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.     

Incidence of occult lumbro-sacral spina bifida in parents of children with spina bifida (concerning 80 pairs of parents with affected children)

Authors examined 80 pairs of parents with affected children with spina-bifida. They compared the incidence of spina-bifida occulta in parents and in 211 controls. The conclusion is: there is no increased incidence of spina-bifida occulta in parents of spina-bifida.     

Apparently monogenic inheritance of anencephaly and spina bifida in a kindred

Summary Anencephaly and/or spina bifida has been observed in 5 of 8 children from 2 related families. The fathers of both families were brothers and had married 2 sisters. By further investigation they could be shown to be third degree cousins to their marriage partners. No malformations were known among further relatives. The family pattern suggests autosomal recessive inheritance of anencephalus and/or spina bifida in this family, although it could not be excluded, that genetically determined intrauterine factors were of importance.

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Zusammenfassung In 2 verwandten Familien einer Sippe hatten 5 von 8 Kindern Anencephalie und/oder Meningocele. Die Väter beider Familien waren Brüder, die Mütter Schwestern. Das Studium der Kirchenbücher ergab, daß die Ehepartner außerdem Vettern und Basen dritten Grades waren. Weder den Eltern noch dem Hausarzt waren bei weiteren Verwandten Fehlbildungen ähnlicher oder anderer Art bekannt. Der Stammbaum macht autosomal-recessiven Erbgang der Schulßstörung des Neuralrohres in dieser Familie sehr wahrscheinlich, es kann jedoch nicht mit voller Sicherheit ausgeschlossen werden, daß erblich bedingte intrauterine Faktoren entscheidend waren.

     

Prenatal diagnosis of 4 cases of spina bifida in mothers treated with valproate

The potential risk of spina bifida (SB) after fetal exposure to Valproate led the authors to apply the following protocol: in case of first trimester exposure to Valproate, prenatal diagnosis is offered and consists of both amniotic fluid examination and fetal ultrasound to detect open spina bifida. In the period 1983 to June, 1986, this program allowed early detection of three cases of SB and pregnancy termination. Another case escaped the programme: neural tube defect was detected lately and the child had to be operated upon. These four cases of SB underline the necessity of prenatal diagnosis with combined use and confrontation of ultrasound examination and biochemical amniotic fluid tests.     

Segregation of HLA haplotypes in a family with infants having spina bifida]

The search for HLA association in spina bifida is particularly interesting since this condition can be associated with the effect of the T locus in mice. Gene and haplotype frequencies in 32 unrelated patients suffering from spina bifida were studied. Patients and families were examined clinically and radiologically. A high frequency of spina bifida occulta and other vertebral abnormalities was found suggesting genetic determinism but no evidence of linkage with HLA genes or haplotypes was found.     

Sleep problems, chronotype, and diurnal preferences in children and adults with spina bifida

Spina bifida meningomyelocele (SBM) is a neural tube defect that involves dysraphism of the spinal cord and extensive reorganization of the brain. The authors assessed the relationship between chronotype, diurnal preferences, and sleep problems in individuals with SBM and healthy controls. Although individuals with SBM showed the characteristic decelerating quadratic relationship between age and chronotype, the curve was displaced, peaking at a younger age in controls compared with SBM (23.4 vs. 29.2 years). Groups did not differ in morningness-eveningness preferences. Individuals with SBM endorsed more sleep problems than controls. Further examination of the relationship between entrainment and sleep in SBM is warranted.     

Risk factors in the prevalence of anencephalus and spina bifida in New Zealand

This paper presents results from an epidemiological study on the 51 anencephalus and 53 spina bifida cases in the 1978 New Zealand birth cohort. Multiple sources were used in the ascertainment, and the prevalence rates were 0.98 and 1.02 per 1,000 total births, respectively. No association was found with the traditional indicators of the effect of environmental factors: maternal age, social class, nuptiality, month of birth, or estimated month of conception. Males comprised 41% of anencephalus and 36% of spina bifida cases; the prevalence was higher in the non-Maori than in the Maori population. New Zealand-born mothers appear to have a much lower risk of spina bifida, but not anencephaly, than those born in England/Scotland. The rate for the latter population was within the range of a number of UK-based studies. As the bloodstock of New Zealand whites has been predominantly derived from the UK population, and as New Zealand is a low prevalence area, this suggests that the higher risk for these women is likely to be attributable to factors present in their birthplace but absent in New Zealand. These findings provide further evidence that the epidemiologic patterns of anencephalus and spina bifida in low-prevalence areas are at variance with those in high-prevalence areas, such as the United Kingdom. They also support the hypothesis that the contrast in rates between high- and low-prevalence areas is a reflection of the impact of environmental factors in high-prevalence areas on the "background" or baseline frequency of anencephalus and spina bifida found in low-prevalence areas.     

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.