Classification
In the third edition of the International Classification of Sleep Disorders (ICSD-3), Obstructive Sleep Apnea is classified amongst the Sleep-Related Breathing Disorders and is divided in two categories, namely adult OSA and pediatric OSA. Obstructive Sleep Apnea is differentiated from central sleep apnea (CSA), which is characterized by episodes of reduction or cessation in breathing attributable to decreased effort, rather than upper airway obstruction. The respiratory effort must then be assessed in order to correctly classify the apnea as obstructive given the specificity of the diaphragmatic activity in this condition: the inspiratory effort is continued or increased through the entire episode of absent airflow. When hypopneas are present alongside apneas, the term Obstructive Sleep Apnea-Hypopnea is used and when it is associated with daytime sleepiness and other daytime symptoms, it is called Obstructive Sleep Apnea-Hypopnea Syndrome. To be categorized as obstructive, the hypopnea must meet one or more of the following symptoms: (1) snoring during the event, (2) increased oronasal flow flattening, or (3) thoraco-abdominal paradoxical respiration during the event. If none of them are present during the event, then it is categorized as central hypopnea. Signs and symptoms
Common symptoms of OSA syndrome include unexplained daytime sleepiness, restless sleep, and loud snoring (with periods of silence followed by gasps).
People with type I Gaucher have a defect in the enzyme called glucocerebrosidase (also known as acid β-glucosidase). Glucocerebrosidase is an enzyme, and its function is to convert glucocerebroside (also known as glucosylceramide) into ceramide and glucose. When this enzyme doesnt work, glucocerebroside accumulates, which in turn causes liver and spleen enlargement, changes in the bone marrow and blood, and bone disease. It functions as a competitive and reversible inhibitor of the enzyme  glucosylceramide synthase,  the  initial  enzyme  in  a  series  of  reactions  which  results  in  the  synthesis  of  most glycosphingolipids.Earlier treatments on the market (imiglucerase (approved in 1995), velaglucerase (approved in 2010), taliglucerase alfa (Elelyso) (approved in 2012)) are enzyme replacement therapy - they are functioning versions of the enzyme that doesnt work. Miglustat works differently - it prevents the formation of the substance that builds up when the enzyme doesnt work; this is called substrate reduction therapy. Chemistry
Miglustat is an iminosugar, a synthetic analogue of D-glucose and a white to off-white crystalline solid that has a bitter taste. Society and culture
Legal status
Miglustat has been approved in the EU, Canada, and Japan for treating progressive neurological complications in people with Niemann–Pick disease, type C (NPC). Miglustat has not received approval for this indication outside of these countries and use for this disease, including the US, is off-label.