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Pregnancy and PXE

Lionel Bercovitch
Clinical Associate Professor of Dermatology
Brown University School of Medicine, Providence, RI

Introduction
Pseudoxanthoma elasticum (PXE) is a hereditary disorder which is characterized by (1) yellowish papules and plaques in the skin of the neck and flexural areas ("pseudoxanthomas"), (2) angioid streaks in the retina, resulting from breaks in Bruch's membrane of the choroid, and (3) cardiovascular and gastrointestinal complications related to abnormal elastic tissue in arterial walls. Bulletins, available from PXE International, entitled "PXE and the Primary Care Physician" or "PXE and the Dermatologist" offer detailed information about the disease.

The Effect of PXE on Pregnancy
Since there is no published data on large series of women affected with PXE, the true incidence of pregnancy-related complications is unknown.Berde et al reviewed 24 pregnancies in 9 women, published in 5 previous articles.Five women accounted for 8 instances of gastrointestinal hemorrhage due to abnormal blood vessels in 20 pregnancies. Neldner reported that 54 women noted significant worsening of skin, eye, and cardiovascular manifestations during pregnancy, but detailed corroborating analysis of obstetrical records is not available.
Viljoen et al did a retrospective analysis of 54 pregnancies in 20 South African women with PXE. In their series, no episodes of gastrointestinal hemorrhage were noted.
Hypertension was noted in 7/54 patients and was managed by traditional means (bed rest, diuretics, anti-hypertensives). No ocular or other cardiovascular problems were reported, but there appeared to be a slight increase in first-trimester miscarriage (12/54). Labor and vaginal deliver were uncomplicated. In this series as in previous reports, cosmetic worsening of abdominal skin laxity and striae appeared to be proportional to parity and weight gain during pregnancy (as one would expect even in non-PXE pregnancies). Flexural skin appears to remain stable.
Bercovitch et al (iv) studied 145 pregnancies in 56 women with PXE. The incidence of miscarriage was 12%. Their study found three pregnant womenaffected by gastric hemorrhage and three with worsening of skin lesions. Noocular or thromboembolic complications were reported. Hypertension during pregnancy was reported by 12% of women. Of the 56 women, seven (12%) had been advised by their physician not to become pregnant. The authorsconcluded that the incidence of PXE-related complications in pregnancyappears to be low, and pregnancy outcomes in PXE appear to be similar tothe general population.
It appears, therefore, that based on the single largest series in which obstetrical records were available, that fertility is normal, and the majority of women with PXE have a normal pregnancy, labor, delivery, and post-partum period. However, there is little argument that the potential for gastrointestinal or other hemorrhage exist, and hypertension and pre-eclampsia should be vigorously managed.

Effect of PXE on the Fetus
In Viljoen's series, the rate of premature delivery was in the expected range, and only 1/40 babies was born with a congenital malformation. In Berde's series 1, 20/22 infants were born in "good condition", one was stillborn following late trimester GI hemorrhage, and one died of congenital rubella syndrome). Two of three placentas showed calcifications of unknown cause. (Since the placenta is of fetal origin, one would not expect to see PXE related calcification of the placenta in an unaffected fetus). In Bercovitch'sseries, the incidence of stillbirth was 2%, but three of the four stillbirths were the result of cord complications or abruptio placentae, unrelated to PXE.
One stillbirth occurred within the month following a GI bleed, possibly from a peptic ulcer. The incidence of prematurity and low birth weight was within the range expected in the normal population.In summary, except for the consequences of severe maternal hemorrhage, which appears to be uncommon, PXE has no significant effect on the fetus. At this time, no tests exist for prenatal diagnosis, and clinical manifestations of the disease are not visible at birth.

Gynecological Aspects of PXE
In Viljoen's series 3, menarche occurred at the usual age, menstrual cycles were normal, and menorrhagia occurred with the expected frequency. No complications of oral contraceptive use were reported. Gynecologic and gynecologic surgical histories appeared unremarkable in their series. Viljoen raised the issue of whether other means of contraception should be considered because of the risk of thromboembolic complications in oral contraceptive users, but no data exists to support this concern in young women with PXE.

Genetic Counseling for Women with PXE
Offer genetic counseling to women of childbearing age with PXE or family history of PXE on either her or her partner's side. A detailed family tree and examination of multiple generations of the affected individual's family as well as that of the partner's is important. While current research has
suggested that PXE is inherited as an autosomal recessive disorder, the carrier frequency may be higher than previously thought and some carriers may exhibit mild subclinical signs. It is also important to note that there is parental consanguinity. Although scientists have found the gene for PXE (v,vi) encoding for the cellular transport protein ABCC6, a CLIA approved test is not yet available for clinical use. Until such a test is available, understand that genetic counseling is limited to risk assessment only.

Endnotes
1. Berde C, Willis DC, Sandberg EC (1983) Pregnancy in women with
pseudoxanthoma elasticum. Obstet Gynecol Surv 38: 339-344.

2. Neldner KH (1988) Pseudoxanthoma elasticum. Clin Dermatol. 6: 1-159.

3. Viljoen DL, Beatty S, Beighton P (1987): The obstetrical and
gynaecological implications of pseudoxanthoma elasticum. Brit. J. Obstet. Gynaecol. 94:884-888.

4. Bercovitch D, Montemuino M, Bercovitch L, Terry S, Campbell JL,
Lebwohl M (1998): Pregnancy and reproductive outcomes in
pseudoxanthoma elasticum. (Abstract) J. Invest. Derm. 110:571.

5. Le Saux O, Urban Z, Tschuch C, Csiszar K, Bacchelli B, Quaglino D,
Pasquali-Ronchetti I, Pope FM, Richards A, Terry S, Bercovitch L, de
Paepe A, Boyd CD. Mutations in a gene encoding an ABC transporter
cause pseudoxanthoma elasticum. 2000 Jun. Nat. Genet. 25, 223-227.

6. Bergen AA, Plomp AS, Schuurman EJ, Terry S, Breuning M, Dauwerse H, Swart J, Kool M, van Soest S, Baas F, ten Brink JB, de Jong PT. Mutations in ABCC6 cause pseudoxanthoma elasticum. 2000 Jun. Nat. Genet. 25, 228-231.

 

 

 

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