneered by other advocacy organizations, and has integrated these along with new approaches into franchizable elements. The model has been followed for other conditions and has led to the establishment of a common infrastructure to enable advocacy groups to initiate, conduct and accelerate research.

Connective tissue diseases: pseudoxanthoma elasticum, anetoderma, and Ehlers-Danlos syndrome in pregnancy

The relationship between pregnancy and diseases of the elastic fibers, such as pseudoxanthoma elasticum, cutis laxa, and anetoderma, is discussed in this article. Dermatologists and other physicians must be aware that these problems may be present in pregnant women and must also know how to counsel those who suffer from these diseases because they can have severe manifestations and consequences during or after this period for both the pregnant mother and her offspring.

Pseudoxanthoma elasticum and pregnancy

A 29-year-old woman affected by pseudoxanthoma elasticum gave birth to her second child in our department, thirteen months after the delivery of her first boy. Her care illustrates many of the potential risks of this rare autosomal systemic disorder. In order to detect any changes due to pregnancy, ophthalmologic and cardiologic screening examinations should be performed in the beginning of the pregnancy and repeated several weeks after the delivery. During labor, epidural anesthesia seems to be more advantageous.

Pregnancy and obstetrical outcomes in pseudoxanthoma elasticum

BACKGROUND

Pseudoxanthoma elasticum (PXE) is a genetic multisystem disorder characterized by calcified dystrophic elastic fibres in skin, retina and arteries. Much of the earlier literature on pregnancy in PXE contained reports of severe complications, leading some healthcare providers to advise women with PXE against becoming pregnant and some women with PXE to avoid pregnancy.

OBJECTIVES

To evaluate the obstetrical outcomes and the incidence of pregnancy complications in women with PXE and to determine if pregnancy is associated with an adverse effect on the course of the disease.

METHODS

Women with PXE (n = 407) answered detailed questionnaires regarding reproductive history and pregnancy as well as the course of their disease. The frequency of reported pregnancy outcomes and complications was determined. Severity indices for the major clinical manifestations of PXE were developed and correlated with gravidity of affected women aged 40 years or over.

RESULTS

Among the 306 respondents with PXE who had ever been pregnant, there were 795 pregnancies. Of these, 83% ended in live births and 1% in stillbirth. The median birth weight was within the normal range and the incidence of low birth weight for gestation was low. Hypertension occurred in 10% of pregnancies, gastric bleeding and retinal complications in < 1%, and 12% of pregnancies were associated with worsening of skin manifestations. There was no effect of gravidity and clinical severity on cutaneous (P = 0.07), ocular (P = 0.59) or cardiac (P = 0.42) manifestations of PXE in women aged 40+ years, nor did ever having been pregnant adversely affect these clinical severity indices. Of the 101 women who had never been pregnant, 17% made the decision because they were advised against becoming pregnant by a healthcare professional and 11% did not become pregnant because they feared an adverse outcome either in their pregnancy or disease.

CONCLUSIONS

PXE is not associated with markedly increased fetal loss or adverse reproductive outcomes. The incidence of gastric bleeding, although probably higher than in the unaffected population, is much lower than previously reported, and retinal complications are uncommon. Although a few pregnancies were associated with worsening of skin manifestations, there was no correlation of either gravidity or ever having been pregnant with ultimate severity of skin, ocular or cardiovascular manifestations. There is no basis for advising women with PXE to avoid becoming pregnant, and most pregnancies in PXE are uncomplicated.

Pseudoxanthoma elasticum: a clinical, histopathological, and molecular update

Pseudoxanthoma elasticum is an autosomally inherited disorder that is associated with the accumulation of mineralized and fragmented elastic fibers in the skin, Bruch's membrane in the retina, and vessel walls. The ophthalmic and dermatologic expression of pseudoxanthoma elasticum and its vascular complications are heterogeneous, with considerable variation in phenotype, progression, and mode of inheritance. Using linkage analysis and mutation detection techniques, mutations in the ABCC6 gene were recently implicated in the etiology of pseudoxanthoma elasticum. ABCC6 encodes the sixth member of the ATP-binding cassette transporter and multidrug resistance protein family (MRP6). In humans, this transmembrane protein is highly expressed in the liver and kidney. Lower expression was found in tissues affected by pseudoxanthoma elasticum, including skin, retina, and vessel walls. So far, the substrates transported by the ABCC6 protein and its physiological role in the etiology of pseudoxanthoma elasticum are not known. A functional transport study of rat MRP6 suggests that small peptides such as the endothelin receptor antagonist BQ123 are transported by MRP6. Similar molecules transported by ABCC6 in humans may be essential for extracellular matrix deposition or turnover of connective tissue at specific sites in the body. One of these sites is Bruch's membrane. This review is an update on etiology of pseudoxanthoma elasticum, including its clinical and genetic features, pathogenesis, and biomolecular basis.

Anesthesia for the parturient with pseudoxanthoma elasticum

We present our experience in the anesthetic management of two parturients with pseudoxanthoma elasticum. The first had an epidural catheter inserted for labor analgesia and ultimately had a forceps delivery. The second had a cesarean section under epidural anesthesia and had a complicated postoperative course. There were no untoward effects of regional anesthesia in either of these two women. The anesthetic implications for parturients with pseudoxanthoma elasticum are discussed.

Cardiovascular involvement in thalassaemic patients with pseudoxanthoma elasticum-like skin lesions: a long-term follow-up study

BACKGROUND

Congenital haemolytic anaemia may be associated with pseudoxanthoma elasticum (PXE)-like clinical manifestations.

METHODS

The cardiovascular system of 14 homozygous and double heterozygous beta-thalassaemia patients with skin and retinal vessel alterations similar to those in genetic PXE was analysed over a period of 12 years and compared with that of 13 relatives (five sets of parents, one single parent, two thalassaemic brothers), and that of the control group composed of 16, age- and sex-matched, thalassaemic patients.

RESULTS

All patients with clinical PXE-like skin lesions exhibited, by light and electron microscopy, dermal alterations and mineralization of elastic fibres identical to those typical of inherited PXE. None of the relatives and none of the control group showed clinical or structural findings of PXE. The follow-up started in 1988. After 12 years of clinical observation, six patients showed dramatic progression of skin involvement, angioid streaks had progressed in two subjects. One patient had recurrent gastrointestinal bleeding and underwent partial stomach removal for gastric artery aneurysm, one underwent colon resection for intestinal infarct, one patient had a transitory ischaemic attack, one died after an intracranial haemorrhage, two patients died from cardiovascular disease and one from neoplasia.

CONCLUSIONS

Thalassaemic patients with PXE-like skin lesions also manifest PXE-like vessel alterations that progress with time. Considering the severe outcome of these lesions, accurate monitoring should be routinely performed on the cardiovascular system of thalassaemic patients with PXE-like skin manifestations.