Our genetic code is so complex that almost any serious damage can cause a chain reaction and affect a person not from the best side. Scientists are constantly discovering new diseases, but, in their own words, ninety percent of the genome remains unexplored.
Description
Larsen syndrome (ICD 10 - code M89) is a rare genetic disease that has a wide range of phenotypic manifestations. The most characteristic signs are dislocations and subluxations of large joints, the presence of malformations of the bones of the facial skull and problems with the functions of the limbs. Minor manifestations include scoliosis, clubfoot, short stature, and breathing difficulties.
Larsen syndrome is caused by point mutations that can occur spontaneously or be inherited in an autosomal dominant manner. Changes in the FLNB gene are associated with a whole group of diseases manifested by disorders in the skeletal system. Specific manifestations may vary even among relatives.
Reasons
What must happen in the developing organism for Larsen's syndrome to occur? The causes of this disease are still hidden in scientific twilight. It is only known that it is characterized by autosomal dominant inheritance. That is, just one copy of the altered gene will be enough to pass the pathology to your children, and maybe even grandchildren. The gene can be obtained from parents (from both or from one) or be the result of a spontaneous mutation. The risk of inheriting this disease is 50/50, regardless of the sex of the child and the number of pregnancies.
The altered gene is located on the short arm of the third chromosome. If desired, researchers can accurately indicate the place where the hereditary information has undergone changes. Normally, this gene encodes a protein known in scientific circles as filamin B. It plays a significant role in the development of the cytoskeleton. Mutations lead to the fact that the protein ceases to perform the functions assigned to it, and the cells of the body suffer from this.
People with this syndrome may have mosaicism. That is, the severity and number of manifestations of the disease directly depend on how many cells were affected. Some people may not even be aware that they have a defect in this gene.
Epidemiology
Larsen's syndrome develops with the same frequency in both men and women. According to very rough estimates, this disease occurs in one newborn out of a hundred thousand. This, fortunately, is a rarity. Estimates are considered unreliable,because there are certain difficulties in identifying this syndrome.
For the first time in the medical literature, the disease was described in the middle of the twentieth century. Lauren Larsen et al found and documented six cases of the syndrome in children.
Symptoms
Larsen syndrome, as mentioned above, can manifest itself in different ways even between close relatives. The most characteristic signs of the disease are changes in the bones of the face. These include: a wide low bridge of the nose and a wide forehead, a flat face, the presence of a cleft of the upper lip or hard palate. In addition, children have dislocations of large joints (femoral, knee, elbow) and shoulder subluxations.
The fingers of such people are short, wide, with weak loose joints. Additional bones may be present in the wrists, which fuse with age and interfere with the biomechanics of movement. Some people experience the rare phenomenon of tracheomalacia (or softening of the cartilage of the trachea).
Diagnosis
The diagnosis of "Larsen's syndrome" is made only after a complete examination of the patient, a thorough study of his medical history and the presence of characteristic x-ray symptoms. In addition, a full-fledged radiographic examination can also reveal concomitant anomalies in the development of the skeleton, which are indirectly related to the disease.
Ultrasound diagnosis even in the prenatal period can reveal Larsen's syndrome. Photo of boneformations for a well-trained specialist, ultrasound can be the starting point for the search for genetic abnormalities of the fetus. Since at first glance it is impossible to say what kind of disease led to the pathology of the facial skull and bones of the limbs, the expectant mother is recommended to do an amniocentesis and conduct a genetic examination to search for a mutation in the third chromosome.
If the disease is confirmed, but the spouses have decided to continue the pregnancy, then the expectant mother is recommended to perform a caesarean section so as not to damage the baby's bones in the process of passing it through the woman's pelvis during natural childbirth.
Treatment
Therapeutic measures are not aimed at eliminating the disease, but at reducing clinical manifestations. This is done by pediatricians, orthopedists, specialists in maxillofacial surgery and genetics. After assessing the initial condition of the child and assessing all risks, they can begin to correct existing violations.
The most gentle option for treating Larsen's syndrome is massage. It is needed to strengthen the muscles and ligaments that hold the joints together, as well as to improve back support and spinal alignment. But before proceeding with therapeutic methods, a number of operations will be required. They are necessary to correct gross skeletal deformities or deformities, to stabilize the vertebrae. Tracheomalacia requires intubation and then a breathing tube (permanently) to keep the upper airway open.
Cure itdisease is a long process that can take years. As the child grows older, the load on the bones increases, and he may again need physical rehabilitation, exercise therapy, and maybe even surgery.
