Generation and characterization of function-blocking anti-ectodysplasin A (EDA) monoclonal antibodies that induce ectodermal dysplasia

Development of ectodermal appendages, such as hair, teeth, sweat glands, sebaceous glands, and mammary glands, requires the action of the TNF family ligand ectodysplasin A (EDA). Mutations of the X-linked EDA gene cause reduction or absence of many ectodermal appendages and have been identified as a cause of ectodermal dysplasia in humans, mice, dogs, and cattle. We have generated blocking antibodies, raised in Eda-deficient mice, against the conserved, receptor-binding domain of EDA. These antibodies recognize epitopes overlapping the receptor-binding site and prevent EDA from binding and activating EDAR at close to stoichiometric ratios in in vitro binding and activity assays. The antibodies block EDA1 and EDA2 of both mammalian and avian origin and, in vivo, suppress the ability of recombinant Fc-EDA1 to rescue ectodermal dysplasia in Eda-deficient Tabby mice. Moreover, administration of EDA blocking antibodies to pregnant wild type mice induced in developing wild type fetuses a marked and permanent ectodermal dysplasia. These function-blocking anti-EDA antibodies with wide cross-species reactivity will enable study of the developmental and postdevelopmental roles of EDA in a variety of organisms and open the route to therapeutic intervention in conditions in which EDA may be implicated.

Carbimazole embryopathy: implications for the choice of antithyroid drugs in pregnancy

Maternal thyrotoxicosis, predominantly secondary to Graves' disease, affects 0.2% of all pregnancies. The Endocrine Society guidelines recommend the use of propylthiouracil as a first-line drug for thyrotoxicosis in pregnancy because of associations between carbimazole or methimazole and congenital anomalies. However, recent studies have highlighted the risk of severe liver injury with propylthiouracil. Here, we report another case with multiple congenital anomalies following in utero exposure to carbimazole and review the literature to consider the risks and benefits of available pharmacological treatments for thyrotoxicosis in pregnancy.

Aplasia cutis congenita associated with azathioprine

Aplasia cutis congenita is a rare skin condition characterized by the absence of localized or widespread areas of skin at birth. We are reporting a variant aplasia cutis congenita, which involved over 90% of the body surface area, which occurred in a baby born to a mother with pemphigus vulgaris who was on oral prednisolone and azathioprine. A case of extensive aplasia cutis congenita was seen and oral intake of azathioprine by the mother during pregnancy was suspected as an etiologic factor. The parents of the patient did not consent for biopsy or autopsy so the histopathological picture was not available and hence involvement of other systems could not be ascertained. Due, to financial constraints some of the investigations which might have helped in assigning the patient to a particular category of aplasia cutis such as karyotyping and CT scan brain could not be carried out.

Aplasia cutis congenita with skull defect in a monozygotic twin after exposure to methimazole in utero

BACKGROUND

Aplasia cutis congenita (ACC) is a condition in which localized or widespread areas of skin are absent at birth. Defective lesions show complete absence of all layers of skin, occasionally extending to skull or dura. ACC is etiologically heterogeneous; many different etiologies including teratogens have been documented.

CASE

We describe the first reported case of a monozygotic twin with ACC after exposure to methimazole in utero. The female patient was born at 36 weeks gestation as the first child of monozygotic twins. The mother received methimazole between the 11th and 17th weeks of pregnancy because of transient hyperthyroidism. The second child did not have ACC. The patient had defects of the scalp, skull, and dura (7 x 5 cm) on the sagittal line of the parieto-occipital region. No other malformations were noted. The scalp defect has been treated daily with sterile physiological saline and petrolatum dressing in addition to intravenous antibiotics. Trafermin, a recombinant human fibroblast growth factor, was sprayed from day 6 to promote epithelialization of the scalp defect. On day 21, she had high fever due to infection of the defect lesion, which was controlled by povidone iodine dressing and intravenous antibiotics. The defect of the scalp was well healed after 6 weeks, but the skull defect remained unclosed.

CONCLUSIONS

We describe a rare case of a monozygotic twin with ACC and skull defect after methimazole exposure in utero. The findings of our case suggest that methimazole is a potential teratogen of ACC.

Aplasia cutis congenita after methimazole exposure in utero

We describe a patient who was exposed to the antithyroid drug methimazole during the first 6 weeks of gestation and was born prematurely with scalp and skull defects associated with facial asymmetry. A review of the literature seems to support the hypothesis that methimazole is a potential teratogen. Although the risk of birth defects is low with clinically applied doses of the drug, it cannot be regarded as safe and should therefore be avoided in the treatment of pregnant women.

Aplasia cutis congenita after exposure to methimazole: a causal relationship?

We report a child with scalp aplasia cutis congenita, whose mother was treated with methimazole during pregnancy. The relationship between antithyroid drug administration during pregnancy and the occurrence of scalp defects is discussed, and the pertinent literature is reviewed.