Are worldwide albinism prevalence figures an accurate reflection? An incidental finding from a Northern Ireland study

Are worldwide Albinism prevalence figures an accurate reflection? An incidental finding from a Northern Ireland studyPerson et al.,1 and Witkop et al.,2 suggest global prevalence figures for albinism of 1 in 18,000, and 1 in 17,000 respectively. Person et al.’s 1 figure is widely quoted in the literature but it is unclear how it was derived. Gronskov et al.,3 investigated birth prevalence and mutation spectrum in Danish patients with autosomal recessive albinism suggesting a minimum birth prevalence of 1 in 14,000. Similarly Froggatt4 had investigated the occurrence of albinism in Northern Ireland (NI) in 1960 and reported a prevalence of 1 in 10,000. Clearly there are discrepancies in the literature in terms of the prevalence of albinism.The Northern Ireland Nystagmus and Albinism (NINA) StudyA three year study investigating the visual and refractive profile of a population of children and adults with albinism (and control group with nystagmus) took place in NI. The Northern Ireland Nystagmus and Albinism (NINA) Study employed mass triangulation techniques to ensure maximum recruitment through the two main tertiary ophthalmic centres in NI as well as from local eye charities, and qualified teachers of the visually impaired (QTVI). The number of individuals within the study age group (0-39 years) with albinism, was estimated to be 97 based on published prevalence figures specific to NI (1 in 10,000 4). However, 148 individuals with albinism were identified (aged 0-39 years). When observing incidence of albinism in NI, once again a higher than expected occurrence was demonstrated. During a 36 month period (January 2008-December 2010) seventeen children born with albinism were recruited (7 infants born in 2010, 4 in 2009 and 6 in 2008), compared with an expected incidence of 2-3 per year.DiscussionDue to the difficulty of identifying undiagnosed cases of albinism (with minimal visual dysfunction) outside the hospital eye service (HES), from a mainly Caucasian population, it is unlikely that all those in NI living with albinism or born with this condition during the study period, were identified. Nonetheless, based on the number of individuals that were identified, the authors propose that the estimated incidence rate of albinism in NI is at least 1 in 4,500, and that estimated prevalence is at least 1 in 6,600. This is greater than the prevalence suggested by Froggatt in the 1960s. These findings support the work of Sarvanathan et al.,5 who reported a prevalence of 1 in 4,000 people with albinism in Leicestershire (UK). It is the authors’ opinion that albinism is not on the increase, rather that more individuals are being correctly diagnosed with albinism due to advancement in healthcare and diagnostic techniques, as well as increased awareness.ConclusionThe increase in numbers of people with albinism living in NI has socio-economic implications for service provision, with an increased number of families entitled to Disability Living Allowance (DLA) and other benefits (Registration as Severely Sight Impaired/Sight Impaired). Additionally, a greater number of children needing spectacles, visual aids, HES appointments, educational assessments and classroom assistants must be taken into consideration when planning future services. Although the present study was not an epidemiological prevalence survey it has highlighted that there is a larger than expected occurrence of albinism in NI. The authors suspect that this is not an isolated case and in fact that worldwide figures such as 1 in 18,000 are a significant underestimation of true prevalence.