Retinitis Pigmentosa 47

Clinical Characteristics

Ocular Features:

Onset of night blindness and field constriction symptoms occur during the 4th and 5th decades of life. Pigmentary abnormalities of the retina are the hallmark of this condition. Retinal thinning, bone spicule pigmentation, vascular attenuation, optic disc pallor, and pigmentary atrophy have all been noted.

In patients with the autosomal dominant form of this disease, rod function is severely impaired or absent as evidenced by ERG studies. Cone responses are often reduced on an age-related basis and in the range of 85-95% below normal. As expected, dark-adapted visual thresholds are elevated and visual fields are restricted peripherally. Loss of vision is age-related but some individuals can retain acuities of 20/35 to 20/40 into their sixth decade. It is more common for acuities to be in the range of 20/200 to 20/400 later in life.

Systemic Features:

No systemic disease is associated with this disorder.

Genetics

Mutations in the SAG [1] gene (2q37) are responsible for this form of RP. Both autosomal recessive and autosomal dominant modes of inheritance have been reported.

In one family with homozygous mutations a sib had features of Oguchi disease [2] which also results from homozygous mutations in SAG [1].

Among Hispanic families in the southwestern US, heterozygous mutations in SAG [1] are a common cause of autosomal dominant retinitis pigmentosa.

Treatment

Treatment Options:

No treatment has been reported for this disorder.

References

Article Title:

A Novel Dominant Mutation in SAG, the Arrestin-1 Gene, Is a Common Cause of Retinitis Pigmentosa in Hispanic Families in the Southwestern United States [3]

Sullivan LS, Bowne SJ, Koboldt DC, Cadena EL, Heckenlively JR, Branham KE, Wheaton DH, Jones KD, Ruiz RS, Pennesi ME, Yang P, Davis-Boozer D, Northrup H, Gurevich VV, Chen R, Xu M, Li Y, Birch DG, Daiger SP. A Novel Dominant Mutation in SAG, the Arrestin-1 Gene, Is a Common Cause of Retinitis Pigmentosa in Hispanic Families in the Southwestern United States. Invest Ophthalmol Vis Sci. 2017 May 1;58(5):2774-2784.

PubMed ID:

28549094

Arrestin gene mutations in autosomal recessive retinitis pigmentosa [4]

Nakazawa M, Wada Y, Tamai M. Arrestin gene mutations in autosomal recessive retinitis pigmentosa. Arch Ophthalmol. 1998 Apr;116(4):498-501.

PubMed ID:

9565049