Early-onset Alzheimer's disease may be associated with sortilin-related receptor 1 gene mutation: A family report and review

Background: Early-onset Alzheimer's disease is a rare condition that differs from the usual memory-disordered presentation of typical Alzheimer's disease. Early-onset Alzheimer's disease is believed to have a genetic basis, and sporadic Alzheimer's disease has been associated with sortilin-related receptor 1 polymorphism. Case presentation: This report describes and discusses the family report of a 59-year-old patient with early-onset Alzheimer's disease that may have been associated with a sortilin-related receptor 1 gene mutation. The patient was hospitalized in August 2008 for gradually progressive amnesia. Brain magnetic resonance imaging showed that the patient presented with whole-brain atrophy (especially in the bilateral medial temporal lobe and hippocampus). He had an initial Mini-Mental State Examination score of 15 (time orientation: 4/5; place orientation: 4/5; language immediate memory: 2/3; attention and calculation: 1/5; delayed memory: 0/3; naming: 1/2; language retelling, understanding, and expression: 3/6; visuospatial ability: 0/1). Whole-exome sequencing showed a sortilin-related receptor 1 gene mutation, c.3575G>A (chr11:121448104), which was detected in the patient and his children. Discussion: Patients with early-onset Alzheimer's disease present with obvious deficits in language, visuospatial abilities, praxis, or other nonmemory cognitive functions. In this case, the speech, memory, and visuospatial impairment of the patient may be associated with the sortilin-related receptor 1 gene mutation. Atrophy of the bilateral medial temporal lobe/hippocampus on magnetic resonance imaging may be an important marker of early-onset Alzheimer's disease. A sortilin-related receptor 1 gene mutation, c.3575G>A (chr11:121448104), may increase the risk of Alzheimer's disease.