Deposition of ubiquitin conjugates on inclusion bodies composed of protein aggregates is a definitive cytopathological hallmark of neurodegenerative diseases. We show that accumulation of ubiquitin on polyQ IB, associated with Huntington’s disease, is correlated with extensive depletion of nuclear ubiquitin and histone de-ubiquitination. Histone ubiquitination plays major roles in chromatin regulation and DNA repair. Accordingly, we observe that cells expressing IB fail to respond to radiomimetic DNA damage, to induce gamma-H2AX phosphorylation and to recruit 53BP1 to damaged foci. Interestingly ubiquitin depletion, histone de-ubiquitination and impaired DNA damage response are not restricted to PolyQ aggregates and are associated with artificial aggregating luciferase mutants. The longevity of brain neurons depends on their capacity to respond to and repair extensive ongoing DNA damage. Impaired DNA damage response, even modest one, could thus lead to premature neuron aging and mortality.

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Despite intensive study, most of the specific genetic factors that contribute to variation in human height remain undiscovered. We conducted a family-based linkage study of height in a unique cohort of very large nuclear families from a founder (Jewish) population. This design allowed for increased power to detect linkage, compared to previous family-based studies. Loci we identified in discovery families could explain an estimated lower bound of 6% of the variance in height in validation families. We showed that these loci are not tagging known common variants associated with height. Rather, we suggest that the observed signals arise from variants with large effects that are rare globally but elevated in frequency in the Jewish population.

Despite intensive study, most genetic factors that contribute to variation in human height remain undiscovered. We conducted a family-based linkage study of height in a unique cohort of very large nuclear families from a founder (Jewish) population. This design allowed for increased power to detect linkage, compared to previous family-based studies. We identified loci that together explain an estimated 6% of the variance in height. We showed that these loci are not tagging known common variants associated with height. Rather, we suggest that the observed signals arise from variants with large effects that are rare globally but elevated in frequency in the Jewish population.

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BackgroundFor the past 50 years, standard guidelines have recommended the use of sex-adjusted mid-parental height to predict a child's final height. Here, we studied the accuracy of this procedure.MethodsWe used height data in a cohort of 23 very large nuclear families (Mean = 11 adult children per family). We compared the actual final height of the children to their height predicted by the standard procedure, as well as to alternative height predictions that incorporate corrections of mid-parental height for age, sex, and regression to the mean.ResultsStandard mid-parental height explained 36% of the variance in children's heights, with a heritability of 74%, and children were on average 2.7 cm taller than predicted by their target heights. When we introduced a non-linear correction for the age of the parents, employed a multiplicative (rather than additive) correction for sex, and accounted for regression to the mean, the variance explained increased to 40%, heritability increased to 80%, and prediction bias was reduced from 2.7 cm to 0.14 cm (representing an improvement in prediction by half a standard deviation of the height distribution). We further measured the empirical distribution of heights of adult children around their predicted height. We describe how this distribution can be used to estimate the probability that a child's height is within the normal expected range.Conclusions and RelevanceBased on these observations, we propose an improved method for predicting children's target heights. Our procedure for determining whether the deviation of a child's projected height from the target height is in the normal range can be used to assess whether the child should be tested further for potential medical abnormalities.