Decreased developmental stability as assessed by fluctuating asymmetry of morphometric traits in preterm infants

Abstract

Fluctuating asymmetry (FA) of 8 morphometric traits was studied in 113 preterm infants (26-36 wk of gestation), 103 term infants (37-41 wk), and their respective parents. With 3 different measures of FA, the highest values were obtained from extremely preterm infants (26-29 wk), and the lowest from the group of term infants. The estimates of FA values among parents, particularly mothers, showed a similar, albeit less pronounced, trend. Multiple regression analysis of individual mean FA values, calculated in infants for the 8 studied bilateral traits, documented a significant inverse correlation with gestational age and with the health status of the infants and their mothers, as well as a positive correlation with the mothers' mean FA values.

Historical perspective on developmental concepts and terminology

“…Causal concerns were always on top of the agenda, that is: to what degree might single transverse creases, fifth finger clinodactyly, distal palmar axial triradii, radial loops on digits 4 and 5 (all minor anomalies, per se of trivial concern to the infant, parents totally oblivious to them) be a miner's canary for something far more serious, for example, Down syndrome? The Israeli approach ultimately was the most fruitful, being extended to an analysis of fluctuating asymmetry (FA) as an exquisitely sensitive indicator of developmental stability/instability of anthropomorphic traits not grossly evident to the clinicians as a "minor anomaly," say in a premature infant [Livshits and Kobyliansky, 1991;Livshits et al, 1998]. Since apparent minor anomalies may be nothing more than a normal variant in a family but unusual for the population, the phenotype analysis of such findings in an infant at birth requires first-class epistemological judgment, preferably an analysis of family resemblance if the matter warrants concern.…”

“…We all have had similar experiences in individuals with small and contralateral absent thumb or, small/triphalangeal thumb, small auricle/microtia-anotia, small/absent upper lateral incisors/broad/bifid upper lateral incisors, brother with broad/sister with cleft xiphisternum, etc. Thus, it seems appropriate to propose a hypothesis: Bilaterally symmetrical structures of the human body (which are conjoint MZ twins) are subject to fluctuating asymmetry [FA, Ludwig, 1932van Valen, 1962;Livshits et al, 1998;Opitz and Utkus, 2001]: random differences between the two sides of quantitative traits. These increase in parallel to the decreased buffering ability of an organism, thus, are a measure of developmental (in)stability: The greater the FA the less the developmental stability.…”

Bony Bridging of the Mylohyoid Groove of the Human Mandible.

“…focused on the influence of environmental factors on bilateral manifestation of these traits under a genetic background. Since the 1960s, it has been demonstrated, on the basis of a good number of morphological studies including those using laboratory animals, that environmental stresses are influential in bilaterality reduction (O'Connell, 1975;Doyle et al, 1977;Siegel et al, 1977;Trinkaus, 1978;Green et al, 1979;Perizonius, 1979;Livshits et al, 1988;Livshits and Kobyliansky, 1991). Therefore, the present findings appear to suggest that the effect of environmental factors is rather small in the formation of mylohyoid bridging.…”

Fluctuating dental asymmetry in rabbits with familial nonsyndromic coronal suture synostosis

“…Importantly, elevated levels of fluctuating asymmetry have been associated with a variety of stressors during development, includ--ing a number of genetic diseases [21]. For example, there is evidence of ele--vated fluctuating asymmetry in hu--mans affected with orofacial clefts [22--25], Down's syndrome [26,27], Fragile--X syndrome [28], premature birth [29,30] attention deficit--hyperactivity disorder [31], general--ized mental retardation [32], spinal malformation [33] and a wide range of psychiatric diseases including schizophrenia, major depression and bipolar disorder [21,34]. Because nonsyndromic craniosynostosis is a disease that disrupts craniofacial de--velopment through abnormal calvari--al bone homeostasis resulting in ex--cessive ossification and premature suture fusion [2,3,35--37], affected organisms likely experience increased systemic stress during ontogeny.…”