However, the disease is now divided into two distinct units: the first being acid sphingomyelinase-deficient Niemann-Pick disease which is caused by mutations in the SMPD1 gene which also includes type A and B within it (Vanier, 2013). The second is Niemann-Pick disease type C as well as type D which result from mutations NPC1 or NPC2 gene (Vanier, 2013). Furthermore, both units have an ‘autosomal recessive inheritance and are lysosomal lipid storage disorders, with viscera; (type B) or neurovisceral manifestations (Vanier, 2013). 

Type A and B are lysosomal storage disorders that occur due to the acid sphingomyelinase activity being poor as well as the amassing of sphingomyelin (Schuchman, n.d). The pathologic symbol of types A and B is the histochemical characteristic lipid-laden foam cell (Schuchman, n.d).  They are both inherited as autosomal recessive traits, however, according to Schuchman, type A is more lethal than type B; it is a fatal disorder related to infants which is characterized by hepatosplenomegaly (failure to thrive). Furthermore, it is characterized by the ‘[rapid] progressive neurodegenerative course’ which results in death by the age of 2 to 3 years. 

Type B is a ‘phenotypically variable disorder’ (hepatosplenomegaly) that is diagnosed more during childhood (schuchman, n.d). Majority of the type B patients have little to no neurologic association and live on to adulthood (shuchman, n.d). In the more severe strain of this type of Niemann-Pick disease, the patients have ‘progressive pulmonary infiltration’ which then causes serious disease complications (schuchman, n.d).  

Type C of the Niemann-Pick disease is a ‘neurovisceral atypical lysosomal lipid storage disorder’ that does not have large incidence in live births; it is caused by NPC1 (95% of the time) and NPC2 mutations (Vanier, 2010). The visceral, liver & spleen, and the neurological manifestations emanate at disparate times along with the fact that their courses are independent of each other (Vanier, 2010). The disease includes disorders that are categorized by distinct intracellular carriage of endocytosed cholesterol with desolation of cholesterol that has not been esterified in lysosomes and late endosomes (Vanier, 2010). It is an autosomal recessive inherited as well as panethnic disease that is not restricted to a specific age group as it affects neonatal patients all the way to adults (Vanier, 2010).

Its primary function is to regulate cellular energy homeostasis, with triglycerides being the greatest form of energy storage, as well as lipid metabolism. They also manage the hydrolysis and storage of the lipids. In addition, they play a role in membrane formation as well as its maintenance using the stored cholesterol and acyl-glycerols.  Some studies also suggest that the lipid droplets may facilitate the transportation of lipids amongst other organelles in the cell as well as protect some proteins from detrimental interactions with other organelles.

Subsequently, an accumulation of excess lipids in the depots lead to metabolic disorders such as diabetes mellitus and obesity. It also causes the Niemann-Pick disease, whereby the build-up of the lipids causes cells to be defective and die leading to an impaired function of tissues and organs.

According to Erickson Gabby, the symptoms for the different types of Niemann-Pick diseases differ.

 

·       Abdominal Swelling from 3 to 6 months

·       Red spot on the retina

·       Difficulties feeding

·       Loss of early motor skills (worsens with time)

 

·       Low blood platelet count

·       Mental retardation

·       Poor coordination

·       Peripheral nerve problems

 

·       Hypertrophy of the Spleen and Liver.

·       Jaundice

·       Seizures

·       Slurred speech

Treatments

The treatments vary according to the type of the disease. Currenlty, there is no effective treatment for the Type A form of Niemann-Pick, (Hurst, 2016).

 

The current treatments for Type B include bone marrow transplants and there is ongoing research into enzyme replacement treatments and gene therapy.

 

The nervous system symptoms of Type C are treated with Miglustat, an enzyme inhibitor that functions by inhibiting the production of fatty substances (cholesterol) so that less build up in the body. 

Further treatments focus on treating specific symptoms of the disease, rather than its overall presentation, (Hurst, 2016).
  

Type C

-Diagnosed with a skin biopsy stained with a special stain. Once a sample is taken, laboratory scientists analyze how the skin cells grow, as well as how they move and store cholesterol.
-DNA testing may also be used determine the togenes that cause type C.