Anticipation On Age At Onset In Kindreds With Hereditary Attrv30m Amyloidosis From The Majorcan Cluster

Background Hereditary transthyretin amyloidosis (ATTRV30M) is a rare disease caused by amyloid deposition and characterized by a heterogeneous presentation. Anticipation (AC) is described as the decrease in age at onset (AO) within each generation. Our aim was to study AC in a large number of ATTRV30M kindred from Majorca (Spain), and gain further insight into parent-of-origin effects. Methods In a cohort of 262 subjects with ATTRV30M amyloidosis belonging to 51 families, we found 37 affected pairs. AO is defined as the age at the first symptom and AC (parent's age at disease onset minus that of the offspring) were calculated. Chi-square test, independentt-test and pairedt-test were used for comparisons between groups. Association between AO of parents and offsprings were assessed by Pearson's correlation coefficient. Results Offspring mean AO was 16 years lower than that of the parents (p < .001) regardless of the sex of the parents and the offspring. AC occurred in 31 out of the 37 pairs, with no differences related to the sex of parents or offspring. There was a moderate correlation (r = 0.49;p < .001) between AO of the parents and that of the offsprings. Conclusion AC was no uncommon in our cohort, and AO tended to decrease in successive generations.