A female with x-linked ornithine transcarbamylase enzyme deficiency (case report)‎

الملخص EN

Inborn errors of metabolism (IEM) are collectively quite common disorders and they usually have an autosomal recessive inheritance pattern.

X-linked recessive diseases are less common and they affect the male gender mostly.

If a male has a mutant gene on the X chromosome, it will express a phenotype, as there is no normal allele.

On the other hand, females with a healthy allele will not express the disease.

In rare cases and due to the Lyonization phenomenon of the X chromosome in females, a mutant allele can express a disease if it lyonized over the healthy one.

In these rare cases of females affected with an X-linked recessive disease, the disease usually presents mild or intermittent.

Therefore the diagnosis would be challenging.

Our case is about a 2-year-old female with ornithine transcarbamylase (OTC) enzyme deficiency.

OTC is one of the urea cycle enzymes coded on the X chromosome and usually presents with hyperammonaemic encephalopathy.