SNP Shot: Genomic Insights

ALG12-congenital disorder of glycosylation (ALG12-CDG), also called congenital disorder of glycosylation type Ig, is a genetic condition affecting multiple body systems, with a wide range of symptoms. The signs and symptoms of ALG12-CDG usually appear in infancy and can include feeding difficulties, failure to thrive (poor growth and weight gain), intellectual disability, developmental delays, and low muscle tone (hypotonia). Some individuals may also experience seizures.

Some individuals with ALG12-CDG exhibit physical differences, such as a smaller than normal head size (microcephaly) and distinct facial characteristics. These facial features may include epicanthal folds (skin folds at the inner corner of the eyes), a prominent nasal bridge, and unusually shaped ears. Males with ALG12-CDG may have genital abnormalities like a small penis (micropenis) and undescended testicles.

A common finding in ALG12-CDG is abnormally low levels of antibodies (immunoglobulins), especially immunoglobulin G (IgG). Antibodies are crucial for fighting infections by identifying and targeting foreign substances and germs for elimination. Reduced antibody levels can compromise the body's ability to combat infections.

Less frequently, individuals with ALG12-CDG may experience a weakened heart muscle (cardiomyopathy) and impaired bone development, potentially leading to skeletal problems.

Inheritance:

ALG12-CDG follows an autosomal recessive inheritance pattern. This means that to develop the condition, an individual must inherit a mutated copy of the responsible gene from each parent. The parents, who each carry only one copy of the mutated gene, are typically unaffected and do not exhibit symptoms of the condition.