Morkio's disease

Description:

Morkio's disease (it is described by the Uruguayan pediatrician of L. Morquio, 1867-1935) belongs to mukopolisakharidoza (the IV type), that is to group of the hereditary diseases of connecting fabric caused by disturbance of exchange of glikozaminoglikan (acid mucopolysaccharides) as a result of genetically caused inferiority of the enzymes participating in their splitting and which it is inherited on autosomal recessively type. At mukopolisakharidoza the system of the lysosomic enzymes participating in a catabolism of glikozaminoglikan is surprised. Owing to enzymatic insufficiency the last collect in a large number in bodies and fabrics therefore mukopolisakharidoza carry to accumulation diseases. The functional condition of various bodies and systems is as a result broken. As glikozaminoglikana are a part of connecting fabric, one of the leading manifestations of a mukopolisakharidoz is systemic lesion of a skeleton, a delay of physical development.

Reasons of fear of Morkio:

Morkio's disease is transmitted on autosomal recessively type. Frequency is up to 1: 40 000. Children are born without symptoms of a disease. The first symptoms appear at the age of 1-3 years, and by 7-8 years the clinical picture is already completely expressed.

Deficiental enzyme – галакто - beta sulfate-sulphatase (type A); beta galactosidase (type B).

Symptoms of a disease of Morkio:

The disease is characterized by dwarfism (growth of the adult patient about 100 cm), a disproportionate constitution (rather short trunk, a nanocephalia, a short neck), rugged features and considerable deformations of a skeleton, especially a thorax (chicken, barrel-shaped, kileobrazny), a kyphosis or scoliosis of chest and lumbar departments of a backbone. Food is lowered. Rigidity in joints and at the same time relaxation of the sumochno-copular device in small joints, a neck is shortened, a hypoplasia of shoots of I and II cervical vertebrae. In case of a compression of a spinal cord in addition to a hypomyotonia defeat of pyramidal system is noted, development of a paraplegia, breath paralysis is possible. There are contractures in elbow, shoulder, knee joints, valgus deformation of the lower extremities, flat-footedness is noted. The intelligence is not broken, there is no gepatosplenomegaliya. The person is usual, the skull sizes without changes. Skin is thickened, its turgor and elasticity are reduced. Often umbilical and inguinal hernias, a divarication of recti come to light. Unsharply expressed opacification of corneas is sometimes noted. Decrease in hearing is quite often noted. Almost at all patients who lived up to 20 years deafness develops. In the late time of a disease disturbances of cardiovascular system, thinning of teeth appear. Besides at patients the cardiopathy and a myopathy can be observed. As a rule, muscle strength is reduced. With urine a large number of a keratansulfat is allocated. In most cases the expressed clinical manifestations the lethal outcome comes up to 20 years owing to the cardiopulmonary insufficiency developing against the background of intercurrent diseases. Sudden death as a result of the shift of an atlantooccipital joint and damage of a brainstem is possible.

Diagnosis:

Radiological characteristic changes in a rachis are visible: flattening of bodies of vertebrae, decrease in height of their front departments, delay in development of apophyses, especially in the XII chest and the I lumbar vertebrae. Kyphoscoliosis. In all departments the platyspondylia - flattening and expansion of bodies of vertebrae is noted, than characteristic shortening of a trunk and unusually short neck speaks. An epiphysis of long tubular bones is underdeveloped. Ossification of metaphyses also irregular and later. Brushes are shortened, wide fingers are thickened, with conical shape of an epiphysis. Bones of a forearm are shortened; the ulna does not reach a radiocarpal joint, dislocation of its head in an elbow joint is noted; epiphysis of triangular shape. A distal epiphysis of bones of a shin is slanted, feet are deformed. Pelvic bones change: acetabular hollows flat and wide, their roof is slanted, wings of ileal bones of irregular shape; contours of all bones uneven; heads of femurs are flattened. The fungoid head of a femur is implemented into a profound acetabular hollow. the neck of a hip is shortened. damage of joints bilateral therefore basin diameter decreases. Osteoarthrites, especially in hip joints are frequent. The valgus deformation of the lower extremities increasing with age is characteristic. Flattening of eopifiz of a femoral and tibial bone, smoothing of intercondyloid hillocks are followed by specific deformation of knee joints. Damage of an ankle joint causes the wrong installation of foot.
The diagnosis is made on the basis of characteristic external displays of a disease. As biochemical screening apply excretion researches with urine of metabolites of mucopolysaccharides and activities of lizosomalny enzymes in leukocytes of blood and culture of fibroblasts of skin. The diagnosis can be helped by the family anamnesis. At diagnosis it must be kept in mind that various biochemical defects can lead to similar clinical symptoms and vice versa, the lack of one and a togozha of enzyme can have different phenotypical manifestations. The diagnosis is confirmed by assessment of activity of lizosomalny enzymes in plasma or leukocytes of blood, culture of fibroblasts of skin and, in some cases, research DNA. The prenatal diagnosis is possible.

Treatment of a disease of Morkio:

As well as at other lizosomalny diseases of accumulation, effective treatment of neurologic complications of mukopolisakharidoz is not present. At development of hydrocephaly, a prelum of a spinal cord, instability of an atlanto-axial joint and tunnel neuropathies surgical intervention is shown. A perspective method of treatment of mukopolisakharidoz – gene therapy. The symptomatic treatment is very important.