This information is provided by the National Institutes of Health (NIH) Genetic and Rare Diseases Information Center (GARD).
Senior Loken syndrome (SLS) is a rare syndrome that mainly affects the kidneys and eyes. SLS causes a cystic kidney disease called nephronophthisis, which usually begins in early childhood. The kidneys develop cysts, inflammation, and scarring, which progressively impair kidney function. Symptoms of nephronophthisis may include increased production of urine, excessive thirst, weakness, and severe fatigue. Nephronophthisis typically leads to end-stage kidney disease by adolescence.
SLS affects the eyes by causing varying degrees of retinal dystrophy, which is progressive wasting of the retina (the part of the eye that senses light and sends images to the brain). Some children with SLS have a severe type of retinal dystrophy at birth called Leber congenital amaurosis (LCA). Symptoms of LCA include severe farsightedness, light sensitivity (photophobia), and nystagmus. Other children with SLS do not have LCA but later develop symptoms of a retinal dystrophy called retinitis pigmentosa (RP). Symptoms of RP range in age of onset and severity, and may include night blindness, progressive loss of peripheral vision, and eventual loss of central vision, leading to blindness.
In rare cases, additional symptoms such as liver fibrosis or skeletal abnormalities have been reported.
SLS may be caused by mutations in any of several genes, and inheritance is autosomal recessive. The syndrome can be diagnosed based on symptoms, kidney and eye evaluations, and genetic testing.
Treatment during earlier stages of kidney disease in children includes maintaining a healthy balance of fluid and electrolytes. End-stage kidney disease requires dialysis, or kidney transplantation. After transplantation, kidney damage does not occur again. End-stage kidney disease can be life-threatening if not treated. There is currently no treatment to prevent or stop the progression of vision loss due to retinal dystrophy, but various low-vision aids may be helpful for those who have remaining vision.
For more information, visit GARD.