Ontology of Variants of Cranial Structure and Malformations. Part I

Abstract

Annually severe congenital abnormalities occur in 1 of 33 newborns or about 125.000 live births in the United States and are the leading cause of infant mortality. Craniofacial anomalies account for about one-third of all abnormalities. The prevalence of human congenital malformations is an important characteristic of public health. According to the World Health Organization, the birth rate of children with cleft lip and palate is on average 1:750 newborns, which is 20-30% of all human malformations and 86% of maxillofacial malformations. They contribute significantly to infant morbidity and disability as well as millions of dollars in health care costs each year. Development of the human skull begins about 23-26 days after fertilization, when a multipotent population of cranial neural crest cells migrates from the dorsal part of the neuraxis to the embryonic head region, giving rise to the frontal bone and interparietal part of the occipital bone, while the rest of the cranial arch comes mainly from the mesoderm. A malformation is a deviation from the normal development of an organ or tissue. Among the causes are chromosomal abnormalities, single gene defects, teratogenic or multi-factor agents, that is, a combination of genetic and external factors; the smallest number of cases are idiopathic. Exogenous causes of human congenital abnormalities include: physical (mechanical, thermal, radiation); chemical (hypoxia, malnutrition, hormonal discordance, teratogenic poisons); biological (viruses, bacteria and their toxins, protozoa); mental factors. Endogenous causes are heredity (changes in hereditary structures, mutations); biological inadequacy of germ cells (endocrine disorders, “over-ripening” of germ cells); parents’ age. Congenital craniofacial abnormalities are caused by improper growth and/or development of the brain and facial parts of the skull and soft tissue. Craniofacial abnormalities affecting the skull include macrocephaly, microcephaly and unilateral deformities. Sometimes cranial sutures fuse too early and craniosynostosis occurs, which is accompanied by various cranial deformities. This leads to abnormal cranial development, which can cause dysmorphia, and in the most severe cases catastrophically affect brain development. Conclusion. Based on the analysis of the literature sources, an attempt has been made to summarize the existing information and classifications of congenital cranial abnormalities, as well as the interpretation of various anomalies of the brain and facial skull in alphabetic order. The most common stigmas and malformations of the skull bones are briefly characterized