It can be inherited but not all the time.

We all have a set of 2 genes, one from our mother, and one from our father. As a parent, we pass 1 of the 2 genes to a child. If the child receives 1 gene with a change (variant) from their mother and 1 gene with a change (variant) from their father, the child will have citrin deficiency. If a child receives 0 or 1 gene with a variant from either parent, the child will not have citrin deficiency.

This is because the gene with a variant will be masked in the presence of the gene without a variant. This type of gene is called a recessive gene.

For example, if one of the 2 genes from either parent has a variant, like the drawing below, there is a ¼ chance the child will have citrin deficiency and a 3⁄4 chance that they will not.

As seen here (What is Citrin Deficiency | Symptoms & Incidence), it is definitely not uncommon to be a carrier and the carrier rate will keep updating as new variants are found.