Written by Harshita Parmar
Edited by Shania Sheth and Jocelyn Wang
There are many genetic disorders that are well known to the common public as we hear them periodically in our day to day lives, whether it be on the news or in our health classes, such as Down Syndrome, Turner Syndrome, and Cystic Fibrosis. The effects of these genetic disorders are well known, from neurological disabilities to motor dysfunction. In this article, we will be discussing a much rare genetic disorder that primarily affects pediatric patients, from infancy to adolescence, but can affect adults the same.
What is Krabbe Disease?
Krabbe disease, also known as globoid cell leukodystrophy, is a rare genetic disorder that causes lipid buildup in various cells and tissues throughout the body to a dangerous extent which can also cause the destruction of brain cells. Globoid cells, which are cells that have more than one nucleus, break down the nerve’s protective myelin coating, causing this disorder to attack the central and peripheral nervous systems. This disease is also categorized as a lysosomal storage disorder, which occurs when the lysosome of the cell does not function properly. In a healthy person, enzymes typically break up the content in lysosomes but if the body does not produce enough amounts of an enzyme, like GALC for example, this causes toxins to build up. This causes toxicity to occur in the brain, especially when GALC is not produced enough, which leads to the process of demyelination, the deterioration of the myelin sheath in the brain. This process interrupts signals sent and received in both the central and peripheral nervous systems, which causes Krabbe disease to progress further.
How is Krabbe disease inherited?
Since this disorder is a genetic disorder, it is also categorized as an autosomal recessive disorder. If both parents happen to be a carrier with a genotype Rr of this gene, there is a 25% chance their child will have this disorder. The possible genotypes of the offspring if the parents both have a genotype of Rr would be RR, Rr, Rr, and rr. From the genotypes of the children, one child would be unaffected, two children would be unaffected but carriers of the gene, and one child would be affected.
What are the symptoms and different types of Krabbe disease?
Although this disease, as it progresses, can eventually attack all bodily systems, some of the symptoms that the affected can experience include muscle weakness, blindness, deafness, hypertonia, and difficulty swallowing, coughing, walking, and even speaking. There are also three different types of Krabbe disease: Early Infantile Krabbe Disease, Later Onset Krabbe Disease, Adolescent and Adult Onset Krabbe Disease.
Early infantile Krabbe disease, like the name suggests, affects children in their first few months of living and is the most severe and is often misunderstood for colic, reflux, and even cerebral palsy. Infants can experience symptoms such as irritability, stiffness, excessive crying, decrease in motor skills, loss of previously achieved milestones, as well as seizures and difficulty feeding. Later onset Krabbe disease affects children from age 6 months to 3 years, and the symptoms for this group of children with the disease are similar to those affected with Early infantile Krabbe disease. For adolescent onset Krabbe disease, there is an initial regression of motor skills at 3 years of age or later. After an initial decline, the disease can progress at a slower rate than infantile onset, over the course of a few years. Adult Onset involves initial loss of vision along with muscle stiffness, muscle pain and difficulty walking.
How is Krabbe disease diagnosed and treated?
Diagnosis for this disease can be done through multiple tests, such as blood test, MRI, nerve conduction study, and even genetic testing. Newborn screenings are conducted in some states which can help ensure the proper diagnosis of the disease through other tests if symptoms are to be found. There is no definite cure for this disease yet, but its symptoms can definitely be treatable. Patients that are diagnosed with this disease before it has progressed too far can have an umbilical cord blood or bone marrow transplant done. In these procedures, stem cells that contain healthy levels of the enzyme GALC are inserted so the disease can’t further progress and worsen, however this treatment is unable to repair damaged myelin. If a child is unable to receive this treatment in a timely manner, there are still other ways to make living easier and more comfortable for those that are affected with Krabbe, through various therapy options, equipment, and medications.
Thanks for reading our article on Krabbe's Disease! If you enjoyed reading this article, check out our article on Fast Food Addiction linked here. This article covers the dangers of the increasing prevalence of fast food in schools, and how we can combat it.
Until next time,
Harshita and the Writing Committee :)
Works Cited:
“Krabbe disease.” MedlinePlus, 1 January 2018, https://medlineplus.gov/genetics/condition/krabbe-disease/ Accessed 21 April 2023.
“Krabbe Disease | National Institute of Neurological Disorders and Stroke.” National Institute of Neurological Disorders and Stroke, 20 January 2023, https://www.ninds.nih.gov/health-information/disorders/krabbe-disease Accessed 21 April 2023