bone spicule pigmentation

Retinitis Pigmentosa 79

Clinical Characteristics
Ocular Features: 

As in many autosomal dominant conditions, there is considerable clinical heterogeneity and even nonpenetrance among individuals.  Onset may consist of night blindness in early childhood but many patients are not symptomatic until the 6th or 7th decade of life.  The fundus signs are characteristic for retinitis pigmentosa with bone spicule pigmentation clumps, attenuated vessels, optic disc pallor, and peripheral retinal atrophy.  Visual fields are peripherally constricted to variable degrees.   Patches of chorioretinal "degeneration" and choroidal "sclerosis" have been described.  Photophobia, decreased central acuity, and some degree of dyschromatopsia have been reported.  Progression of symptoms is highly variable but central acuity is usually affected at some point.

Systemic Features: 

No systemic abnormalities have been reported.

Genetics

This autosomal dominant type of retinitis pigmentosa seems to result from heterozygous mutations in the HK1 gene (10q22.1).  Its phenotype is nonpenetrant in some individuals.   

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

No treatment has been reported but low vision aids might be helpful especially for near vision.

References
Article Title: 

A dominant mutation in hexokinase 1 (HK1) causes retinitis pigmentosa

Sullivan LS, Koboldt DC, Bowne SJ, Lang S, Blanton SH, Cadena E, Avery CE, Lewis RA, Webb-Jones K, Wheaton DH, Birch DG, Coussa R, Ren H, Lopez I, Chakarova C, Koenekoop RK, Garcia CA, Fulton RS, Wilson RK, Weinstock GM, Daiger SP. A dominant mutation in hexokinase 1 (HK1) causes retinitis pigmentosa. Invest Ophthalmol Vis Sci. 2014 Sep 4;55(11):7147-58.

PubMed ID: 
25190649

Retinitis Pigmentosa 76

Clinical Characteristics
Ocular Features: 

Onset of night blindness occurs early in the second decade of life.  Vision is in the range of 20/40 to 20/100 in the first decades worsens slowly but there is a wide range.  Some older individuals may have hand motion vision in at least one eye but some retain 20/40.  All patients have peripheral field restrictions and some have pallor of the optic disc.  Retinal vessels are attenuated.  Fundus pigmentation is usually abnormal with some combination of bone spicule and diffuse salt and pepper pigmentation.  The macula is usually involved with a flat fovea, cystoid macular edema, and chorioretinal atrophy.

Retinal thinning is seen on OCT.  The ERG can be flat but in some individuals the rod responses are primarily reduced.

Systemic Features: 

No systemic abnormalities have been associated.

Genetics

Homozygous or compound heterozygous mutations in the POMGNT1 gene (1p34) are responsible for this disorder.

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No effective treeatment is available.

References
Article Title: 

Mutations in POMGNT1 cause non-syndromic retinitis pigmentosa

Xu M, Yamada T, Sun Z, Eblimit A, Lopez I, Wang F, Manya H, Xu S, Zhao L, Li Y, Kimchi A, Sharon D, Sui R, Endo T, Koenekoop RK, Chen R. Mutations in POMGNT1 cause non-syndromic retinitis pigmentosa. Hum Mol Genet. 2016 Apr 15;25(8):1479-88.

PubMed ID: 
26908613

Retinitis Pigmentosa 42

Clinical Characteristics
Ocular Features: 

The fundus phenotype of retinitis pigmentosa appears late.  Night vision difficulties are prominent symptoms but the age of onset is unknown. Reduction in visual acuity is variable and is usually not manifest until 50 years of age but it may remain near normal or in that range for another decade or two.  Concentric constriction (within 10-20 central degrees) in peripheral fields can be a presenting symptom and may not appear until age 65 years of age.  Patches of visual field retention can sometimes be demonstrated in the periphery.  Rod and cone full field ERG amplitudes are substantially reduced

Systemic Features: 

None.

Genetics

Heterozygous mutations in KLHL7 (7p15.3) segregate with the clinical phenotype.

Homozygous mutations in the KLHL7 gene cause cold-induced sweating syndrome 3 (CISS3) (617055).

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

None known.

References
Article Title: 

Mutations in a BTB-Kelch protein, KLHL7, cause autosomal-dominant retinitis pigmentosa

Friedman JS, Ray JW, Waseem N, Johnson K, Brooks MJ, Hugosson T, Breuer D, Branham KE, Krauth DS, Bowne SJ, Sullivan LS, Ponjavic V, Granse L, Khanna R, Trager EH, Gieser LM, Hughbanks-Wheaton D, Cojocaru RI, Ghiasvand NM, Chakarova CF, Abrahamson M, Goring HH, Webster AR, Birch DG, Abecasis GR, Fann Y, Bhattacharya SS, Daiger SP, Heckenlively JR, Andreasson S, Swaroop A. Mutations in a BTB-Kelch protein, KLHL7, cause autosomal-dominant retinitis pigmentosa. Am J Hum Genet. 2009 Jun;84(6):792-800.

PubMed ID: 
19520207
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