Cowie V A
Department of Psychological Medicine, University of Wales College of Medicine, Ely Hospital, Cardiff.
J Ment Defic Res. 1987 Sep;31 ( Pt 3):229-33. doi: 10.1111/j.1365-2788.1987.tb01365.x.
Microcephaly is a clinical sign rather than a nosological entity. It may even represent the extreme of normal variation. In pathological cases, it is always caused by an interruption of the neurobiologic processes of induction and cellular migration, or by a catastrophic insult to the central nervous system. The prime cause of this may be environmental or genetic. There is strong evidence for genetic heterogeneity, even among cases of 'true' or 'primary' microcephaly. Various taxonomies for the classification of microcephaly are discussed, taking into account environmental causation and various genetic mechanisms.
小头畸形是一种临床体征而非病种实体。它甚至可能代表正常变异的极端情况。在病理病例中，它总是由诱导和细胞迁移的神经生物学过程中断，或由中枢神经系统的灾难性损伤引起。其主要原因可能是环境因素或遗传因素。即使在“真性”或“原发性”小头畸形病例中，也有强有力的证据表明存在遗传异质性。本文讨论了小头畸形分类的各种分类法，同时考虑了环境病因和各种遗传机制。
