Prevalence and Incidence of Oculocerebral hypopigmentation syndrome, type Preus
Ophanet, who are a consortium of European partners,
currently defines a condition rare when if affects 1 person per 2,000.
They list Oculocerebral hypopigmentation syndrome, type Preus as a "rare disease".
More information about Oculocerebral hypopigmentation syndrome, type Preus is available from Orphanet
About prevalence and incidence statistics:
The term 'prevalence' of Oculocerebral hypopigmentation syndrome, type Preus usually refers to the estimated population
of people who are managing Oculocerebral hypopigmentation syndrome, type Preus at any given time.
The term 'incidence' of Oculocerebral hypopigmentation syndrome, type Preus refers to the annual diagnosis rate,
or the number of new cases of Oculocerebral hypopigmentation syndrome, type Preus diagnosed each year.
Hence, these two statistics types can differ:
a short-lived disease like flu can have high annual incidence but low prevalence,
but a life-long disease like diabetes has a low annual incidence but high prevalence.
For more information see about prevalence and incidence statistics.