Alström syndrome

Alström syndrome is a rare autosomal recessive disorder caused by pathogenic variants in ALMS1. It commonly causes progressive vision and hearing loss, childhood-onset obesity, and metabolic, renal, and cardiac complications.

Primary cilium: The primary cilium is a usually solitary, microtubule-based cell projection that senses signals and coordinates cellular responses. Alström syndrome belongs to disorders associated with primary-cilium dysfunction.
Cone-rod dystrophy: Cone-rod dystrophy is an inherited retinal degeneration affecting cone photoreceptors before or alongside rod photoreceptors. It commonly underlies early visual impairment in Alström syndrome.
Autosomal recessive inheritance: Autosomal recessive inheritance occurs when disease results from pathogenic variants in both copies of an autosomal gene. Alström syndrome usually occurs when a child inherits one altered ALMS1 copy from each parent.
Bardet–Biedl syndrome: Bardet–Biedl syndrome is a genetic ciliopathy often marked by retinal degeneration, obesity, polydactyly, and kidney abnormalities. It overlaps in obesity and retinal disease but often includes polydactyly, unlike Alström syndrome.
Ciliopathy: A ciliopathy is a genetic disorder caused by dysfunction of cilia or their associated proteins. This disease’s multisystem pattern arises from disrupted ciliary biology.
Nystagmus: Nystagmus is involuntary, rhythmic movement of the eyes. It can appear in infancy alongside the syndrome’s early retinal disease.
ALMS1: ALMS1 is a gene encoding a centrosomal and basal-body protein involved in ciliary function. Identifying ALMS1 variants established the molecular cause of the syndrome.
Usher syndrome: Usher syndrome is an inherited disorder combining sensorineural hearing loss with retinitis pigmentosa. It combines hearing and vision loss but lacks Alström syndrome’s characteristic obesity and metabolic disease.
Photoreceptor cell: A photoreceptor is a retinal cell that converts light into electrical signals. Progressive photoreceptor degeneration drives the syndrome’s vision loss.
Sensorineural hearing loss: Sensorineural hearing loss results from damage to the inner ear or auditory nerve pathways. Progressive inner-ear hearing loss is a characteristic feature.

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