Ectodermal dysplasia (ED) was first proposed by Thurman in 1848. It is a diverse group of inherited disorders characterized by a congenital defect in two or more ectodermal structures. The primary manifestations are abnormalities in hair, teeth, nails or sweat glands [
1]. The inheritance mode includes autosomal dominant, autosomal recessive, X-linked dominant, and recessive. Currently, ED can be classified into the hidrotic or hypohidrotic types according to whether it involves sweat glands. Hypohidrotic ectodermal dysplasia (HED) has a birth prevalence rate of 1/50,000–100,000, and males with the disease show all or most of the typical clinical manifestations associated with the ectodysplasin A (EDA) gene, while female carriers show less severe symptoms [
2]. The X-linked type is the most common form of hypohidrotic ED. Prenatal diagnosis for this rare disorder is helpful in predicting potential postpartum hyperpyrexia or providing a basis for termination of pregnancy or suggesting the possibility of prenatal correction [
3,
4]. We reviewed the cases reported in the last 20 years, and a majority of the confirmed cases were diagnosed by genetic tests after birth. A prenatal tooth germ sonography has been suggested to detect X-linked hypohidrotic ED in some studies (Table
1), but it has not been used as a diagnostic basis in a broader setting. This is because not all the tooth germs could be accurately counted using ultrasound in middle pregnancy, and the risk of a false positive would probably increase unnecessary treatment [
11]. The prenatal diagnosis should be confirmed by combining ultrasound findings, family history, and genetic testing [
6]. Herein, we describe a rare fetal case of ED with an X-linked recessive family history that was diagnosed prenatally using ultrasound and genetic testing after diagnostic amniocentesis. Three-dimensional reconstruction CT of the induced labor fetus showed the same malformation of the alveolar as the prenatal ultrasound, and the pathological exam of the skin confirmed the hypohidrotic-type ED diagnosis.
Table 1
Cases of prenatal diagnosis of ectodermal dysplasia reported in PubMed in the last 20 years
| 2018 | 2 males | no tooth germs at all were detected in the mandible and 1 and 2, respectively, were detected in the maxilla. | EDA c.911A → G(p.Y304C). Y304 | Y | N Engl J Med |
| 2020 | Male | No tooth germ. | EDA c.574G | Y | Zhonghua Yi Xue Yi Chuan Xue Za Zhi |
| 2014 | 4 males, 2 females | All 6 cases reduced number of tooth germs and 5 of them had hypoplastic lower jaws. | p. P17GfsX81 p. P220_P225del p. R156H Exon3dupl p. R156H p. P220_P225del | Y | Ultraschall Med |
| 2005 | Male | ➖ | EDA inv. (x) (p22q13) | Y | Zhonghua Yi Xue Za Zhi |
| 2013 | Male | ➖ | EDA p.G11R | Y | Zhonghua Yi Xue Yi Chuan Xue Za Zhi |
| 2003 | Male | a small nose and thick, everted upper and lower lips. | ➖ | Y | J Ultrasound Med |
| 2021 | Male | thinner upper alveolar bones and fewer tooth germs. | EDA Xq13.1 | N | J Clin Ultrasound |