Neurocristopathies

Abstract

Interest, indeed fascination, with developmental abnormalities stretches back at least to the Neolithic period. A sculpture of a two-headed individual dated 6500 BC was excavated from southern Turkey, while cuneiform characters on seventh century BC clay tablets discovered in the Royal Library at Nineveh record 62 different human malformations known to the Babylonians. Syndromes such as Treacher Collins were depicted in Mexican statues as early as AD 2. Given such extended interest, we might expect that all possible syndromes would have been identified long ago. But syndromology is not dead; one or more new syndromes are described somewhere in the world each week. Syndromes involving neural tube defects (Table 11.1) are second only to heart defects as a source of perinatal mortality in humans, accounting for some 15% of perinatal deaths in the United Kingdom alone. Fortunately, folic acid has proven to be very effective in preventing as many as 70% of human neural tube defects, such as spina bifida, to which defective neural crest contributes. Because of the relationship between ultraviolet light and folic acid, melanin may also protect against neural tube defects.¹