Senior-Loken Syndromes
Patient Information
Characteristics
Background and History
Senior-Loken syndromes is discussed here as a group of disorders that have the common features of retinal and kidney disease. Of course, both retinal disease and kidney disease also occur separately and may be inherited as well. Aagot Christie Loken was a Norwegian neuropathologist and Boris Senior an African pediatrician.
Clinical Correlations
The retinal pigmentation seen in Senior-Loken syndrome is highly variable in appearance and age of onset. Infants less than a year old may have severe visual difficulties with minimal changes visible in their retinas, but some patients may not experience visual difficulties until the second and third decades. Many patients have severe constriction (loss of side vision) of their visual fields.
The kidney disease likewise is variable in the age of onset and rate of progression. It may present as an anemia but in most cases excessive urination and thirst are the first symptoms. Kidney failure eventually occurs as most of the kidney is replaced by cysts.
Genetics
Inheritance
All of the disorders in this group are inherited in autosomal recessive patterns, in which each of the normal carrier parents with a single mutation contribute it to one-fourth of their children.
Pedigree
Autosomal recessive
In order for autosomal recessive disorders to be expressed, offspring generally must inherit two mutations, one from each carrier parent. Carriers with only one mutation, such as the parents, do not have clinical disease. Note that carrier parents can expect that 1 in 4 children (25%) will inherit both mutations and have the disorder, 2 in 4 children (50%) will be carriers like their parents, while 1 in 4 children (25%) inherit neither mutation.
In order for autosomal recessive disorders to be expressed, offspring generally must inherit two mutations, one from each carrier parent. Carriers with only one mutation, such as the parents, do not have clinical disease. Note that carrier parents can expect that 1 in 4 children (25%) will inherit both mutations and have the disorder, 2 in 4 children (50%) will be carriers like their parents, while 1 in 4 children (25%) inherit neither mutation.
Diagnosis and Prognosis
Pediatricians, ophthalmologists and kidney specialists usually collaborate on this diagnosis. The kidney disease is the most life-threatening and often requires a renal transplant. The vision loss may require low vision aids which can enable better vision functioning.
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