Anhidrotic ectodermal dysplasia (AED), or Christ-Siemens-Touraine syndrome, is an X-linked recessive dermatosis. Rare in incidence, it affects 1 in 100,000 births, mostly boys. Through this observation, we detail the clinical signs that led us to suspect the diagnosis, how this pathology was confirmed, and the therapeutic management we carried out. We present a case of a 10-month-old boy presenting with altered manifestations affecting almost all the ectodermal structures like skin, hair, nails, teeth, sebaceous glands, sweat glands, and tear glands. He also had complete anodontia and a dry mouth. A multidisciplinary treatment was given to the patient with the collaboration of various health professionals. Although Christ-Siemens-Touraine syndrome is a rare condition, it is vital to recognize it early to improve care and prognosis for these patients, while mitigating the psychological impact of the condition on both children and parents.

Hypohidrotic ectodermal dysplasia (HED) is a rare genetic disorder caused by a mutation in either the ectodysplasin (EDA), ectodysplasin A receptor (EDAR), EDAR associated via death domain (EDARADD), or Wnt family member 10A (WNT10A) genes that result in impaired development of ectodermal-derived structures. The literature defines two types of ectodermal dysplasia, which are hypohidrotic and hidrotic. X-linked hypohidrotic ectodermal dysplasia (XLHED), also known as Christ-Siemens-Touraine syndrome, is the most common form and is a variant of ectodermal dysplasia characterized by a classical triad of hypo/adontia, hypohidrosis, and hypotrichosis; whereas, hidrotic type of ectodermal dysplasia, also known as Clouston syndrome, is characterized by a triad of onychodysplasia, hypotrichosis, and palmoplantar hyperkeratosis while sparing the sweat glands. Symptoms of XLHED can begin early in life between the ages of one month to 23 months. XLHED is more commonly seen in males due to the x-linked characteristics of the gene mutations. This disease can be diagnosed by physical exam alone, or in combination with molecular genetic testing. XLHED specifically has an estimated occurrence of one in every 20,000 newborns worldwide. Approximately 5,000 people in the United States have the disease.  In this case report, we present an adult patient diagnosed with XLHED. Our objective is to emphasize the significance of early diagnosis, advocate for a multidisciplinary management approach, and shed light on the potential of recombinant protein and targeted gene therapy for further research. By raising awareness of this condition, we aim to improve patient outcomes not only in newborns but also in adults who have already been diagnosed with XLHED.

Hereditary ectodermal dysplasias are a complex group of inherited disorders characterised by abnormalities in two or more ectodermal derivatives (skin, nails, sweat glands, etc.). There are two main types of these disorders - hidrotic and hypohidrotic/anhidrotic ectodermal dysplasias. Hypohidrotic ectodermal dysplasia (HED) or Christ-Siemens-Touraine syndrome (OMIM: 305100) occurs in 1 out of 5000-10,000 births [19] and has an X-linked recessive inheritance pattern (X-linked hypohydrotic ectodermal dysplasia - XLHED) [2]. The main cause of XLHED is a broad range of pathogenic variants in the EDA gene (HGNC:3157, Xq12-13) which encodes the transmembrane protein ectodysplasin-A [4]. We report here the case of a patient with a novel inherited allelic variant in the EDA gene - NM_001399.5:c.337C>T (p.Gln113*) - in the heterozygous state. Targeted family member screening was conducted and other carriers of this EDA gene pathogenic variant were identified and phenotypically characterised. The patient subsequently underwent in vitro fertilisation with preimplantation genetic testing for monogenic diseases (PGT-M).

Ectodermal dysplasias (ED) are a group of rare genetic disorders characterized by congenital defects involving two or more ectodermal structures. Christ-Siemens-Touraine syndrome or hypohidrotic ectodermal dysplasia is the commonest form of ED. Hypohidrotic ectodermal dysplasia (HED) is an X-linked disorder characterized by excessively dry skin due to the absence of sweat glands (anhidrosis), sparse body hair especially on the scalp and eyebrows (hypotrichosis), brittle nails, absence of sebaceous glands (asteatosis) and malformed or absent teeth. Oral manifestations include oligodontia or complete anodontia, conical teeth, underdeveloped alveolar ridges, generalized spacing and delayed eruption of permanent teeth. This case report discusses a classical case of HED and the options for rehabilitation in a growing patient. A thorough knowledge about the clinical manifestations of ED will lead to proper diagnosis and appropriate treatment plan thereby leading to significant improvements in esthetics, phonetics and masticatory function in ED patients, which in turn leads to improved quality of life in these individuals.
UNASSIGNED: Abdulla AM, Almaliki AY, Shakeela NV, et al. Prosthodontic Management of a Pediatric Patient with Christ-Siemens-Touraine Syndrome: A Case Report. Int J Clin Pediatr Dent 2019;12(6):569-572.

Hypohidrotic ectodermal dysplasia is a common variation of ectodermal dysplasia, characterized by hypohidrosis (or anhidrosis), hypotrichosis, hypodontia, and other distinct facial features. Furthermore, ocular tissues of ectodermal origin may also be affected in this disease. The most common ocular manifestations of hypohidrotic ectodermal dysplasia are dry eye, madarosis, alterations in the meibomian glands, abnormalities in the nasolacrimal duct, and infantile glaucoma. Herein, author reports a case of hypohidrotic ectodermal dysplasia in a 12-year-old Indian boy with dry eye and lacrimal sac mucocele.

Hypohidrotic ectodermal dysplasia (HED) is a genetic skin condition presenting as hypohidrosis, hypodontia, and hypotrichosis, resulting in an important burden for affected families. The most common form of HED has an X-linked inheritance and female carriers have the option of prenatal or preimplantation genetic testing (PGT) to avoid transmission of the disease. A combined PGT for a mutation in EDA gene and aneuploidies in a Mexican carrier of X-linked HED is reported.
Ovarian stimulation and assisted reproduction procedures were performed in a private academic medical center. PGT for a novel c.707-1G>A (rs886039466) mutation in EDA gene and chromosomal aneuploidies was performed by massive parallel and Sanger sequencing.
In the first PGT, the transfer of two blastocysts did not result in a pregnancy. An accumulative stimulation approach was decided to improve pregnancy chances for a second PGT procedure. Three ovarian stimulations were performed and 10 blastocysts coming from fresh and vitrified oocytes were genetically analyzed. A single embryo transfer produced a healthy non-carrier euploid girl.
PGT combining aneuploidy and mutation analyses is an alternative for female carriers of X-linked and other Mendelian disorders in Latin-American countries. In the era of genomic and personalized medicine, medically assisted reproduction techniques, such as PGT, are shifting from only infertility to preventive genetics.

Ectodermal dysplasia exhibits a classic triad of hypohidrosis, hypotrichosis, and hypodontia. Self- mutilation could be due to organic or functional causes. The occurrence of selfmutilation with functional cause represents a diagnostic challenge to practitioners. In most of the instances dentists are the first to recognize patient with ectodermal dysplasia as they report primarily with a complaint of missing teeth. The most common type is hypohidrotic ectodermal dysplasia (Christ-Siemens-Touraine syndrome). A thorough knowledge of this disease with multidisciplinary approach aids in successful outcome of the treatment. This is an unusual case report of Christ-Siemens-Touraine syndrome with selfmutilation.