What condition is characterized by a delayed puberty with a bone age less than chronological age?

The condition characterized by delayed puberty with a bone age that is less than chronological age is indeed constitutional pubertal delay. This condition often affects boys who experience a slower onset of secondary sexual characteristics and have a bone age that is notably younger than their actual age.

Typically, children with constitutional pubertal delay will eventually enter puberty and achieve normal adult height. This delay is often a variation of normal growth and development, usually linked to genetic factors or family history of late maturation.

In contrast, precocious puberty refers to the onset of secondary sexual characteristics at an unusually early age, which does not fit the criteria of delayed puberty. Klinefelter's syndrome and Turner syndrome are specific genetic conditions associated with hormonal abnormalities and secondary sexual characteristics but often have distinct clinical features that differ from a simple delayed onset of puberty. Klinefelter’s syndrome usually presents with tall stature and often primary hypogonadism, while Turner syndrome is characterized by short stature and other physical abnormalities, but both are not specifically focused on the delayed puberty aspect with bone age considerations seen in constitutional pubertal delay.