Anhydrotic ectodermal dysplasia
The content of the article:
- Causes and risk factors
- Symptoms
- Diagnostics
- Treatment
- Possible complications and consequences
- Forecast
Anhydrotic ectodermal dysplasia is a hereditary disease caused by a genetic defect and characterized by congenital anomalies in the development of teeth, sweat and sebaceous glands, hair follicles and glands of the mucous membranes.
A triad specific to this pathology:
- an- or hypohidrosis (decreased activity of the sweat glands);
- hypo-, oligo- or adontia (defects in the dentition);
- hypotrichosis (paucity of hair).
Women can be carriers of the defective gene (there are no clinically significant manifestations of the disease in this case, the symptoms are minimal: impaired development of individual teeth, poor hair growth and decreased sweating), only males are ill. The complete symptom complex of the disease in women is paradoxical and extremely rare.
The disease was first described in 1848 by the French scientist J. Touraine; in 1913 by the German dentist J. Christ and in 1929 by the German dermatologist H. Siemens the clinical manifestations were detailed.
Currently, the exact frequency of occurrence of the pathology has not been established, presumably - in one newborn in 5000-10,000. The disease is detected on all continents, in representatives of all races equally.
Synonyms: Christ-Siemens-Touraine syndrome, hypohydrotic ectodermal dysplasia.
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Causes and risk factors
Currently, three genes are localized on different chromosomes, which can be the cause of the development of this disease. The number of mutations in these genes is known, at the moment there are more than 200:
- the EDA gene encoding the ectodisplasin-A protein is part of the Xq12-1 chromosome;
- the EDAR gene encoding the tumor necrosis factor receptor (a member of the EDAR superfamily) is mapped to chromosome 2q11-q13;
- TDARADD gene encoding ectodisplasin-A receptor associated adapter protein, chromosome 1q42.2‑
It is assumed that the effect of the genetic defect manifests itself at 2–5 months of intrauterine development.
Ectodermal dysplasia syndrome is transmitted in an autosomal recessive manner
The type of inheritance is X-linked, recessive: in this case, the pathological gene is localized on the sex X-chromosome and in women is suppressed by the dominant gene linked to another X-chromosome. Since men carry only one X chromosome, in which the genetic defect is located, and duplication of genes in such a situation is impossible, a detailed clinical picture with a variety of symptoms develops.
Symptoms
Clinical manifestations of the disease are caused by the incorrect formation of the external germ layer (ectoderm) in the prenatal period (structures formed from the ectodermal germ layer include teeth, epidermis and its derivatives, nervous system and sensory organs):
- short stature with a relatively large head;
- hair is sparse, thin, vellus, grows slowly, poorly pigmented, eyebrows and eyelashes are short, sparse or completely absent
- possible complete absence of hair or early hair loss;
- characteristic facial features, the so-called "old man's face" - a large forehead with protruding brow ridges and frontal tubercles ("Olympic forehead"), wide cheekbones, a sunken nose bridge, a small saddle nose with wing hypoplasia, sunken cheeks, full inverted "fish" lips with indistinct red border, massive chin, large deformed protruding and pointed upward ears with an abnormal curl ("satyr ears");
- late teething (in the period from 1 to 3 years), the typical sequence of teething is broken, milk teeth persist for a long time, permanent teeth are either not in the proper amount or are absent;
- conical (spine-like) shape of the front teeth, with a sharp (canine-like) cutting edge, the chewing surface of molars and premolars is atypically smoothed;
- change in bite;
- underdevelopment of the salivary glands (small salivation, dry mouth, hoarse low voice);
- dryness and fine wrinkling of the skin, especially around the eyes (in combination with hyperpigmentation and papular rashes, represented by degeneratively altered sebaceous glands);
- underdevelopment of the lacrimal glands, lack of tear fluid;
- photophobia;
- underdevelopment, less often - the complete absence of mammary glands;
- underdevelopment of the mucous glands of the respiratory tract and gastrointestinal tract, which causes a high predisposition to acute respiratory diseases, rhinitis, sinusitis, nosebleeds, bronchitis and diseases of the gastrointestinal tract;
- episodes of a sharp increase in body temperature due to impaired heat transfer due to underdevelopment of the sweat glands;
- oligophrenia of varying severity may be noted (although more often intelligence is preserved);
- isolation and social disorientation;
- problems with speech due to anomalies in the development of teeth and disturbances in nasal breathing;
- visual impairment of varying severity.
Ectodermal dysplasia is characterized by the conical shape of the anterior teeth with a sharp cutting edge
Diagnostics
The correct diagnosis is possible with a comprehensive assessment of the clinical picture and data from laboratory and instrumental studies, genetic examination:
- a general blood test (there is a decrease in the color indicator, the amount of hemoglobin is less than 100-90 g / l);
- biochemical blood test (a decrease in the content of albumin protein fractions and an increase in gamma fractions, a decrease in the content of calcium, phosphorus, iron);
- histological examination of a biopsy of the skin (the state of the sweat glands is analyzed);
- hair examination (a decrease in the diameter of the hair shaft, a change in its shape from round to flattened, atrophy or absence of the cortical layer are established);
- research of genes EDA, EDAR, TDARADD for mutations;
- prenatal (prenatal) DNA diagnostics.
Treatment
There is no specific treatment, the disease is lifelong.
Recommended activities:
- optimization of the microclimate to prevent the development of episodes of hyperthermia;
- using moisturizers;
- the use of moisturizing drops (such as "artificial tear") for the prevention of xerophthalmos;
- conducting courses of immunomodulatory therapy in order to prevent infectious complications;
- adherence to a sparing diet (soft food, medium temperature), adequate drinking regime (especially in the summer months);
- limiting to a minimum the time spent outdoors in hot weather, avoiding direct exposure to sunlight;
- dental prosthetics;
- early remineralizing therapy and dental fluoridation for the prevention of caries.
Possible complications and consequences
Complications of anhydrotic ectodermal dysplasia can be:
- the addition of secondary infections due to a decrease in immunity;
- gastrointestinal diseases (gastritis, duodenitis, peptic ulcer);
- diseases of the respiratory system (bronchial asthma, chronic bronchitis, sinusitis);
- diseases of the organs of vision (keratitis, conjunctivitis, blepharitis);
- inflammatory skin diseases;
- allergic diseases.
Forecast
With timely diagnosis, a slight degree of severity of clinical manifestations and adequate methods of preventing complications, the prognosis is favorable.
Prognosis is significantly impaired with multiple symptoms, late diagnosis, and lack of adequate care.
Olesya Smolnyakova Therapy, clinical pharmacology and pharmacotherapy About the author
Education: higher, 2004 (GOU VPO "Kursk State Medical University"), specialty "General Medicine", qualification "Doctor". 2008-2012 - Postgraduate student of the Department of Clinical Pharmacology, KSMU, Candidate of Medical Sciences (2013, specialty "Pharmacology, Clinical Pharmacology"). 2014-2015 - professional retraining, specialty "Management in education", FSBEI HPE "KSU".
The information is generalized and provided for informational purposes only. At the first sign of illness, see your doctor. Self-medication is hazardous to health!
