Center for Anatomical Sciences, University of North Texas Health Science Center, Fort Worth, TX, USA.
Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN, USA.
FASEB J. 2020 Aug;34(8):10850-10859. doi: 10.1096/fj.202000715R. Epub 2020 Jun 27.
Osteogenesis imperfecta (OI) is a skeletal disorder characterized by the impaired synthesis of type I collagen (Col1). This study tests the hypothesis that the craniofacial phenotype of severe OI is linked to an overall reduction in body size. 3D landmark data were collected from µCT scans of adult OIM and wild-type (WT) mice and used to calculate centroid sizes (CS) and interlandmark distances (ILDs). To remove the effect of body size, ILDs were scaled against craniomandibular lengths and CS. Mann-Whitney U tests were used to compare CS and absolute/scaled ILDs between genotypes. OIM mice are smaller than their WT littermates in body mass, craniomandibular CS, and absolute ILDs including skull, basicranial, palatal, mandibular, and toothrow lengths. When linear distances are scaled to CS, OIM mice have a relatively short midface, short nasal bones, tall mandibular corpora, and long mandibular toothrows. Results underscore the importance of size and scaling in morphometric analyses. The deleterious effect of Col1 mutations on global skeletal dimensions combined with localized morphometric changes may underlie the facial phenotype seen in human patients with severe OI. Attempts to identify these localized changes should first account for the restricted growth and small body sizes present in individuals with OI.
成骨不全症（OI）是一种骨骼疾病，其特征是 I 型胶原蛋白（Col1）合成受损。本研究检验了这样一个假设，即严重 OI 的颅面表型与整体体型减小有关。从成年 OIM 和野生型（WT）小鼠的µCT 扫描中收集了 3D 地标数据，并用于计算质心大小（CS）和地标间距离（ILDs）。为了去除体型的影响，ILDs 按颅颌长度进行了缩放和 CS。使用 Mann-Whitney U 检验比较了基因型之间的 CS 和绝对/缩放的 ILD。与 WT 同窝仔相比，OIM 小鼠的体重、颅颌 CS 和绝对 ILD（包括颅骨、基颅、腭、下颌和牙弓长度）较小。当线性距离缩放到 CS 时，OIM 小鼠的中面部相对较短，鼻骨较短，下颌体较高，下颌牙弓较长。研究结果强调了大小和缩放在形态计量分析中的重要性。Col1 突变对全身骨骼尺寸的有害影响加上局部形态计量变化，可能是严重 OI 患者面部表型的基础。试图识别这些局部变化时，应首先考虑到 OI 患者的生长受限和体型较小。
