Lithuanian University of Health Sciences (LSMU) Entrance Practice exam

X-linked recessive disorders are characterized by their distinct inheritance pattern, which predominantly affects males more frequently than females. This is due to the presence of one X chromosome in males (XY), compared to females who have two X chromosomes (XX). If a male inherits a recessive allele on his single X chromosome, he will express the disorder because there is no corresponding allele on the Y chromosome to mask the effect. Females, having two X chromosomes, typically require two copies of the recessive allele to manifest the disorder, which is why they are less frequently affected and can often be carriers without showing symptoms.

This particular pattern means that while females can be carriers of the disorder (having one affected X chromosome and one normal X chromosome), males cannot, as they do not have a second X chromosome that could potentially counteract the effect of a recessive allele. Therefore, while females may transmit the allele to their offspring, it's the males who are more visibly affected when they inherit the gene mutation associated with the disorder.