Lumbo-sacral malformations and spina bifida occulta in a group of proto-historic Modoc Indians

A complex lumbo-sacral malformation has been found in an unusually high frequency in a group of proto-historic Modoc Indians. Following a short review of vertebral abnormalities in general, the condition is described. It is suggested tentatively that inbreeding might be in part responsible for the high frequency.     

A mouse model for neural tube defects: the curtailed (Tc) mutation produces spina bifida occulta in Tc/+ animals and spina bifida with meningomyelocele in Tc/t

Curtailed (Tc), a dominant mutation on mouse chromosome 17, causes a tailless phenotype and occasional hindlimb paralysis in heterozygotes. Histologically, Tc/+ embryos show a variety of abnormalities including budding and ventral duplication of the developing spinal cord, duplication and intermittent absence of the notochord, and partial or complete absence of bony vertebrae, all posterior to midliver level. When Tc is heterozygous with t-haplotypes that contain the "tail interaction factor," tct, the phenotype is more severe, and a dorsal blood blister exists in the lumbosacral area. Our microscopic observations reveal that Tc/tw5 mice have a lumbosacral spina bifida with meningomyelocele. This results from the absence of bony vertebrae, extensive thinning of the dermis dorsally, and the rupturing of the previously closed neural tube, probably by increased cerebrospinal fluid (CSF) pressure on the necrotic, attenuated roof plate. Thinning of the roof plate, which facilitates the rupturing of the spinal cord, is not observed in Tc/+, which suggests that this phenomenon is associated with the interaction of Tc with the t-allele. Later in the development of Tc/tw5 embryos, adjacent blood vessels are ruptured, resulting in hemorrhage into the CSF space to give the external appearance of a blood blister. Tc/+ mice also show an absence of bony vertebrae dorsally in the lumbosacral region, but they lack the dorsal blood blister, and the dermal layer overlying the bony defect retains its normal thickness; these observations describe a spina bifida occulta.     

Anthropological study on spina bifida in the Community of Madrid

The incidence of spina bifida in the Community of Madrid (Spain) has been assessed during an eleven-year period, since 1970 to 1980: 0.37 per 1,000 newborns over a total of 272,332 newborns, dead and alive, of simple births. The sex ratio at birth was 94. Maternal variables have been studied (maternal age, menarche, parity, etc.), obstetric variables (number of abortions, medication during pregnancy, etc.) and also neonatal variables (weight, gestational age, state at birth, etc.). Seasonal variations were observed.     

The sex ratio in spina bifida

It is shown that the well known excess of females in spina bifida children is statistically significant when they are compared with (a) the general population and (b) their sibs.Although there is a small excess of males amongst the sibs this is not statistically significant when compared with the general population and when all the children in these families are considered they appear to have a sex ratio very similar to that general population. The sibs of the parents of spina bifida children show a statistically significant excess of females.These findings are discussed with particular reference to the genetics of spina bifida.     

Anencephalus and spina bifida: An ecological approach

The ecological approach to the etiology of disease involves consideration of the complex interactions of factors related to the host, agent, and environment. Although the ecological approach was developed with regard to infectious diseases, this article suggests its application as a meaningful approach to understanding the etiology of anencephalus and spina bifida. Host, agent, and environmental factors thought to be important in the development of these malformations are discussed. Translation of this conceptual approach into a testable model is needed.Presented in part at the symposium, Anthropology and Medical Education, 44th Annual Meeting of the American Association of Physical Anthropologists, Denver, Colorado, April 9–12, 1975.     

Sex ratio in spina bifida and anencephaly

Timson's (1969, 1970) three locus model for the determination of anencephaly and spina bifida is examined, and it is concluded that observed population incidences of these conditions do not fit the model. A consideration is presented of the relevance of such models to the aetiology of multifactorial disease.     

Incidence of anencephalus and spina bifida in Greece

A cross-sectional national survey of 11,048 births in the whole of Greece in April 1984 identified 7 cases of anencephalus and 9 of spina bifida. There was thus an incidence of 1.45 neural tube defects per 1,000 total births. This is the first geographically defined population study from southern Europe. In comparison with hospital-based data from the 2 countries on its borders, the Greek rates are rather similar to those of Yugoslavia but much lower than reports from Turkey.