The allied diseases under the NTSAD umbrella include over 50 lysosomal storage diseases and over 50 leukodystrophies. Here is a brief description of a few of the other allied diseases. Please visit the pdf NTSAD Chart of Allied Diseases (28 KB) for a complete listing.
Fabry is an x-linked lysosomal storage disease affecting roughly 1 in 117,000 people. Fabry is caused by the missing enzyme alpha-galactosidase (alpha-GAL) which breaks down globotriaosylceramide (GL-3). Diagnosis is often delayed because of the wide range of symptoms, including problems with the heart, kidneys, skin, brain and gastrointestinal system. Even though Fabry is x-linked (only affects males) some female carriers experiences mild to severe symptoms.
Gaucher is an autosomal recessive lysosomal storage disease affecting approximately 1 in 20,000 people. It occurs in three types: Type I is the most common, does not affect the central nervous system and treatable, Type II and III are more similar to infantile Tay-Sachs causing progressive loss of motor and mental function and always fatal in children. Gaucher is cause by the missing enzyme glucocerebrosidase which breaks down glucocerebroside. Type I symptoms include easy bleeding and bruising, excessive fatigue, anemia, weak bones, bone and joint pain and swollen belly due to enlarged spleen and liver.
Niemann-Pick disease refers to a group of diseases called Type A, B and C. Each type involves different organs and may or may not involve the central nervous system, onset of symptoms vary from infancy to adulthood. Types A and B are characterized by deficient levels of the enzyme acid sphingomyelinase (ASM). There are approximately 1,200 cases of Type A and B worldwide. Type C is very different than Type A or B. It is characterized by inability to properly metabolize cholesterol and other lipids. There are about 500 known cases worldwide but the incidence is believed to be higher due to challenges diagnosing Type C.
Pelizaeus-Merzbacher is an x-linked leukodystrophy. The incidence is unknown. It is caused by mutations in the gene for the proteolipid protein (PLP). Symptoms usually begin in infancy with involuntary oscillatory movements of the eyes called nystagmus. Other symptoms include labored breathing, lack of muscle tone, stiffness, motor and intellectual milestones delayed. Even though Pelizaeus-Merzbacher is x-linked (only affects males) some female carriers experiences mild to severe symptoms.
Pompe is an autosomal recessive lysosomal storage disease. The incidence is estimated to be 1 in 40,000 births. It is characterized by deficient levels of the enzyme alpha-glucosidase (GAA). Onset of symptoms varies from infancy to adulthood. Babies with early onset experience feeding problems, poor weight gain, muscle weakness and enlarged heart. Symptoms of juvenile and adult forms of Pompe include muscle weakness progressing to breathing problems and cardiac involvement.