GNE Myopathy is a progressive muscle disorder caused due to genetic mutations of the GNE gene. It is considered a Rare/NeglectedDisorder, which causes progressive skeletal muscular atrophy in young adults aged between 20-30 years. GNE Myopathy is also identified under other names such as Hereditary Inclusion Body Myopathy (HIBM), Quadriceps Sparing Myopathy (QSM), Distal Myopathy with Rimmed Vacuoles (DMRV), Nonuka Myopathy or IBM Type II Myopathy.
This Rare/Neglected genetic disorder causes distal muscles weakness, of legs and arms,at its onsetprogressing to proximal muscles in later stages. Initial symptoms include foot drop, difficulty in walking, infrequent steps, inability to climb stairs in its first stages, later followed by difficulty in standing up from squatting position, and weakness of hand and shoulder muscles. It does eventually lead to ambulation in later life.While progression and severity of the disorder varies from person to person, quadriceps muscles typically remain strong even in the later stages. The heart, respiratory muscles, speech and swallowing are usually not affected by GNE Myopathy.
The symptoms onset are typically seen in young adults aged between 20-30 years; however, there are cases where people over the age of 30 show their first sign of symptoms.
The disorder is a result of heterogeneous mutations in the GNE gene. The GNE protein (or enzyme) is needed for production of a small sugar called Sialic Acid which is found in all cells and tissues of our body. Sialic Acid is essential for the proper functioning of the body and is made by our cells with the help of a protein coded by GNE gene. While Sialic Acid can be supplemented from our food (milk, meat, etc.), it is mostly made up by our cells and therefore mutations in this gene can result in Sialic Acid deficiency which in turn, impairs overall function of the body and leads to gradual muscle weakness.
Mutations in this gene were first reported in Japanese and Persian Jewish populations. However, mutations have now been reported worldwide and don’t seem to be related to any particular region and ethnicity. The inheritance of GNE Myopathy is autosomal recessive. Both parents are usually unaffected carriers but can pass on a defect copy of the GNE gene to their affected child.
GNE Myopathy typically goes undiagnosed in its initial stages due to its close proximity of symptomatic similarities with other muscle disorders. It typically takes over 6-8 years before the actual diagnosis is confirmed leading to precious time being lost in early diagnosis and prognosis. Early diagnosis can prove crucial in hampering disease progression. Confirmed diagnosis can be sought by carrying out genetic testing and checking for mutations within the GNE gene. Mutations are spread across the entire length of the gene and therefore the entire GNE gene should be analysed for mutations. For information on how to get genetic testing done, please reach out to us at firstname.lastname@example.org.