Aurora magazine

Hypoidrotic ectodermal dysplasia (HED) is a rare genetic disease with a prevalence of about 1 / 15,000-17,000. It affects ectodermal development and causes malformations to skin, hair, teeth and sweat glands.

There are three variants of HED, almost impossible to distinguish clinically and all characterized by a sweating disorder.

• Christ-Siemens-Touraine syndrome. It includes 80% of cases and is linked to the X chromosome. It affects only the male births.
• Autosomal recessive HED (AR);
• Autosomal dominant HED (AD).

The characteristic symptom of hypohidrotic ectodermal dysplasia is the absence of sweat glands. This causes a very reduced sweating if not completely absent, leading to recurrent episodes of hyperthermia. The body is unable to regulate its temperature, which makes the person intolerant to heat. Some episodes of hyperthermia can even be lethal.

The other symptoms of HED are sparse or absent hair, lack of teeth and thin skin. Furthermore, many patients have chronic conjunctivitis, caused by reduced tearing. Other symptoms are nasopharyngeal dryness and a series of asthmatic episodes. Those who suffer from the disease often face rounded, thin eyelashes and eyebrows, wrinkles around the eyes.

The disease is caused by mutations in the genes responsible for ectodisplasin / NF-κB. In the case of CST, the affected gene is the one that encodes the ectodisplasin-A protein. The other two may also be caused by abnormalities in the gene that codes for the EDAR-associated death domain protein (EDARADD).

Current treatments are mostly symptomatic. Modern dentistry helps to restore the function of the teeth, also improving their appearance. Regarding the absence of sweating, those suffering from HED must avoid prolonged exposure to heat sources. In the case of very young children, doctors recommend the use of wet clothing. These measures guarantee a normal life expectancy.

Source: orpha.net

Under the term "neural tube defects" comes a wide range of congenital malformations. All have early appearance, within 28 days of conception. The cause lies in defects of various kinds in the closure of the central nervous system and the structures connected to it.

In Italy, neural tube defects affect about 1 child every 1500 newborns. Neural tube defects can be "open" or "closed", depending on whether there is a deficit or an excess of tissues. The latter are more difficult to identify and often even less serious. However, they cause changes in the urinary system and often difficulty in moving and walking.

The most common form of neural tube defect is spina bifida. It is an "open" defect in which the nerve tissue of the spinal cord and meninges remains uncovered. This causes a series of very serious symptoms, including paralysis of the lower limbs, psychomotor retardation, deformations of the skeleton.
The causes of neural tube defects are both environmental and genetic. The most known and also the easiest risk factor to prevent is the lack of folic acid. Some antiepileptic drugs, diabetes, anemia and exposure to certain toxic substances also contribute. The latter factor is common especially in some developing countries.

Common prenatal screening tests are able to identify some neural tube defects. For example, ultrasound can detect spina bifida as early as the 14th week of gestation. For closed defects, however, they are often identified after birth and sometimes even after months or years. In this case, the diagnosis is made by clinical observation and magnetic resonance.

For the time being there are no definitive therapies for neural tube defects. A technique to correct spina bifida in utero is under development, but it is still being tested. In daily practice, we proceed to repair the lesions and any abnormalities of the urinary system.

Source: telethon.it

Von Recklinghausen's disease, also called neurofibromatosis type 1 (NF1), is an inherited genetic disease. It affects bones, skin and nervous system, manifesting itself with tumor formations all over the body.

The diagnosis of the disease is based on a series of unequivocal clinical signs, both on a physical and on a neurological level.

• Brain injuries. Over half of the patients show abnormalities in the brain, in the orbits or both. The cause is the neurofibromas of the disease and from which its scientific name derives. They often affect the optic nerve and the parenchyma. Bilateral optic glioma, for example, is one of the possible consequences of Von Recklinghausen's disease.
• Spots. Another typical symptom is also light brown spots, which must be more than six and at least 5 mm wide. After puberty they tend to become bigger, numerous and dark.
• Freckles. Those suffering from Von Recklinghausen's disease show multiple freckles in the armpit and groin area.

Among the possible complications related to the disease there are also tumors on the palate or tongue and skeletal deformations. In addition, some patients with mosaicism show symptoms only on one segment of the body.

Neurofibromatosis type 1 is caused by inherited genetic abnormalities in about 50% of cases. In these cases, the diagnosis is made by a history and observation of symptoms. In the other half of the cases, it is based on clinical symptoms. For the most ambiguous cases, the genetic test is used.

Source: news-medical.net

There is talk of mosaicism when the same person has cells within him with a different genetic heritage. It is therefore possible that they have a part of healthy cells and a part of cells affected by chromosomal abnormalities. Depending on the case, the condition can also affect particular types of cells, such as those of blood, skin and gametes.

At the basis of mosaicism there is an error in cell division during embryonic development. If the cells affected by the anomaly are few, it is possible that the effects on the individual are limited. If they were the majority, it becomes much more likely to manifest pathologies. For example, it is possible to have Down syndrome, Klinefelter syndrome and Mosaic turner.

The only method to have a reliable diagnosis of mosaicism is genetic testing and prenatal screening tests. The cells of the fetus are analyzed and the presence of cells with chromosomal abnormalities occurs. If successful, continue with further genetic tests. In this way an estimate is made of the number of anomalous cells and, consequently, of the severity of the mosaicism.

The effects of mosaicism vary greatly depending on the severity and the cells involved. In general, it is difficult to predict with confidence the effects of such a condition. A chromosomal abnormality present in most cells is almost equivalent to an abnormality present in 100% of cells. A low percentage of abnormal cells may have no effect on the individual, but have repercussions on his offspring. Current genetic testing and fetal DNA testing can unveil this possibility in time.

Source: nytimes.com