BACKGROUND: Variability of age at onset (AO) of Alzheimer disease (AD) among members of the same family is important as a biological clue and because of its clinical effects. OBJECTIVE: To evaluate which clinical variables influence the discrepancy in AO among affected relatives with familial AD. SETTING: Clinical genetic project of Spanish kindred with AD conducted by 4 academic hospitals in Madrid, Spain. METHODS: Age at onset of AD in 162 families and discrepancy in AO in intragenerational and intergenerational affected pairs were analyzed in relation to age, sex, maternal or paternal transmission, pattern of inheritance, and apolipoprotein E genotype. RESULTS: Maternal transmission of AD was significantly more frequent than paternal transmission (P < .001). In 27% of the affected individuals, AO occurred before the patient was 65 years old. Discrepancy in AO among siblings was within 5 years in 44% of the families, 6 to 10 years in 29%, and more than 10 years in 27% (range, 0-22). This discrepancy was independent of the sex of the sibling pairs and was significantly lower with maternal transmission of AD (P = .02). Segregation analysis showed no differences in the inheritance pattern between families with low (< or =5 years) or high (>5 years) AO discrepancy. Age at onset in carriers of the apolipoprotein E epsilon4 allele was slightly younger. However, among siblings, an extra apolipoprotein E epsilon4 allele was not consistently associated with earlier onset of AD. Eighty percent of patients, independent of sex or mode of transmission, were already affected at their parents' reported AO. CONCLUSIONS: There is a wide discrepancy in AO in affected siblings that is not clearly explained by a single clinical variable or apolipoprotein E genotype. The interaction of many factors probably determines AO in each affected individual. However, maternal transmission of AD seems to result in a similar AO in offspring, and the risk of developing dementia after the parent's reported AO decreases significantly.
BACKGROUND: Variability of age at onset (AO) of Alzheimer disease (AD) among members of the same family is important as a biological clue and because of its clinical effects. OBJECTIVE: To evaluate which clinical variables influence the discrepancy in AO among affected relatives with familial AD. SETTING: Clinical genetic project of Spanish kindred with AD conducted by 4 academic hospitals in Madrid, Spain. METHODS: Age at onset of AD in 162 families and discrepancy in AO in intragenerational and intergenerational affected pairs were analyzed in relation to age, sex, maternal or paternal transmission, pattern of inheritance, and apolipoprotein E genotype. RESULTS: Maternal transmission of AD was significantly more frequent than paternal transmission (P < .001). In 27% of the affected individuals, AO occurred before the patient was 65 years old. Discrepancy in AO among siblings was within 5 years in 44% of the families, 6 to 10 years in 29%, and more than 10 years in 27% (range, 0-22). This discrepancy was independent of the sex of the sibling pairs and was significantly lower with maternal transmission of AD (P = .02). Segregation analysis showed no differences in the inheritance pattern between families with low (< or =5 years) or high (>5 years) AO discrepancy. Age at onset in carriers of the apolipoprotein E epsilon4 allele was slightly younger. However, among siblings, an extra apolipoprotein E epsilon4 allele was not consistently associated with earlier onset of AD. Eighty percent of patients, independent of sex or mode of transmission, were already affected at their parents' reported AO. CONCLUSIONS: There is a wide discrepancy in AO in affected siblings that is not clearly explained by a single clinical variable or apolipoprotein E genotype. The interaction of many factors probably determines AO in each affected individual. However, maternal transmission of AD seems to result in a similar AO in offspring, and the risk of developing dementia after the parent's reported AO decreases significantly.
Authors: Lisa Mosconi; Wai Tsui; John Murray; Pauline McHugh; Yi Li; Schantel Williams; Elizabeth Pirraglia; Lidia Glodzik; Susan De Santi; Shankar Vallabhajosula; Mony J de Leon Journal: Neurobiol Aging Date: 2011-04-22 Impact factor: 4.673
Authors: Katherine Reiter; Kathryn I Alpert; Derin J Cobia; Mary J Kwasny; John C Morris; John C Csernansky; Lei Wang Journal: Neuroimage Date: 2012-04-05 Impact factor: 6.556
Authors: Lisa Mosconi; Juha O Rinne; Wai H Tsui; John Murray; Yi Li; Lidia Glodzik; Pauline McHugh; Schantel Williams; Megan Cummings; Elizabeth Pirraglia; Stanley J Goldsmith; Shankar Vallabhajosula; Noora Scheinin; Tapio Viljanen; Kjell Någren; Mony J de Leon Journal: Neurobiol Aging Date: 2012-04-11 Impact factor: 4.673
Authors: Lisa Mosconi; Juha O Rinne; Wai H Tsui; Valentina Berti; Yi Li; Huiyu Wang; John Murray; Noora Scheinin; Kjell Någren; Schantel Williams; Lidia Glodzik; Susan De Santi; Shankar Vallabhajosula; Mony J de Leon Journal: Proc Natl Acad Sci U S A Date: 2010-03-15 Impact factor: 11.205
Authors: Valentina Berti; Lisa Mosconi; Lidia Glodzik; Yi Li; John Murray; Susan De Santi; Alberto Pupi; Wai Tsui; Mony J De Leon Journal: Neurobiol Aging Date: 2011-02-12 Impact factor: 4.673
Authors: Lisa Mosconi; John Murray; Wai H Tsui; Yi Li; Nicole Spector; Alexander Goldowsky; Schantel Williams; Ricardo Osorio; Pauline McHugh; Lidia Glodzik; Shankar Vallabhajosula; Mony J de Leon Journal: Neurology Date: 2014-02-12 Impact factor: 9.910
Authors: S Debette; P A Wolf; A Beiser; R Au; J J Himali; A Pikula; S Auerbach; C Decarli; S Seshadri Journal: Neurology Date: 2009-12-09 Impact factor: 9.910