OMIM ID:
Albinism, Oculocutaneous, Type V
Alternate Names
Defective Genes
Clinical Characteristics
Ocular Features
The phenotype in the two families studied includes photophobia, nystagmus, foveal hypoplasia and decreased visual acuity. The fundus is hypopigmented.
Systemic Features
The hair is golden-colored and the skin is described as white.
Genetics
Inheritance
The specific gene causing this form of oculocutaneous albinism has not been identified. However, an area of homozygosity in the region of 4q24 has been identified in 6 members in two families belonging to a large consanguineous Pakistani pedigree in which it segregates with the OCA5 phenotype.
Pedigree
Autosomal recessive
In order for autosomal recessive disorders to be expressed, offspring generally must inherit two mutations, one from each carrier parent. Carriers with only one mutation, such as the parents, do not have clinical disease. Note that carrier parents can expect that 1 in 4 children (25%) will inherit both mutations and have the disorder, 2 in 4 children (50%) will be carriers like their parents, while 1 in 4 children (25%) inherit neither mutation.
In order for autosomal recessive disorders to be expressed, offspring generally must inherit two mutations, one from each carrier parent. Carriers with only one mutation, such as the parents, do not have clinical disease. Note that carrier parents can expect that 1 in 4 children (25%) will inherit both mutations and have the disorder, 2 in 4 children (50%) will be carriers like their parents, while 1 in 4 children (25%) inherit neither mutation.