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Healey et al., 2014
Are worldwide Albinism prevalence figures an accurate reflection? An
incidental finding from a Northern Ireland study
Person 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. Grønskov 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) Study
A 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.
Discussion
Due 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
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Healey et al., 2014
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.
Conclusion
The 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.
References:
1. Pearson K, Nettleship E, Usher CH. A Monograph of Albinism in Man 19111913; London Cambridge Univerity Press (cited in Kinnear PE, Barrie J,
Witkop CJ. Albinism. Surv Ophthalmol 1985;30:75–101)**Double Check
Reference quite either Pearson or Kinnear?
2. Witkop CJ, White JG, Nance W et al. Classification of albinism in man. Birth
Defects Orig Art Ser 1971;7:13–25
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Healey et al., 2014
3. Grønskov K, Ek J, Sand A, Scheller R, et al. Birth Prevalence and mutation
spectrum in Danish patients with autosomal recessive albinism. Investigative
Ophthalmology and Vision Science March 2008;50:1058-1064
4. Froggatt P. Albinism in Northern Ireland. Annals. of Human Genetics 1960;
24:213-238.
5. Sarvananthan N, Surendran M, Roberts EO, et al. Prevalence of Nystagmus:
The Leicestershire Nystagmus Survey. Investigative Ophthalmology and
Visual Science. November 2009;11:5201-6.
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