Leber congenital amaurosis (LCA) is a form of congenital blindness in humans and is known to be caused by homozygosity for recessive mutations in the RPE65 gene. Recently, a rare dominant mutation in RPE65 has been implicated as one cause of an eye disease called retinitis pigmentosa, which is characterized by retinal degeneration that can progress to blindness. The dominant RPE65 mutation is a missense mutation causing amino acid 447 in the polypeptide to change from Asp to Glu. Little is known about the nature of the mutant protein. a. Do you think that the dominant allele is more likely a loss-of-function or a gain-of-function mutation? Explain. b. Recently a group of clinicians and scientists reported that gene therapy (gene replacement therapy) for LCA has been at least partially successful. Do you think that the same kind of gene therapy can be used for patients with retinitis pigmentosa caused by the dominant mutant allele of RPE65? Explain.
Leber congenital amaurosis (LCA) is a form
of congenital blindness in humans and is
known to be caused by homozygosity for
recessive mutations in the RPE65 gene.
Recently, a rare dominant mutation in RPE65
has been implicated as one cause of an eye
disease called retinitis pigmentosa, which is
characterized by retinal degeneration that
can progress to blindness. The dominant
RPE65 mutation is a missense mutation
causing amino acid 447 in the polypeptide to
change from Asp to Glu. Little is known about
the nature of the mutant protein.
a. Do you think that the dominant allele is more
likely a loss-of-function or a gain-of-function
mutation? Explain.
b. Recently a group of clinicians and scientists
reported that gene therapy (gene
replacement therapy) for LCA has been at
least partially successful. Do you think that
the same kind of gene therapy can be used
for patients with retinitis pigmentosa caused
by the dominant mutant allele of RPE65?
Explain.
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