It is a rare genetic disease that affects the children of people who mate despite being related. It belongs to the syndrome of chromosome instability.
This disease was first described by David Bloom in 1954. He also found that people suffering from it have certain physical characteristics. Belong to them:
1. Height and weight disorders, i.e. low birth weight and growth retardation. More than half of children with Bloom’s syndrome up to the age of eight are physically much less developed than their healthy peers. The short stature (short stature) of the child is visible already in the prenatal period and lasts until the end of life.
2. Characteristic body structure. The lack of subcutaneous fat contributes to the bird’s appearance of the child’s face – it is very long, narrow with a very prominent nose. The entire skull is unnaturally long and narrow. There is also underdevelopment of the cheeks and lower jaw. Babies have large and protruding ears and long and disproportionate limbs. This applies primarily to the hands. Hand and foot contractures develop over time. In addition, sick children are characterized by rapid movements, which are often referred to as birds.
3. The appearance of the skin in patients, it also deviates from the norm. There are numerous telangiectasias (vascular spider veins) and pigmentary changes, especially after exposure to sunlight. Redness appears on the hands and hands, and on the face they take the shape of a butterfly. Mouth ulcers or inflammation of the corners of the mouth and café au lait spots (congenital skin eruptions with a light brown stain that resembles the color of coffee and milk) are also common problems.
4. Patients usually have a high tone of voice.
5. Endocrine disorders. Patients suffer from hypogonadism, i.e. a defect in the reproductive system manifested by dysfunction of the ovaries or testicles.
6. Fertility disorders. Men with mutated BLS proteins are sterile. Women have reduced fertility and enter menopause earlier than their healthy peers. Pregnancy in women suffering from Bloom’s syndrome is at risk of premature delivery.
7. Patients’ intelligence is usually normal, but there is a possibility of mild mental impairment.
The incidence of the disease
Bloom’s syndrome is most common among Ashkenazi Jews, but cases have also been reported in Japan and elsewhere. The largest number of patients (170 cases) was recorded in the United States, where relatives consent to marriages more often than in other countries. The male-female disease ratio is 1,3: 1.
The cause of Bloom’s syndrome is a mutation in the BLM gene having a locus on the long arm of the 15th chromosome. The BLM protein encoded by this gene belongs to the DNA helicase family and participates in the process of maintaining genomic stability. In 1989, scientists established that the main biochemical defect in people with this syndrome is the overproduction of superoxide anion, which inefficiently removed may be responsible for increased sister chromatid exchange and chromosome fragility.
The difficult fate of the sick person
One of the characteristics of Bloom’s syndrome is immunity disorders manifested by a decrease in the level of antibodies, and thus frequent infections of the respiratory tract and the digestive system. Moreover, it has been proven that patients are more susceptible to neoplastic diseases, mainly leukemias, lymphomas and adenomas of the digestive system. These diseases lead to death, usually in the second or third decade of life.
The risk of cancer in patients with Bloom syndrome, compared to the entire population, is extremely high – from 150 to 300 times. Medical statistics show that 20 percent. patients develop acute myeloid leukemia, malignant lymphoma, or gastric cancer.
Unfortunately, even a very early diagnosis of leukemia does not increase the patient’s chances of a complete recovery. In this group of patients, allogeneic (from a foreign person) bone marrow transplantation is not performed.
In addition, about 10 percent. people develop diabetes.
Treatment options
Unfortunately, no effective treatments for the disease have yet been developed. Treatment is limited to alleviating skin changes that appear, and rehabilitation in the event of contractures. Treatment of neoplastic diseases occurring in this group of patients is extremely difficult.
Tekst: Anna Jarosz