Bipolar disorder (BD) is a severe psychiatric disorder associated with structural and functional brain abnormalities, some of which have been found in unaffected relatives as well. In this study, we examined the potential role of decreased fractional anisotropy (FA) as a BD endophenotype, in adolescents at high risk for BD.

We included 15 offspring of patients with BD, 16 pediatric BD patients, and 16 matched controls. Diffusion weighted scans were obtained on a 3T scanner using an echo-planar sequence. Scans were segmented using FreeSurfer.

Our results showed significantly decreased FA in six brain areas of offspring group; left superior temporal gyrus (LSTG; P < .0001), left transverse temporal gyrus (LTTG; P = .002), left banks of the superior temporal sulcus (LBSTS; P = .002), left anterior cingulum (LAC; P = .003), right temporal pole (RTP; P = .004) and left frontal pole (LFP; P = .017). On analysis, LSTG, LAC, and RTP demonstrated a potential to be an endophenotype when comparing all three groups. FA values in three regions, LBSTS, LTTG, and LFP were increased only in controls.

Our findings point at decreased FA as a possible endophenotype for BD, as they were found in children of patients with BD. Most of these areas were previously found to have morphological and functional changes in adult and pediatric BD, and are thought to play important roles in affected domains of functioning. Prospective follow up studies should be performed to detect reliability of decreased FA as an endophenotype and effects of treatment on FA.

双相情感障碍 (BD) 是一种严重的精神疾病，与大脑结构和功能异常有关，其中一些也在未受影响的亲属中发现。在这项研究中，我们检查了分数各向异性 (FA) 降低作为 BD 内表型在 BD 高危青少年中的潜在作用。

我们纳入了 15 名 BD 患者的后代、16 名儿童 BD 患者和 16 名匹配的对照组。使用回波平面序列在 3T 扫描仪上获得扩散加权扫描。使用 FreeSurfer 对扫描进行分段。

我们的结果显示后代组六个脑区的 FA 明显减少；左侧颞上回 (LSTG; P  < .0001)、左侧颞横回 (LTTG; P  = .002)、左侧颞上沟岸 (LBSTS; P  = .002)、左侧前扣带回 (LAC; P  = .003)、右颞极 (RTP; P  = .004) 和左额极 (LFP; P  = .017)。经分析，LSTG、LAC 和 RTP 在比较所有三组时显示出成为内表型的潜力。LBSTS、LTTG 和 LFP 三个区域的 FA 值仅在对照组中增加。

我们的研究结果表明 FA 减少可能是 BD 的一种内表型，因为它们在 BD 患者的儿童中被发现。大多数这些区域以前被发现在成人和儿童 BD 中有形态和功能变化，并且被认为在受影响的功能区域中发挥重要作用。应进行前瞻性随访研究，以检测 FA 减少作为内表型的可靠性以及治疗对 FA 的影响。