Final answer:
The condition described is Fragile X Syndrome, a genetic disorder caused by CGG trinucleotide repeat expansion on the X chromosome, common in boys and characterized by developmental delays and physical features such as large ears, macrocephaly, and macro-orchidism.
Step-by-step explanation:
The question pertains to a genetic condition that is most commonly found in boys due to a mutation on the X chromosome, which features a number of physical characteristics such as macrocephaly, macro-orchidism, and large ears. The disorder in question that fits this description is Fragile X Syndrome (FXS), which is caused by the expansion of CGG trinucleotide repeats in the FMR1 gene located on the X chromosome. This disorder exhibits the phenomenon of anticipation, where the number of repeats tends to increase in each subsequent generation, potentially leading to more severe forms of the disorder.
Individuals with Fragile X Syndrome typically present with developmental delays, behavioral challenges, and in males, the physical traits as described. The disorder is also associated with connective tissue abnormalities and can present with features such as a long face with a prominent jaw, large ears, and enlarged testicles (macro-orchidism) in post-pubertal males.