Also known as Congenital Disorder of Glycosylation Type It
A rare, multisystemic, inherited condition caused by an abnormal protein disrupting glycosylation. Symptoms manifest in infancy, including hypoglycemic seizures, hypotonia (low muscle tone), liver disease, motor developmental delay, failure to thrive, a cleft palate, cardiomyopathy, myopathy, muscle atrophy, rhabdomyolysis, exercise intolerance, and blood clots.
PGM1-CDG is an inherited condition that affects many parts of the body. Individuals with PGM1-CDG typically develop signs and symptoms of the condition during infancy. Affected infants may have seizures due to low blood sugar levels, weak muscle tone, motor developmental delay, and a failure to gain weight and grow at the expected rate (failure to thrive). Infants with PGM1-CDG are frequently born with cleft palate. Laboratory abnormalities include elevated liver enzymes, abnormal coagulation factor activities and hormonal imbalance (low blood sugar, hypothyroidism, growth hormone deficiency). Intellectual disability is rare in PGM1-CDG. Affected individuals may also develop a heart condition called cardiomyopathy (insufficient pump function of the heart). Individuals with PGM1-CDG who have cardiomyopathy might die in childhood.
During adolescence or adulthood, individuals with PGM1-CDG frequently have weakness in their arms and legs (myopathy), episodes of painful muscle symptoms and muscle wasting (rhabdomyolysis), exercise intolerance, and some individuals might develop thrombosis (blood clots in the deep veins). There are more the 50 PGM1-CDG patients published in the medical literature
Diagnostic testing relies on testing the appropriate glycosylation of common proteins (one commonly used glycoprotein is transferrin). This can be tested by different methods in blood. Measuring the activity of the enzyme protein, PGM1 is also possible in blood and skin fibroblasts. The ultimate diagnosis is genetic testing in blood. Individuals with PGM1-CDG have two faulty copies of the PGM1 gene.
Treatment and Prognosis
There is an effective nutritional intervention treatment for PGM1-CDG, by oral D-galactose supplementation (D-galactose 1g/kg/day, maximum dose 50g/day). Due to the fact that not all symptoms fully recover on this therapy, the rest of the treatment focuses on the treatment of symptoms and prevention of complications, including complex carbohydrate rich diet, supportive heart treatment, physical therapy etc.).
PGM1-CDG have a good life expectancy. The oldest PGM1-CDG patient is in her late 40s.