Metabolic Causes of Epilepsy

Most of these disorders are inherited genetically. The inheritance pattern is usually autosomal recessive or X-linked recessive.

Autosomal Recessive Disorder

• To have an autosomal recessive disorder, the person must have two copies of the abnormal gene. Usually, they inherit one of these copies from each parent. Each parent is a carrier, meaning that they have one abnormal gene (recessive gene) and one normal gene (dominant gene) for the condition, but their health is normal, as they have a normal gene.

X-Linked Recessive Inheritance

• X-linked recessive  inheritance means that the gene causing the trait or the disorder is located on the X chromosome, and that the disorder is only present if a second, normal copy X chromosome is not present. Females have two X chromosomes. Males have one X and one Y chromosome.  Because females typically have one abnormal gene and one normal gene, they are carriers and are not affected.
• When a carrier female has children with an unaffected male, their sons will have a 50% chance of inheriting the abnormal gene. All sons who inherit that gene will be affected. However, daughters will not be affected, but will have a 50% chance of being a carrier, as they have a 50% chance of inheriting the abnormal gene from their mother, but will inherit a normal X chromosome from their father.