Oculocutaneous albinism (OCA) is manifested by reduced synthesis of melanin, which may result from mutations in a variety of genes. In OCA, hypopigmentation is both cutaneous and ocular, and in the most common types of OCA, other tissues and organs are not significantly involved. Hypopigmentation of the skin is associated with psychological and social problems, decreases natural protection against sunburn, and results in predisposition to skin cancer. In the absence of melanin in the eye, development of the visual pathways is abnormal, resulting in decreased visual acuity, strabismus, nystagmus and photophobia.
One of the most common types of OCA is OCA1, an autosomal recessive disorder of reduced pigmentation in the hair, skin and eyes, resulting from mutations in the tyrosinase gene (TYR), a five exon gene spanning approximately 60 kb on chromosome 11q. Two different types of OCA1, A and B, can be distinguished in humans, based mainly on clinical observation, wherein OCA1A is the more severe type with absence of tyrosinase activity and pigmentation throughout life. The molecular basis of OCA1 is quite heterogeneous, and more than 190 mutations in the TYR gene have been identified so far in different population groups.
Al-Arrayed (Personal communication, Dubai, 2006) indicated that oculocutaneous albinism causes poor vision among some families in Bahrain frequently. However, further studies are needed to determine its prevalence.
Hegab (1984) studied 5 female cases of complete ocular albinism and the following clinical manifestations were noted: impaired vision, translucent irides, congenital nystagmus, photophobia, albinotic fundi, undeveloped fovea, complete color vision blindness and straight eyes with no strabismus. [Hegab S. Autosomal dominantly inherited albinism in females: report of five cases. Med J Cairo Univ. 1984; 52(1): 53-8.]
A survey performed by Bastaki et al. (1992) between 1985 and 1989 reported the overall incidence of genodermatosis in Kuwait Maternity Hospital to be 0.26 per 1000 livebirths. More specifically, the incidence of albinism was 0.024 per 1000 livebirths in Kuwait during the over-mentioned period of five years. [Bastaki L, Al-Awadi A, Naguib KK. Incidence of genodermatosis among the neonates in Kuwait Maternity Hospital: 1985 to 1989 survey report, Kuwait Medical Genetics Centre, 1992, Kuwait.]
Zahed et al. (2005) performed ophthalmic and dermatological examinations on 30 Lebanese subjects with OCA, then screened for mutations in the tyrosinase gene in an effort to establish the molecular basis of the disorder in Lebanon.
Rajab et al. (2005) undertook a study to estimate the prevalence of commonly diagnosed autosomal recessive diseases in Oman from a hospital-based register in years 1993 to 2002. The study revealed that oculocutaneous albinism was diagnosed in 14 patients, with an observed incidence of 1 in 30,000 births.