Opitz J M, Holt M C
Department of Medical Genetics, Shodair Children's Hospital, Helena, Montana 59604.
J Craniofac Genet Dev Biol. 1990;10(2):175-204.
Microcephaly is defined as an occipito-frontal head circumference (OFC) 2 or more standard deviations below the mean for age and sex using the new Roche et al. [Pediatrics 1987;79:706-712] charts, and corrected for parental OFC by the method of Weaver and Christian [J Pediatr 1980;96:990-994]. "Relative" microcephaly, i.e., a small head on a small child, may be associated with a much better intellectual prognosis than absolute microcephaly, although the average IQ of children with absolute microcephaly ascertained in a normal school system is normal when compared with that of appropriate control children. "Primary" microcephaly means an abnormal OFC at birth (corrected for gestational age and length), and "secondary" microcephaly a normal birth OFC with later, acquired microcephaly due to deceleration of brain growth reflecting infection, trauma, intoxication, metabolic disease, the Rett syndrome, or a true CNS degenerative disease. Some cases of syndromal microcephaly may be associated with normal intelligence including some "primordial dwarfs," children with Dubowitz syndrome, FAS, mild SC-Roberts syndrome, and an occasional Brachmann-de Lange individual. The nosology of (syndromal) microcephaly is extraordinarily complex and requires the assistance of special library resources and information retrieval expertise. At a minimum, it requires McKusick's Catalog of Mendelian Inheritance in Man (MIM); however, we find that our work is greatly enhanced by recently developed electronic databases such as MIM-online (OMIM), POSSUM, SYNDROME, and MEDLINE, as well. Three groups of syndromal and non-syndromal microcephaly are discussed selectively in order to illustrate the marvels of pleiotropy in human development and its abnormalities and the difficulties encountered in splitting and lumping entities with overlapping manifestations.
使用新的罗氏等人[《儿科学》1987年；79:706 - 712]图表，枕额头围（OFC）低于年龄和性别的均值2个或更多标准差，并按照韦弗和克里斯蒂安的方法[《儿科学杂志》1980年；96:990 - 994]根据父母的OFC进行校正。“相对”小头畸形，即小孩头部较小，与绝对小头畸形相比，其智力预后可能要好得多，尽管在正常学校系统中确诊的绝对小头畸形儿童的平均智商与适当的对照儿童相比是正常的。“原发性”小头畸形是指出生时OFC异常（根据胎龄和身长校正），“继发性”小头畸形是指出生时OFC正常，后来由于脑生长减速导致小头畸形，脑生长减速反映了感染、创伤、中毒、代谢疾病、雷特综合征或真正的中枢神经系统退行性疾病。一些综合征性小头畸形病例可能与正常智力相关，包括一些“原始侏儒”、杜波维茨综合征患儿、胎儿酒精综合征患儿、轻度SC - 罗伯茨综合征患儿以及偶尔的布腊克曼 - 德朗热综合征个体。（综合征性）小头畸形的疾病分类极其复杂，需要特殊图书馆资源和信息检索专业知识的帮助。至少，它需要麦库西克的《人类孟德尔遗传目录》（MIM）；然而，我们发现最近开发的电子数据库，如在线MIM（OMIM）、POSSUM、SYNDROME和MEDLINE，也极大地促进了我们的工作。为了说明人类发育及其异常情况中多效性的奇妙之处，以及在对表现重叠的实体进行分类和归纳时遇到的困难，我们有选择地讨论了三组综合征性和非综合征性小头畸形。
