It is hard to imagine the suffering of the parents whose children age literally before their eyes - 7-8 times faster than normal at the age of 12-13 years old.
This is progeria (ancient Greek. Προσ-- super, γέρων - an old man) - a rare genetic defect in which the changes of the skin and internal organs are caused by premature aging of the body. Scientists from the United States report that they are close to creating methods of treatment of this disease.
There are two types of progeria - infant (Hutchinson (Hutchinson-Guildford syndrome) and adult progeria (Werner syndrome).
In the entire history of the world medicine no more than 80 cases of progeria were recorded, including a 13-year-old girl Haley Okins, 7-year-old Ashanti Elliott-Smith, and 12-year-old Ontlametse Phalatse from the town of Hebron near Johannesburg, who is the only known progeria patient among blacks. Also well known in the world is recently deceased American TsimFuckus, a YouTube user who suffered from adult progeria and had a video blog.
The cause of infant progeria is mutation of LMNA gene, encoding lamin A. Lamins are proteins that build a special layer of the shell of the cell nucleus. In a few families the disease was registered in the offspring of consanguine marriages, which suggests the possibility of autosomal recessive type of inheritance. In the cells of the skin of patients violations of repair mechanisms of DNA were found as well as the division of connective tissue cells and atrophic changes of the two main layers of the skin - the epidermis and dermis, and the disappearance of subcutaneous fat.
Although infant progeria may be congenital, most patients with clinical signs usually do not manifest them immediately after birth, but only at the age of two to three. The child's growth slows down dramatically; there are marked atrophic changes in the dermis, subcutaneous tissue, especially in the face and extremities. The skin becomes thin, dry and wrinkly. There may be areas of hyperpigmentation on the body.
The veins start showing through the thin skin. The patients have large head, frontal tubercles protruding over a small sharp ("avian") face with a beak nose, the lower jaw is underdeveloped. Also observed are muscle atrophy, degenerative processes in the teeth, hair and nails; marked changes in osteoarticular system, myocardium, hypoplastic genitalia, impaired lipid metabolism, cataract, and atherosclerosis.
Life expectancy of children suffering from progeria is 13 years. Most sources indicate the age of death from 7 to 27, and cases of the patients reaching adulthood are rare. Only one known case of a patient who survived the 27-year milestone is a Japanese male described by Ogihara and others in 1986 who lived to the age of 45.
Adult progeria is an autosomal recessive mode of inheritance. The defective gene in this case is quite different than in children. It is called WRN and encodes a vital enzyme. However, as in the case of infant progeria, mutations in this gene cause nearly the same effects: "self-repair" ability of the DNA and metabolism of connective tissue are affected.
Histology: flattening of the epidermis, sclerosis of the connective tissue, atrophy of the subcutaneous tissue with the replacement of its connective fibers. Clinically, the disease is manifested by a sudden onset in puberty. It is marked by stunted growth and symptoms of hypogonadism. Usually in their third decade of life the patients turn gray and lose hair, develop cataract, the skin gradually thins out and there is subcutaneous tissue atrophy on the face and extremities, resulting in particularly thin arms and legs. The patients develop osteoporosis, metastatic calcification of soft tissues, and rarely osteomyelitis. Often the disease is accompanied by diabetes whose symptoms manifest as symptoms of generalized atherosclerosis, commonly identified in patients 30-40 years of age. There are cases of malignant tumors (e.g., skin cancer, sarcoma and adenocarcinoma).
The prognosis for recovery is poor and most patients die from complications of atherosclerosis and cancer.
Although the disease was first described in the late 19th century, until recently doctors were powerless to help these kids and they grew old before the eyes of their parents, who knew from the beginning that their children were doomed.
However, there is hope. A group of American scientists headed by Professor Francis Collins, previously involved in the human genome studies, found a method of treating progeria. Although the scientists made only first steps in this direction, as the professor Collins said, intuition tells him that he and his colleagues are on the right track.
Scientists managed to restore the normal functioning of cells extracted from the bodies of children suffering from progeria with rapamycin - a substance widely discussed in the international scientific community. Rapamycin is a product of life of a rare bacteria living in the ground. Scientists have found that rapamycin is able to prolong the life of mammals. It also prevents rejection of transplanted organs and has antitumor properties.
Francis Collins' group was able to remove pathological protein progerin through the introduction of rapamycin in patients' cells. This protein causes the disease, premature aging and death of children suffering from it. There is a possibility that progerin is formed from the "normal" proteins of lamins predecessors, the same ones that encode the gene LMNA. If the gene mutates, the lamins are converted into pathogenic protein progerin.
The cells "cured" by rapamycin not only began normal functioning, but also lived longer than the normal ones, although before they died much earlier than healthy cells, says Francis Collins. Now, American molecular biologists along with the doctors plan to start clinical studies of rapamycin in the fight against infant progeria.
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