Complex sentence: The condition manifests itself as isolated hypogonadotropic hypogonadism (IHH) (reduced or absent puberty), and is responsible for approximately 50% of familial cases of IHH without anosmia.
Split into simpler sentences: The condition manifests itself as isolated hypogonadotropic hypogonadism (IHH) (reduced or absent puberty). It is responsible for approximately 50% of familial cases of IHH without anosmia.