Hypoplasia and deformity of carpal bones and rod-like changes of metacarpal bones

Introduction Carpal dysplasia and rodar changes in the metacarpal bone are seen in the type of mucopolysaccharidosis type VI, which is also known as Maroteaux-Lamy syndrome, multiple dystrophic dwarfism. It is an autosomal recessive hereditary disease. 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 at 5q12 to q13 and may have 2 alleles.

Cause

Causes of carpal dysplasia and rodar changes in the metacarpal:

The disease is autosomal recessive. 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 at 5q12 to q13 and may have 2 alleles. In this type of human body, due to the insufficient activity of the enzyme, chondroitin-4-sulfate and dermatan sulfate can be deposited in various tissue cells to cause disease.

an examination

Related inspection

Bone imaging and joint MRI examination

Diagnosis of carpal dysplasia and rodar changes in the metacarpal:

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.

Laboratory tests: Excessive dermatan sulfate in the urine. There are many distinct and heterogeneous particles in neutrophils and lymphocytes.

Other auxiliary examinations: X-ray examination: the same type of mucopolysaccharidosis. Changes in limbs, spine, and pelvis are common. In addition, there are head changes and are characteristic.

Differential diagnosis

Differential diagnosis of carpal dysplasia and rodar changes in the metacarpal:

Mucopolysaccharidosis type I: This symptom of visceral lesions, skeletal deformities and mental disorders is very serious. When the child is born, his appearance is still normal, but he can quickly show that the movement and mental development are backward to 1 to 2 years old, which can clearly reveal the characteristics of the disease. The child's appearance gradually became rough, the nose was wide and flat, the eye distance was wide, the lip was thick, the tongue was large, and the ear was low and the teeth were small and sparse. The skin has thicker hair and longer eyebrows. The head circumference increases the sagittal suture and the anterior and posterior diameter increases (scapular head), occasionally the hydrocephalus of the hydrocephalus is severely deformed, the fingers are short and short, and the spine is bent backward. The joints gradually contracted and straightened, and the fingers were fixed in the semi-flexion position, and the claws were short.

1. The nervous system: mainly mental retardation, it is obvious after 1 year old, the action is stupid, and the language development is slow to respond to the surrounding environment. The degree of mental retardation is related to the concentration of mucopolysaccharide in the cerebrospinal fluid. There are not many authors with horror. Other signs of the nervous system, such as reduced or hyperactive sputum reflexes, pathological reflexes of spastic paralysis, etc. may also appear

2. Circulatory system: Cardiovascular symptoms are obvious, including cardiac hypertrophy, pulmonary hypertension, and systolic murmurs of the left sternal or apical apex caused by valvular disease. A wide infarction of the coronary arteries can cause sudden death.

3. Respiratory system: Recurrent respiratory infections and ventilatory disorders. Increased nasopharyngeal secretions, tonsil and adenoid proliferation of craniofacial bone deformities, can cause narrowing of the nasopharyngeal cavity, breathing difficulties, mouth breathing, voice. If the thoracic deformity is accompanied by bronchial cartilage deformity, the breathing difficulty is more serious, and it is easy to cause pneumonia and bronchitis.

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