Geographical distribution of fronto-ethmoidal encephalomeningocele.

Congenital malformations are among the most distressing diseases that affect mankind. Attempts to reconstruct the major anomalies have only limited success. Malformations affecting the brain are usually associated with some degree of mental deficiency. The recognition of causative agents such as infection, drugs, and genetic abnormalities offers some hope toward their prevention. Unfortunately the causative mechanism has been established in only a small proportion of human congenital malformations. Many investigations of the geographical distribution of anencephalus and defects of closure of the neural tube have been reported. Many of these reports, however, group all meningoceles of the spine and head together. The incidence of spina bifida shows a peculiar geographical pattern. The highest rates were found in Belfast (Stevenson, Johnston, Stewart, and Golding, 1966a) and Dublin (Coffey and Jessop, 1955), being 4*69 and 4 2 per 1,000 births respectively. Rates in western Europe (Book, 1951; Hohlbein, 1959), England and Wales (Malpas, 1937; Penrose, 1957; Carter, Lawrence, and David, 1967), and the United States (Schwidde, 1952; MacMahon, Pugh, and Ingalls, 1953; Harris and Steinberg, 1954; McIntosh et al., 1954) varied from 1 -2 to 2 8 per 1,000 births. Lower incidences were found in eastern and southern Europe (Candido, 1951; Stevenson et al., 1966a; Czeizel and R6v6sz, 1970), South and Central America (Stevenson et al., 1966a), Australia and New Zealand (Collmann and Stoller, 1962; Stevenson et al., 1966a; Howie and Phillips, 1970), Africa (Simpkiss and Lowe, 1961; Khan, 1965; Stevenson et al., 1966a; Gupta as quoted by Odeku, 1967), and Asia (Neel, 1958; Stevenson et al., 1966a; Kolah, Master, and Sanghvi, 1967; Saifullah, Chandra, Pathak, and Dhall, 1967) with the exception of a few isolated places such as Alexandria in Egypt and perhaps Chandigarh in India. In western countries, spinal and occipital meningoceles are common, but in Thailand we have found an exceptionally high incidence of encephalomeningocele in the anterior part of the head (see Figures 1 and 2). This fact, which suggests that meningoceles do not comprise a homogeneous group, led us to examine the geographical distribution of this group of malformations.