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Galactosialidosis is one of seven identified Glycoprotein storage diseases. The disorder is caused by a lack of an enzyme called Protective Protein/Cathepsin A (PPCA). This enzyme works with two other enzymes, beta-Galactosidase and Neuraminidase, to break down long sugar chains in the lysosome. However, PPCA also protects beta-Galactosidase and Neuraminidase from being broken down in the lysosomes and therefore, those stricken with Galactosialidosis are deficient in these enzymes as well. Individuals with Galactosialidosis show the typical physical characteristics shared by many of the lysosomal storage diseases. These include coarse facial features, abnormal bone formation and cherry red spots seen on ophthalmology evaluation. There are three different types of Galactosialidosis. They are characterized by the age of onset and type of physical and mental manifestations. Type I is called the early infantile type of Galactosialidosis, and onset is typically between birth and three months of age. Individuals with this type of Galactosialidosis present with hydrops, edema, and fluid accumulation in different parts of the body. Occasionally, as with many LSDs, enlargement of the liver and/or spleen is present. Infants with Galactosialidosis may have skeletal changes, especially involving the spine. Cognitive and motor delay is also present. Echocardiogram may show cardiomegaly (enlarged heart), kidney function can be impaired, and there may be increased protein detected in the urine. Cardiac and/or renal failure is typically the cause of death in individuals with early infantile Galactosialidosis, usually within the first year of life. The second type of Galactosialidosis is called the late infantile type and onset is within the first few months of life. Individuals usually present with coarse facial features, enlargement of the spleen and liver, and dysostosis multiplex (defective bone formation). Bony changes are especially noticeable in the spine. Cherry red spots and/or corneal clouding may be present. Neurological problems such as ataxia (inability to coordinate voluntary muscular movements) or seizures are rarely seen in the late infantile type of Galactosialidosis. Mental retardation may be present and is generally mild. Cardiac findings usually involve thickened valves within the heart. Additionally, hearing loss may occur. The majority of individuals with Galactosialidosis have the third type, the juvenile/adult type of Galactosialidosis. The juvenile/adult type has a wide range of severity of features and age of onset. The average age that symptoms appear is around 16 years, but may present initially as late as the 3rd or 4th decade. Additionally, individuals with this type of Galactosialidosis are predominantly of Japanese origin. Common findings include coarse facial features and spinal changes. Neurological problems such as ataxia, seizures, and deteriorating mental abilities may also be present. Typical eye abnormalities include cherry red spots, corneal clouding, and vision loss. Angiokeratomas (superficial blood vessel dilations over which wart-like growths occur) are typical for the juvenile/adult form but are not present in the early or late infantile forms of Galactosialidosis. |