How is NPD Transmitted?

All types of Niemann-Pick are autosomal recessive. This means that children with Niemann-Pick disease have two copies of the abnormal gene.

Each parent carries one copy of the abnormal gene without having any signs of the disease themselves. The parents are carriers or heterozygotes. Siblings of the parents may also be carriers of the abnormal gene.

When both parents are carriers, there is:

-> a 1 in 4 chance that a child will have the disease
-> a 1 in 2 chance that a child will be a carrier
-> a 1 in 4 chance that a child will not have the disease and will not be a carrier

Carrier detection testing for all families is not yet reliable.

The mutations for Types A and B have been extensively studied, particularly among the Ashkenazi Jewish population, and DNA tests for these forms of Niemann-Pick are available. Antenatal diagnosis (diagnosis in the fetus) of Niemann-Pick is available in a limited number of centers.

Dr. Wenda Greer of Dalhousie University has identified the genetic mutation related to Type D (now called the Nova Scotia variation of NPC). Carrier detection tests can be done for this mutation.

Carrier detection is possible for other families only after their specific mutation is identified. See the Diagnosis page for more details about genetic testing.