Barbara Burton, MD, Attending Physician, Genetics, Birth Defects & Metabolism, Ann & Robert H. Lurie Children’s Hospital of Chicago, discusses the diagnostic challenges often faced by alpha mannosidosis patients.
Alpha mannosidosis is a multisystemic, mucopolysaccharidosis (MPS) disorder caused by a deficiency in the enzyme alpha-D-mannosidase. This enzyme is essential for metabolizing certain glycoproteins, and a deficiency allows these glycoproteins to abnormally accumulate in and damage various tissues and organs.
The symptoms and severity of alpha mannosidosis are highly variable. Symptoms may include distinctive facial features (e.g., prominent forehead and jaw, and a flattened nose), skeletal abnormalities, hearing loss, intellectual disability, and dysfunction of the immune system. Alpha-mannosidosis is caused by an autosomal recessive mutation of the MAN2B1 gene.
As Dr. Burton explains, a diagnosis of alpha mannosidosis is reached by measuring alpha-D-mannosidase levels or through genetic testing. Dr. Burton urges physicians and patients to make sure the enzyme or genes being tested include alpha-D-mannosidase or the MAN2B1 gene, respectively.
According to Dr. Burton, patients with alpha mannosidosis may be seen by 6 different physicians over the course of many years before receiving a proper diagnosis. Often, this is due to physicians being unfamiliar with the disease. Additionally, many of the first signs and symptoms of alpha mannosidosis – such as developmental delay – are non-specific.
To reduce diagnosis times, for this and other rare diseases, Dr. Burton suggests symptoms be taken into consideration as a group. For example, if a patient is presenting with developmental delay, frequent infections, immunoglobulin deficiency, and hearing loss, this should provoke a physician to look into conditions (e.g., alpha mannosidosis) that present with this cluster of symptoms.
To learn more about alpha mannosidosis and other lysosomal storage diseases, visit checkrare.com/diseases/lysosomal-storage-disorders/
