Age at onset of multiple sclerosis may be influenced by place of residence during childhood rather than ancestry

Multiple sclerosis (MS) most commonly affects individuals of Northern European descent who live in countries at high latitude. The relative contributions of ancestry, country of birth and residence as determinants of MS risk have been studied in adult MS, but have not been explored in the pediatric MS population. In this study, we compare the demographics of pediatric- and adult-onset MS patients cared for in Toronto, Ontario, Canada, a multicultural region. The country of birth, residence during childhood, and ancestry were compared for 44 children and 573 adults. Our results demonstrate that although both the pediatric and adult cohorts were essentially born and raised in the same region of Ontario, Canada, children with MS were more likely to report Caribbean, Asian or Middle Eastern ancestry, and were less likely to have European heritage compared with individuals with adult-onset MS. The difference in ancestry between the pediatric and adult MS cohorts can be explained by two hypotheses: (1) individuals raised in a region of high MS prevalence, but whose ancestors originate from regions in which MS is rare, have an earlier age of MS onset, and (2) the place of residence during childhood, irrespective of ancestry, determines lifetime MS risk -- a fact that will be reflected in a change in the demographics of the adult MS cohort in our region as Canadian-raised children of recent immigrants reach the typical age of adult-onset MS.     

4α-phorbol 12,13-didecanoate activates cultured mouse dorsal root ganglia neurons independently of TRPV4

Background and Purpose

The Ca²⁺-permeable cation channel TRPV4 is activated by mechanical disturbance of the cell membrane and is implicated in mechanical hyperalgesia. Nerve growth factor (NGF) is increased during inflammation and causes mechanical hyperalgesia. 4α-phorbol 12,13-didecanoate (4αPDD) has been described as a selective TRPV4 agonist. We investigated NGF-induced hyperalgesia in TRPV4 wild-type (+/+) and knockout (–/–) mice, and the increases in [Ca²⁺]_i produced by 4αPDD in cultured mouse dorsal root ganglia neurons following exposure to NGF.

Experimental Approach

Withdrawal thresholds to heat, von Frey hairs and pressure were measured in mice before and after systemic administration of NGF. Changes in intracellular Ca²⁺ concentration were measured by ratiometric imaging with Fura-2 in cultured DRG and trigeminal ganglia (TG) neurons during perfusion of TRPV4 agonists.

Key Results

Administration of NGF caused a significant sensitization to heat and von Frey stimuli in TRPV4 +/+ and –/– mice, but only TRPV4 +/+ mice showed sensitization to noxious pressure. 4αPDD stimulated a dose-dependent increase in [Ca²⁺]_i in neurons from +/+ and –/– mice, with the proportion of responding neurons and magnitude of increase unaffected by the genotype. In contrast, the selective TRPV4 agonist GSK1016790A failed to stimulate an increase in intracellular Ca²⁺ in cultured neurons. Responses to 4αPDD were unaffected by pretreatment with NGF.

Conclusions and Implications

TRPV4 contributes to mechanosensation in vivo, but there is little evidence for functional TRPV4 in cultured DRG and TG neurons. We conclude that 4αPDD activates these neurons independently of TRPV4, so it is not appropriate to refer to 4αPDD as a selective TRPV4 agonist.     

Further evidence for linkage of bipolar disorder to chromosomes 6 and 17 in a new independent pedigree series

Greenwood TA, Nievergelt CM, Sadovnick AD, Remick RA, Keck PE Jr, McElroy SL, Shekhtman T, McKinney R, Kelsoe JR. Further evidence for linkage of bipolar disorder to chromosomes 6 and 17 in a new independent pedigree series. Bipolar Disord 2012: 14: 71–79. © 2012 The Authors. Journal compilation © 2012 John Wiley & Sons A/S. Objectives: We have previously reported the results of a linkage analysis of bipolar disorder in an initial set of 20 pedigrees ascertained through collaboration among three sites. We now report the results of our genome‐wide linkage analysis in an independent sample of 34 pedigrees segregating bipolar disorder. Methods: Families were ascertained through a bipolar I or II disorder proband for the presence of bipolar I disorder, bipolar II disorder, or recurrent major depression in at least two other family members. A total of 440 markers at an average spacing of 8 cM were genotyped in 229 family members using fluorescent methods. Results: Initial nonparametric analyses of chromosomes 6 and 17 provided evidence for a modest replication of linkage to these chromosomes previously reported in other studies. Additional analyses using multipoint parametric methods provided further evidence to support the 6q25 region with a heterogeneity logarithm of odds score of 3.28. Evidence from two‐point parametric analyses also provides a modest replication of our previous findings of linkage to the 23 cM region of chromosome 22q13 in our original University of California, San Diego sample of 20 families and 57 families from the National Institute of Mental Health bipolar disorder sample. Conclusions: Our results suggest replication of some reported linkage peaks, such as 6q25 and 17p12; however, other peaks from our own previous study, such as 5p15, 13q32, and 22q13, were either not replicated or were only modestly replicated in these analyses.     

希—内学习能力测验在中国聋儿中使用的信度和效度

采用经部分修改的希－内学习能力测验（Ｈ－ＮＴＬＡ）量表对全国２１个省、市、自治区１７５８名３－１７岁聋儿逐人测试。样本人群地区分布、家长职业构成与１９９０年全国人口普查资料一致。１７５８名聋儿智商呈现正态分布（ｇ１＝０．０１１Ｐ＞０．０５，ｇ２＝０．０５８Ｐ＞０．０５）。测试员间信度系数０．９８１（Ｎ＝２４），复测信度０．８４１（Ｎ＝１３６），分半信度０．９２７（３－８岁）及０．８５４（９－１７岁）。各分测验得分随年龄增加而增加，小年龄组增加明显，大年龄组增加缓慢。各分测验之间、各分测验和总离差智商之间大多数相关系数有显著统计学意义。智商与学习成绩（语文及数学）相关系数０．２０８（Ｐ＜０．０１Ｎ＝２２４），与教师评语等级相关系数０．４４（Ｐ＜０．０５ｄｆ＝１６），表明经修订的Ｈ－ＮＴＬＡ量表适用于中国听力语言障碍人群进行智力评定。     

Linkage studies suggest a possible locus for bipolar disorder near the velo-cardio-facial syndrome region on chromosome 22

Velo-cardio-facial syndrome (VCFS) is a congenital anomaly characterized by multiple dysmorphisms, cleft palate, cardiac anomalies, and learning disabilities, that results from a microdeletion of chromosome 22q11. An increased prevalence of psychiatric illness has been observed, with both schizophrenia and bipolar disorder commonly being diagnosed. For these reasons, the VCFS region is an interesting candidate region for bipolar disorder. We examined this region in 17 bipolar families from three populations: 13 families from the general North American population (University of California, San Diego/University of British Columbia, UCSD/UBC), three larger families from New York, and a portion of Old Order Amish pedigree 110. Three microsatellite markers spanning 13 cM around the VCFS region were genotyped in all the families. A maximum lod score of 2.51 was obtained in the UCSD/UBC families under a dominant model at D22S303. In the combined family set, maximum lod scores of 1.68 and 1.28 were obtained at this marker under dominant and recessive models, respectively. Four additional markers were subsequently typed in selected positive families, and yielded positive lods at 6 of 7 markers spanning 18 cM in this region. Nonparametric, multipoint analyses using the affected pedigree member (APM) method also yielded suggestive evidence for linkage in both the UCSD/UBC family set (P = 0.0024) and in the combined families (P = 0.017). Affected sib-pair analyses were similarly positive in the UCSD/UBC families (P = 0.017), and in the combined families (P = 0.004). These results are suggestive of a possible locus for bipolar disorder near the VCFS region on chromosome 22. Am. J. Med. Genet. 74:121–128, 1997. © 1997 Wiley-Liss, Inc.