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Forestry Tags > Tag based links for Albinism
The following links have been tagged albinism by users just like you, because these resources are off-site we cannot guarantee the accuracy or quality of any third-party information.
- An intragenic
deletion of
the P gene is
the common
mutation
causing
tyrosinase-pos
itive
oculocutaneous
albinism in
southern
African
Negroids.: Am J Hum
Genet, Vol.
56, No. 3.
(March 1995),
pp.
586-591.Tyrosi
nase-positive
oculocutaneous
albinism
(OCA2), an
autosomal
recessive
disorder of
the melanin
biosynthetic
pathway, is
the most
common
recessive
disorder
occurring in
southern
African
Bantu-speaking
Negroids, with
an overall
prevalence of
1/3,900. The
OCA2 gene, P,
has been
mapped to
chromosome
15q11-q13, and
recently
alterations in
the P gene
have been
identified in
OCA2
individuals.
An intragenic
deletion has
been described
and proposed
to be of
African origin
because of its
occurrence in
four unrelated
African
American OCA2
individuals
and in two
individuals,
one from Zaire
and the other
from Cameroon.
This study
shows that the
intragenic
deletion is a
common cause
of OCA2 in
southern
African
Negroids
(114/146
[.78]; OCA2
chromosomes)
and is
associated
with one
common
haplotype
(43/55 [.78];
OCA2
chromosomes),
confirming the
African origin
of this
allele. On the
basis of
haplotype
data, it would
appear that at
least seven
additional,
less frequent
OCA2 mutations
occur in this
population.
Source: Am J Hum Genet, Vol. 56, No. 3. (March 1995), pp. 586-591. - Oculocutaneous
albinism
(OCA2) in
sub-Saharan
Africa:
distribution
of the common
2.7-kb P gene
deletion
mutation.: Hum Genet,
Vol. 99, No.
4. (April
1997), pp.
523-527.Oculoc
utaneous
albinism
(OCA2) is the
most common
autosomal
recessive
disorder in
the South
African
Negroid
population,
occurring with
a prevalence
of 1/3900
individuals.
The OCA2
locus, P, has
been mapped to
chromosome
15q11-q13 and
a 2.7-kb
interstitial
deletion has
been found to
be the common
mutation in
Africa. This
study reports
the detection
of the
deletion
allele in
OCA2-affected
individuals
from the
southern
African,
Zambian and
Central
African
Republic (CAR)
Negroid
populations
(0.77, 131/170
OCA2
chromosomes;
0.79, 11/14;
0.33, 4/12,
respectively).
Normally
pigmented
individuals
from different
African
countries were
also tested.
The deletion
mutation was
found at a
frequency of
0.013 (10/780)
in the
normally
pigmented
southern
African
Negroid
population and
at a lower
frequency in
individuals
from central
Africa (0.002;
2/834),
including
individuals
from Zambia,
Cameroon,
Zaire and the
CAR. The study
confirms the
African origin
of this
deletion
allele.
Haplotype
analysis
suggests that
the deletion
mutation
probably
occurred only
once and that
it arose
before the
divergence of
these African
populations,
which is
estimated to
be about
2000-3000
years ago. The
unusually high
frequency of
OCA2
mutations, in
particular the
2.7-kb
deletion,
suggests some
selective
agent or
genetic drift.
Source: Hum Genet, Vol. 99, No. 4. (April 1997), pp. 523-527.
If you would like to find additional social bookmark based links on the topic of albinism we recommend the Open Tag Directory > Albinism. If you would like to find related tags we recommend Tag Patterns > Albinism.
