Rosenberg-Chutorian syndrome is an extremely rare genetic disorder characterized by the triad of hearing loss, degeneration of the optic nerve (optic atrophy) and neurological abnormalities, specifically disease of the nerves outside of the central nervous system (peripheral neuropathy). The arms and legs are most often affected by peripheral neuropathy. Rosenberg-Chutorian syndrome is inherited as an X-linked disorder with occasional mild symptoms present in the female carrier.
At least two other disorders are characterized by optic atrophy, hearing loss and peripheral neuropathy: Iwashita syndrome and Hagemoser syndrome. Most researchers consider these two disorders and Rosenberg-Chutorian syndrome separate disorders.
The symptoms of Rosenberg-Chutorian syndrome often become apparent during infancy or early childhood. The clinical triad of hearing loss, optic atrophy, and peripheral neuropathy characterizes the disorder.
Individuals with Rosenberg-Chutorian syndrome develop sensorineural hearing loss. In people with type of hearing impairment, sound may be conducted normally through the external and middle ear. However, sound vibrations are not properly transmitted to the brain due to a defect of the inner ear or the auditory nerve, resulting in hearing loss. (With normal hearing, a portion of the inner ear serves to convert sound vibrations to nerve impulses, which are then transmitted via the auditory nerve to the brain.) Although such sensorineural hearing loss is usually present at birth, it may not be detected until later during infancy. As affected children age, deafness may cause delays or impairment in speech development. Hearing loss may be slowly progressive.
Individuals with Rosenberg-Chutorian syndrome also develop degeneration (atrophy) of the optic nerve (optic atrophy). The optic nerve is the structure that sends electrical impulses from the retina to the brain. Optic atrophy results in the loss of visual acuity.
Noninflammatory disease affecting many nerves (polyneuropathy) is another sign of Rosenberg-Chutorian syndrome. The nerves outside the central nervous system, especially those of the arms and legs are affected (peripheral neuropathy). Individuals may develop weakness and wasting (atrophy) of the muscles in the arms and legs. Destruction of the fatty covering surrounding nerves (demyelination) has been present in a few affected individuals.
Rosenberg-Chutorian syndrome is caused by a mutation in the phosphoribosylpyrophosphate synthetase I (PRPS1) gene located on the X chromosome.
Rosenberg-Chutorian syndrome is inherited as an X-linked disorder. X-linked genetic disorders are conditions caused by an abnormal gene on the X chromosome and occur mostly in males. Females that have a disease gene present on one of their X chromosomes are carriers for that disorder. Carrier females usually do not display symptoms because females have two X chromosomes and one is inactivated so that the genes on that chromosome are nonfunctioning. It is usually the X chromosome with the abnormal gene that is inactivated. However, some females who carry a PRPS1 gene mutation show variably mild symptoms. Males have one X chromosome that is inherited from their mother and if a male inherits an X chromosome that contains a disease gene he will develop the disease. Female carriers of an X-linked disorder have a 25% chance with each pregnancy to have a carrier daughter like themselves, a 25% chance to have a non-carrier daughter, a 25% chance to have a son affected with the disease and a 25% chance to have an unaffected son.
Males with X-linked disorders pass the disease gene to all of their daughters who will be carriers. A male cannot pass an X-linked gene to his sons because males always pass their Y chromosome instead of their X chromosome to male offspring.
Rosenberg-Chutorian syndrome is a rare genetic disorder that affects males more often than females. Symptoms are more severe in males. Some carrier females may exhibit symptoms of the disorder.
Fewer than 10 cases have been reported in the medical literature. The disorder was first described in the medical literature in 1967.
A diagnosis of Rosenberg-Chutorian syndrome is made based upon a thorough clinical evaluation, a detailed patient history and identification of characteristic findings. Molecular genetic testing for PRSP1 gene mutations is available to confirm the diagnosis. Carrier testing and prenatal diagnosis are available if a PRSP1 gene mutation has been identified in an affected family member.
The treatment of Rosenberg-Chutorian syndrome is directed toward the specific symptoms that are apparent in each individual. Treatment may require the coordinated efforts of a team of specialists. Pediatricians, neurologists, speech pathologists, specialists who asses and treat hearing problems (audiologists), eye specialists, and other healthcare professionals may need to systematically and comprehensively plan an affected child's treatment.
Physical and occupational therapy may be useful to maintain as much functioning as possible. A cochlear implant may help individuals with hearing loss. Braces and other orthopedic devices may also be of aid in walking and moving.
Genetic counseling is recommended for affected individuals and their families. Other treatment is symptomatic and supportive.
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