What Is Austin-Type Childhood Brain Sulfur Grease Disease
Austin-type cerebral glucosinolate in infants, also known as Austin-type metachromatic leukodystrophy, is a combined disease of cerebral glucosinolate and mucopolysaccharidosis. It is characterized by a mild Hurler syndrome face, multiple bone dysplasia, severe neurological symptoms and marked mental retardation.
What Is The Etiological Factor Of Austin-Type Infantile Cerebral Glucosuria
Genetic defects and a lack of galactosyl-3-sulfate sphingosine sulfatase (cerebrosidase) in our patient were the main causes of this disease.
The basic biochemical defect of this disease is a deficiency of galactosyl-3-sulfate acyl sphingosine sulfatase (cerebrosidase), an aryl sulfatase that has three isozymes, the aryl sulfatases A, B, and C. The gene is located at 22q13. Normally, cerebroside sulfatase catalyzes the desulfurization of galactosyl -3- yl-sphingosine sulfate, lactites, and galactosyl-sphingosine sulfate. Since patients with this disease lack cerebroside sulfatase, the above glycosides are not completely decomposed and can cause diseases due to excessive deposition in the brain.
The pathological changes of this disease are most obvious in the white matter of central nervous system and peripheral nerves, and it can also occur in other internal organs and tissues. Some neurons in the brain tissue were lost, and the astrocytes proliferated. There was microglia reaction in the deeper cortex, and the structure of cortical cells was still preserved. The white matter showed significant loss of neurophospholipid, while the "U" shaped nerve fibers were relatively intact, with a decrease in the number of oligodendrocytes, and deposition of substances in the remaining oligodendrocytes and perivascular macrophages. Cytoplasmic inclusion bodies containing metachromatic substances were observed in the cerebellar dentate nucleus, hypothalamus, thalamus, basal ganglia, pons, spinal cord anterior horn cells, spinal nerve root ganglion cells and retinal ganglion cells. Under a polarized light microscope, the metachromatic substance was yellow and green, and this substance was positive for PAS staining as well as for Sudan Black staining. Under electron microscope, intracellular inclusion bodies were hydrophilic, and most of them were located in lysosomes. Inclusions varied in size (> 1μm) and most consisted of concentric or horizontally stratified structures within a transparent matrix, each 6-8nm thick. Another type of inclusion body consists of an amorphous material surrounded by a thin film (3-4nm) produced by the stroma. There are large spherical or round granular materials outside the cells, which are metachromatic under the microscope.
The pathological changes in the optic nerve and peripheral nerves were segmental demyelination with deposition of metachromatic substances in Schwann cells. Under electron microscopy, the substance is pleomorphic and consists of "zebra bodies". Metachromatic deposits can also be present in renal tubular and bile duct epithelial cells, endocrine gland cells, liver parenchyma cells, and Kupffer cells.
What Symptom Does Austin-Type Infantile Cerebral Glucosuria Have
Clinical symptoms began from 9 months to 2 years of age. The earliest manifestations are behavioral abnormalities, agitation, ataxia, uncoordinated movements, or gait abnormalities, and in most cases hypotonia and occasionally spastic paraplegia. After the lesion lasts for one year, the child cannot stand and the reaction is slow and more obvious, and the child may have language disorder, increased muscle tension (more obvious for lower limbs), weakened or absent deep reflex, further aggravation of ataxia, and intermittent limb pain, etc. By the age of 3 to 4 years, the child is bedridden, develops quadriparesis, and may develop nystagmus, cerebellar lesion signs. Convulsions, optic atrophy and slow reaction are more obvious. Examination of the fundus of the eye can reveal a grayish discoloration of the macula which can lead to blindness later on. In addition to nervous system symptoms, there may be multiple skeletal malformations caused by bone dysplasia and mild Hurler syndrome features in the face, etc.
The diagnosis of this disease is based on clinical symptoms, mainly clinical manifestations of the nervous system, as well as laboratory findings.
How To Check Whether Suffering From Austin Type Infantile Cerebral Glucosuria
Heparan sulfate in urine increased. There were metachromatic inclusion bodies of leukocytes in the peripheral blood. Biochemical analysis of cell inclusion bodies in brain or liver tissues showed that gangliosides were increased, mainly GM2 and GM3 gangliosides, and heparan sulfate was also increased.
X-Ray Examination: The X-ray manifestation was similar to that of mucopolysaccharidosis type I, but the change degree was milder.
How To Prevent Austin Type Infantile Cerebral Glucosuria
To improve the quality of the population, to carry out marriage and maternity guidance, and strive to reduce the incidence of genetic diseases in the population. For individuals, effective preventive measures must be taken to avoid the birth of offspring with genetic diseases and the occurrence of genetic variations. General measures taken include pre-marital examination, genetic counseling, prenatal examination and early treatment of genetic diseases.
How To Treat Austin Type Infantile Cerebral Glucosuria
Treatment: No specific therapy, mainly symptomatic treatment.
Prognosis: The prognosis is poor, and most patients die within the age of 4–6 years old.
How To Identify Austin Type Infantile Cerebral Glucosuria
The differential diagnosis from several other mucositis should be noticed.
What Are The Complications Of Austin Type Infantile Cerebral Glucosuria
The disease can be complicated with nystagmus, cerebellar lesion signs, convulsions, optic nerve atrophy and blindness, and skeletal deformity ataxia caused by multiple bone dysplasia, and spastic paraplegia occasionally.