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Alpha-N-acetylgalactosaminidase deficiency type 3
Disease definition
A rare clinically heterogeneous type of NAGA deficiency with developmental, neurologic and psychiatric manifestations presenting at an intermediate age.
ORPHA:79281
Classification level: Subtype of disorderSummary
Epidemiology
Prevalence of this disorder is not known but less than 20 cases have been reported to date for NAGA deficiency
Clinical description
A very wide spectrum of signs, with a juvenile onset, has been described including asymptomatic patients at the time of diagnosis. Manifestations seen in clinically overt cases may include epilepsy of variable severity, psychomotor retardation, intellectual impairment, autism, strabismus and cataract.
Etiology
Compound heterozygous or homozygous mutations of the alpha-N-acetylgalactosaminidase gene (NAGA; 22q13.2) have been reported in affected patients but also occasionally in their healthy siblings. These mutations lead to the dysfunction, instability and rapid degradation of the lysosomal protein NAGA.
Genetic counseling
Transmission is autosomal recessive and genetic counseling is possible.
A summary on this disease is available in Deutsch (2013) Español (2013) Italiano (2013) Nederlands (2013) Polski (2013, pdf)
Additional information