The rate appeared lower in Australia, where data from states with full population-based ascertainment listed DCP as the predominant motor type in only 7% of the cases. The differences reported from various registers and countries may relate to under-identification of dyskinetic CP due to a lack of standardization in definition and classification based on predominant type. == References ==
Diagnosis
Screening for retinoblastoma should be part of a "well baby" screening for newborns during the first 3 months of life, to include:
The red reflex: checking for a normal reddish-orange reflection from the eyes retina with an ophthalmoscope or retinoscope from about 30 cm or 1 foot, usually done in a dimly lit or dark room
The corneal light reflex or Hirschberg test: checking for symmetrical reflection of beam of light in the same spot on each eye when a light is shined into each cornea, to help determine whether the eyes are crossed
Eye examination: checking for any structural abnormalities

Classification
The two forms of the disease are a heritable form and nonheritable form (all cancers are considered genetic in that mutations of the genome are required for their development, but this does not imply that they are heritable, or transmitted to offspring). Around 55% of children with retinoblastoma have the nonheritable form. If no history of the disease exists within the family, the disease is labeled "sporadic", but this does not necessarily indicate that it is the nonheritable form. Bilateral retinoblastomas are commonly heritable, while unilateral retinoblastomas are commonly nonheritable.In about two-thirds of cases, only one eye is affected (unilateral retinoblastoma); in the other third, tumors develop in both eyes (bilateral retinoblastoma). The number and size of tumors on each eye may vary. In certain cases, the pineal gland or the suprasellar or parasellar region (or in very rare cases other midline intracranial locations) is also affected (trilateral retinoblastoma).