Larsen's Syndrome: Causes, Symptoms, Treatment

Our genetic code is so complex that almost any serious breakdown can cause a chain reaction and affect the person not from the best side. Scientists are constantly finding new diseases, but, in their own words, the ninety percent of the gene remains unexplored.

Description

Larsen's 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 defects in the development of the bones of the facial skull and problems with the functions of the extremities. Secondary manifestations include scoliosis, clubfoot, low growth and difficulty with breathing.

Larsen's syndrome is caused by point mutations that can occur both spontaneously and be inherited in an autosomal dominant manner. With the changes in the FLNB gene, a whole group of diseases, manifested by disorders in the skeletal system, is associated. Specific manifestations can be different even among relatives.

Causes

What should happen in the developing organism so that Larsen's syndrome arose? The causes of this disease are still hidden in the scientific half-light. It is only known that for him, autosomal dominant inheritance is characteristic. That is, only one copy of the altered gene will be enough to pass on the pathology to their children, and maybe even to their grandchildren. A 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 in the short arm of the third chromosome. If desired, researchers can pinpoint where the hereditary information has undergone changes. Normally, this gene encodes a protein known in the scientific community as phylamine 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 organism 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 suspect that they have a defect in this gene.

Epidemiology

Larsen's syndrome with the same frequency develops in both men and women. By very rough estimates, this disease occurs in a newborn of a hundred thousand. This is, fortunately, a great 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 and co-authors found and documented six cases of the syndrome in children.

Symptoms

Larsen's syndrome, as mentioned above, can manifest itself in different ways, even between close relatives. The most characteristic signs of the disease are the changes in the bones of the face. These include: a broad low nose and broad forehead, a flat face, the presence of an unbuttoned upper lip or hard palate. In addition, children have dislocations of large joints (femoral, knee, elbow) and subluxation of the shoulder.

The fingers of such people are short, wide, with weak loose joints. In the wrists, there may be additional bones that, with age, merge and disrupt the biomechanics of the movements. Some people have such a rare phenomenon as tracheomalacia (or softening of the cartilage of the trachea).

Diagnostics

The diagnosis of "Larsen's syndrome" is made only after a complete examination of the patient, a thorough examination of his medical history and the presence of characteristic radiographic symptoms. In addition, a full radiographic examination can reveal and accompanying anomalies in the development of the skeleton, which have an indirect relationship to the disease.

Ultrasound diagnosis in the prenatal period can reveal Larsen's syndrome. Photo of bone formations for a well-trained specialist of ultrasound may be the starting point for the search for genetic abnormalities of the fetus. Since at first glance it is impossible to say which disease led to the pathology of the facial skull and limb bones, the future mother is recommended to make an amniocentesis and conduct a genetic examination to find a mutation in the third chromosome.

If the disease is confirmed, but the couple decided to continue their pregnancy, the expectant mother is advised to have a caesarean section so as not to damage the baby's bones as she passes through the woman's pelvis during natural childbirth.

Treatment

Therapeutic measures are not aimed at eliminating the disease, but on reducing clinical manifestations. This involved pediatricians, orthopedists, specialists in maxillofacial surgery and genetics. After assessing the child's initial condition and assessing all risks, they can begin to correct the existing violations.

The most gentle option, which treats Larsen's syndrome, is massage. It is necessary to strengthen the muscles and ligaments that hold the joints, and also to improve the maintenance of the back and straighten the spine. But before proceeding to therapeutic methods, a number of operations will be required. They are necessary for correcting gross deformations of the skeleton or deformities, stabilizing the vertebrae. When tracheoclimation requires intubation, and then the installation of a respiratory tube (on an ongoing basis), which will maintain patency of the upper respiratory tract.

Treatment of this disease is a long process, which can last for years. As the child grows older, the load on the bones increases, and he may again need physical rehabilitation, physiotherapy exercises, and maybe even surgical intervention.