mucopolysaccharidosis type VI
Introduction
Introduction to Mucopolysaccharidosis Type VI Mucopolysaccharidosis type VI is also known as Maroteaux-Lamy syndrome, multiple dystrophic dwarfism, and is also an autosomal recessive hereditary disease characterized by short stature, corneal opacity, but normal intelligence. This type of mucopolysaccharidosis was first discovered by Maroteaux (1963) and is an independent disease different from other types of mucopolysaccharidosis. basic knowledge Sickness ratio: 0.0002%-0.0005% Susceptible people: no special people Mode of infection: non-infectious Complications: hydrocephalus hereditary spastic paraplegia heart failure umbilical hernia inguinal hernia
Cause
Mucopolysaccharidosis type VI etiology
(1) Causes of the disease
The disease is autosomal recessive.
(two) pathogenesis
The basic biochemical defect of this disease is the reduction of N-acetylgalactosamine-4-sulfatase activity, which can hydrolyze the sulfuric acid in N-acetylgalactosamine-sulfate, which occurs in chondroitin-4- Sulfuric acid, also occurs in dermatan sulfate, the gene is located in 5q12 ~ q13, there may be 2 alleles, this type of human body due to the lack of activity of this enzyme, it can make chondroitin-4-sulfate and dermatan sulfate It is deposited in various tissue cells and causes disease.
Prevention
Mucopolysaccharidosis type VI prevention
Glycogen accumulation disease is a group of children with disorders of hereditary glycogen metabolism. It is characterized by excessive accumulation of glycogen in the body tissue and difficulty in decomposition. It is rarely a metabolic disorder of glycogen, resulting in less glycogen storage in the body. The original cumulative disease is not a disease, but a group of diseases. There are 12 kinds of diseases currently identified. The clinical features are characterized by hypoglycemia. The organs involved are mainly liver, kidney and skeletal muscles. Chromosomal recessive inheritance, no gender differences, mostly in childhood, some patients to adults, the disease no longer develops, can maintain general health.
The patients are mainly due to the lack of certain enzymes that break down glycogen, such as glucose-6-phosphatase, -1,4 glucose chymase, phosphofructokinase, hepatic phosphorylation kinase and the like.
Parents of many patients marry close relatives, avoiding close relatives marriage is an important part of preventing this disease. Once glycogen accumulation is found, it is mainly to prevent and treat hypoglycemia, a small amount of meals, limit fat and total calories, limit physical activity, serum lactic acid The highest, should take sodium bicarbonate to prevent acidosis, corticosteroids, adrenaline, glucagon, etc. can help control hypoglycemia.
Complication
Mucopolysaccharidosis type VI complications Complications, hydrocephalus, hereditary spastic paraplegia, heart failure, umbilical hernia, inguinal hernia
The severity of this disease can be complicated by hydrocephalus and spastic paraplegia, and some can occur heart failure, umbilical hernia and inguinal hernia, liver, spleen mild to moderate swelling.
Symptom
Mucopolysaccharidosis type VI symptoms common symptoms short neck axillary dislocation abnormal short meningeal thickening hydrocephalus heart failure carpal tunnel syndrome paraplegia
According to the severity of clinical symptoms, this type of mucopolysaccharidosis can be divided into severe (MPSVI-A) and light (MPSVI-B), and the severity is more than 2 to 3 years old, often with limited joint movement. Hernia, limbs contracture, rough appearance, short neck, short stature, due to the slow development of the trunk and limbs, it can appear imbalance in body size, the appearance is not as thick as the mucopolysaccharid storage disease type I and type II, the head is slightly larger, two eyes The spacing is too wide, and some cases can also be combined with hydrocephalus. In most cases, there may be different degrees of peripheral corneal opacity and hearing loss. Bell-shaped chest, funnel chest, umbilical hernia and inguinal hernia may also appear in the aortic valve area. Frequently heard murmurs caused by aortic regurgitation, usually liver, spleen mild to moderate swelling, can cause spinal vertebral changes in the spine, pelvis, hands and head, the second cervical dysplasia, can lead to the atlantoaxial Dislocation and meningeal thickening, spinal cord disease or neurological complications, chest and lumbar vertebral body deformation, pelvic dysplasia, this type of patient, like other types of mucopolysaccharidosis, can also occur carpal bone dysplasia, change The metacarpal bone has a rod-like change, and the herringbone seam fusion and odontoid dysplasia can cause neurological complications, such as hydrocephalus and spastic paraplegia. Carpal tunnel syndrome often occurs due to collagen tissue compression, and respiratory infection can occur repeatedly. Some may have heart failure, mild cases have a higher age of onset, skeletal deformities are lighter, and the disease progresses slowly.
Examine
Mucopolysaccharid storage disease type VI examination
There are too many dermatan sulfates in the urine, and there are many obvious metachromatic particles in neutrophils and lymphocytes.
X-ray examination: the same type of mucopolysaccharidosis, with changes in limbs, spine, and pelvis is common, in addition to head changes, and is characteristic.
1. Limbs: The femoral and tibial tubular bones have abnormal bones. In many cases, there are osteophytes and sacral deformities. The long bones of the upper limbs are more obvious than the lower limbs. The short bone changes of the hands and feet vary from person to person, but they are all deformed. The metacarpal bone is rod-shaped, and the carpal bone is underdeveloped or deformed.
2. Spine: The changes in the thoracolumbar vertebrae are obvious. The manifestations include small vertebrae, beak-like or other malformations. There may also be kyphosis. The ribs are paddle-shaped, with the sternum protruding forward to make the chest appear. Funnel-shaped, rib deformation can make the chest a bell.
3. Pelvis: The iliac crest is underdeveloped, deformed, the acetabulum is small, and the femoral condyle is irregular and flattened.
4. Skull: The saddle enlargement is "B" shape, with sclerosing mastoid, dysplasia and herringbone fusion.
Diagnosis
Diagnosis and identification of mucopolysaccharidosis type VI
This type of diagnosis is based on the appearance of typical clinical symptoms. Excessive excretion of dermatan sulfate and leukocytes in the urine produces distinct metachromatic particles (Reilly bodies), and white blood cells or skin or fibroblast cultures show N-acetylgalactosamine- 4-sulfatase deficiency.
The differential diagnosis of this type is the same as type I.
