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目的探索儿童青少年脑灰白质容积比、灰质全脑容积比、白质全脑容积比是否为稳定内表型,作为儿童脑发育的关键内表型指标。方法采用横断面设计双生子法,以学籍登记为线索募集12~18岁的双生子,采集静脉血液标本提取DNA,进行卵型鉴定。采用中国修订版-韦氏儿童智力量表进行智商测定。用3.0T MRI(GE)对双生子对进行头颅结构扫描,采集全脑166层矢状位图像。结果①最终符合条件58对双生子成功提取DNA,卵型鉴定结果显示:同卵双生子31对,异卵双生子27对;②灰质容积、白质容积、脑脊液容积、全脑容积、灰白质容积比、灰质全脑容积比、白质全脑容积比在MZ间均呈正相关(P<0.01);DZ除灰质全脑容积比及脑脊液容积呈正相关(P<0.05)外,其余5项差异无统计学意义(P>0.05);Holzinger方法估计灰白质容积比遗传度0.828,灰质全脑容积比遗传度为0.596,白质全脑容积比遗传度为0.741。结论为克服个体脑容积差异而候选的3个容积比中,无脑脊液容积影响的灰白质容积比有较高遗传度,说明灰白质容积比有相对稳定的遗传基础,可以作为儿童青少年脑发育的内表型指标。
Objective To explore the relationship between brain gray matter volume ratio, whole brain volume ratio of gray matter and whole brain volume ratio of white matter in children and adolescents as a stable internal phenotype, as the key endophenotype indicators of brain development in children. Methods The twins method was adopted to design a cross-sectional design. Twelve-year-old twins (12-18 years old) were recruited with the enrollment of students’ registers. Blood samples were collected for DNA extraction and egg identification. China’s revised version - Webster Children’s Intelligence Scale for IQ determination. A 3.0T MRI (GE) was used to scan the twins of the twins and the 166 layers of sagittal images of the whole brain were collected. RESULTS ① The DNA was successfully extracted from the twins according to the final conditions. The results of egg type identification showed that there were 31 pairs of identical twins and 27 pairs of fraternal twins. ② The gray matter volume, white matter volume, cerebrospinal fluid volume, total brain volume, (P <0.01). There was no significant difference in the brain volume ratio of DZ between gray matter volume and cerebrospinal fluid volume (P <0.05) (P> 0.05). The Holzinger method estimated that the heritability of gray matter was 0.828, the heritability of gray matter was 0.596, and the heritability of white matter was 0.741. CONCLUSION: To overcome the difference of individual brain volume, among the three candidate volume ratios, there is a high heritability of gray matter volume ratio without cerebrospinal fluid volume, indicating a relatively stable genetic basis of gray matter volume ratio and can be used as brain development of children and adolescents Internal phenotype indicators.