Abstracts of Selected Articles
(The following abstracts from the July and August 1964 issues of BIRTH DEFECTS are reprinted with the permission of the National Foundation-March of Dimes.)
The Etiology Of Congenital Malformations (Part 2). (In French) J. Genet. Hum. 12 (3-4):214-239, Dec. 1963.
Sayegh, C. (Dept. Gynecol. Obstet., Univ. Geneva, Switzerland.)
A survey of 115 malformed and 190 normal children over an unspecified period indicates a greater frequency of defect among males, especially given high parental age. Birth weight below 2500 g was found for one quarter of all defectives, while a 35% mortality contrasts with 1.5% for the normal sample.
The frequency of malformation is placed at 1.2% of all births, and 15.6% of all perinatal and infant mortality in Switzerland is linked to congenital deficit. Mongolism accounts for 6%, facial deformity 10.5%, CNS defects 15%, cardiovascular anomalies 7%, urogenital abnormality 13%, limb malformations 24.5%, miscellaneous 10.5%, and multiple 13.5%.
Parity, toxemia, placental infarct, threat of abortion, but not maternal anemia or vomiting, were found to vary directly with malformation risk, and were significantly higher in the defective than in the control group. Maternal infections, including German measles and influenza, were equally distributed over both groups, while psychic stress (as a consequence of vehicular accidents, for example) was insignificantly less in the control group and results of radiation exposure were indeterminate. However, anomalies in amniotic fluid, due principally to hydramnios, were significantly higher in the defective group.
General health ratings are also poorer among the defectives, but economic status is not significantly involved. Nutritional variations either could not be properly evaluated or showed no group differences. Psychic trauma, as emotional shock, terror, chronic anxiety, was significantly lower in the control group. All such environmentally evoked abnormalities are phenocopies of the hereditary types, and combined forms are said to dominate clinically. Certain treatment and prophylactic problems are also discussed.
Genetic And Environmental Factors In The Etiology Of Congenital Dislocation Of The Hip. Clin. Orthop. 33:119-128, Mar.-Apr. 1964.
Carter, C. O. and Wilkinson, J. A. (Clin. Genet. Res. Unit, Inst. Child Health, London, England.)
Evidence that only 40% of monozygotic co-twins also have congenital dislocation of the hip (CDH) suggests environmental influence, while data that monozygotes are significantly more affected than dizygotic co-twins - perhaps by a factor of 10 - shows genetic control.
The revised incidence of CDH is about four per thousand, based on the Swedish experience, although swaddling or other ethnically accepted techniques of early pediatric hip extension and adduction invite higher frequencies.
About five to eight females are affected for every male, or 1:4000 male and 1:600 female live births, which might result from a normal temporary hormonal generalized joint laxity in the fetal or early neonatal female.
Although definitive pedigree studies are lacking, family concentration is undeniable in all series reported. In the authors' survey 12 of 210 sibs were affected, including 7% sisters and 4% brothers, in which six of 39 sibs of male index patients were affected. In both offspring and sibs the defect is about 30 times the population incidence. A dominant mutant gene of low manifestation rate or multifactorial inheritance must be involved. Acetabular dysplasia, a multifactorial non-sex-linked factor, and generalized laxity of the articular ligaments (the male counterpart of hormonal laxity in girls) which is possibly due to dominant mutant inhibition of the liver to destroy estrogens, are the two complementary mechanisms expressing the genetic predisposition. Four typical families are illustrated.
The most important environmental factor is the intra-uterine breech posture with hips flexed, knees extended, and limbs laterally rotated. Experimental confirmation has been obtained in rabbits provided the ligaments are first relaxed by estrone or progesterone.