Ectodermal dysplasias (ED) are rare genetic diseases characterized by a developmental abnormality of at least two of the following ectodermal derivatives: teeth, nails, pilosity and glands. In the hypohidrotic form (HED), dental abnormalities (oligodontia, hypodontia) and the decrease or even the absence of sweating are predominant. The lack of sweating, and therefore of the regulation of core body temperature, can impact the daily lives of patients as soon as the ambient temperature exceeds 23-24 ° C.~Core body temperature is one of the players of the internal biological clock that regulates sleep. Indeed, sleep is induced by a decrease in core body temperature concomitant with a peak of melatonin secretion. Consequently, the absence of sweating in HED and therefore the inability to lower core body temperature may explain the poor sleep quality reported by patients. However, sleep disturbances have not been analyzed in the literature nor the relationship between sleep quality and core body temperature in patients with HED.~The sleep of patients with HED who are followed at the national reference center for rare diseases of the skin and mucous membranes of genetic origin (MAGEC center) of the Necker-Enfants Malades hospital will be evaluated and compared to sleep of healthy controls screened within in the patient's family.~The main objective of the study is to compare the sleep efficiency evaluated on actigraphy between HED patients and healthy controls.~Sleep efficiency will be measured by means of actigraphy during 10 days and one overnight polysomnography, together with continuous recording of proximal and distal skin temperature during 10 days, one-off measurement of sweating by a sweat test and urine melatonin assay over 24 hours.~Subjective sleep quality will also be assessed by means of questionnaires in patients and healthy controls. Finally, patients with HED will also have a standardized psychological and neuropsychological assessment.
The aim of the study is to compare sleep efficiency by means of actigraphy in patients with hypohidrotic ectodermal dysplasia with healthy controls.~Sleep efficiency, assessed on actigraphy, sleep architecture assessed on on polysomnography, body temperature and urine melatonin levels will be compared between the patients with hypohidrotic ectodermal dysplasia with healthy controls.