Retinoblastoma (RB) is a malignant tumor of the retina that occurs in children, usually before the age of five years. RB is due to mutations of the RB1 gene (chromosomal locus 13q14.1-q14.2). Althogh RB is categorized as an autosomal dominant trait, it can occure by chance.
Niemann-Pick disease, type C (NPC) is a lipid storage disease that can present in infants, children, or adults. Toxic byproducts build up in the body causing liver disease and neurological problems from trouble walking to dementia to seizures. NPC is inherited in an autosomal recessive manner and about one in 90 individuals of Eastern European Jewish background is a carrier. Two genes NPC1 and NPC2 were identified by 2003.