BACKGROUND: Ectodermal dysplasias are a group of >200 clinically and congenitally heterogeneous disorders characterized by abnormal development in the ectodermal structures, such as hair, nails, teeth, and sweat glands. We report here the clinical and molecular genetic analysis of five Greek families with different types of ectodermal dysplasia (ED).
METHODS: The study involved 15 individuals from 5 Greek families that included 8 ED patients, 5 carriers of recessive X-linked or autosomal ED, and 2 healthy relatives. After genetic counseling, the parents signed an informed consent form before subsequent genetic testing.
METHODS: Genomic DNA was isolated from white blood cells of all studied individuals. The search for mutations was realized in patients\' DNA samples using next-generation sequencing (NGS) gene panel, whole exome sequencing (WES), chromosomal microarray analysis (CMA), and multiplex ligation-dependent probe amplification (MLPA) technique.
RESULTS: The clinical diagnosis of common X-linked recessive hypohidrotic ectodermal dysplasia (HED) was suspected in five male patients with partial anodontia of baby and permanent teeth, hypohidrosis, and thin hair from three families. All HED patients were hemizygous for deletions in the EDA1 gene (Xq13.1): three related patients had a 20 bp deletion, one had a 19 bp deletion, and one had a 180 bp deletion. A female patient had the rare autosomal dominant syndrome of ankyloblepharon-ectodermal dysplasia-cleft lip/palate (AEC) caused by heterozygous missense mutation in the TP63 gene (3q28) that appeared de novo. Two siblings with hypotrichosis and hypodontia, a female and a male, had two pathogenic mutations in compound heterozygosity in the TSPEAR gene (21q22.3); therefore they presented with ectodermal dysplasia type 14 (ECTD14).
CONCLUSIONS: Clinical and molecular genetic analysis may set an accurate diagnosis of different types of ED. In the reported families, genetic diagnosis and genetic counselling assisted the parents to view their children\'s condition realistically and to cooperate with the specialists who will contribute to the best possible treatment for their children.

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.

The ectodermal dysplasias (EDs) constitute a group of disorders characterized by abnormalities in two or more ectodermal derivatives, including skin, hair, teeth, and sweat glands. The purpose of the current study was to evaluate ocular manifestations in pediatric patients with ED.
Retrospective case series including consecutive ED subjects who were treated in the ophthalmology department at the Children\'s Hospital of Philadelphia over a 12-year period (2009-2020). Main Outcome Measures were ocular and ocular adnexal abnormalities.
Thirty subjects were included: 20 males (67%), mean age of 4.5 years (range 0.3-18). Patients with different subtypes were included, with the hypohidrotic ED and ectrodactyly-ectodermal dysplasia-clefting variants being most prevalent. Most common findings were: lacrimal drainage obstruction in 12 (40%) including punctal agenesis in 10 (33%), refractive errors in 13 (43%) and amblyopia in 6 (20%). A new finding of eyelid ptosis or eyelash ptosis was demonstrated in 11 subjects (37%), mostly associated with TP63 or EDA1 genes variants.
Ectodermal dysplasias are associated with various ocular pathologies and amblyopia in the pediatric population. We report a possible genetic association between lash ptosis and EDA1 gene, and eyelid ptosis and TP63 or EDA1 genes variants.