Cervical Ribs Are More Prevalent in Stillborn Fetuses than in Live-Born Infants and Are Strongly Associated with Fetal Aneuploidy

Abstract

This study was undertaken to determine the prevalence of cervical ribs in stillborn fetuses undergoing autopsy at our institution and to search for significant associations with cervical ribs. European studies have reported an increased prevalence of cervical ribs in patients with childhood cancer and in stillborn fetuses. We reviewed data from autopsies performed at Primary Children's Medical Center, Utah, between 2006 and 2009 on 225 stillborns (≥20 weeks) and 93 deceased live-born infants (<1 year). Digital fetal radiographs in anterior-posterior and lateral views had been taken of each subject. Chi-square analysis and general linear models were used for statistical analysis of the data. The overall prevalence of cervical ribs was higher in stillborns than in live-borns who died in the first year (43.1% vs 11.8%). Karyotypes were available for 93 (41.3%) of the stillborns. Of those, cervical ribs were present in 33 of 76 (43.4%) stillborns with normal karyotype and in 13 of 17 (76.4%) stillborns with aneuploidy. Females with unavailable karyotypes were more likely to have cervical ribs than those with normal karyotypes (P = 0.0002). This greater likelihood was not observed in males. Among the stillborns with normal karyotypes, we found no statistically significant association with gender or gestational age at fetal death. There was also no statistically significant association between congenital anomalies and the presence of cervical ribs. Our findings support the hypothesis that cervical ribs are markers for disadvantageous developmental events occurring during blastogenesis and have been subject to strong negative selection during evolution.

Increased prevalence of abnormal vertebral patterning in fetuses and neonates with trisomy 21

“…The prevalence of cervical ribs in cases with trisomy 21 ranged from 12.5 to 57.1% in previously reported studies [14,15,35]. The prevalence of cervical ribs in this study population was only slightly higher (57.4%) and not very different from the study of Castori et al [15], who included the largest study population.…”

“…A high prevalence of vertebral patterning anomalies has also been reported in cases with chromosomal anomalies [8,[11][12][13][14][15]. However, the included study populations were relatively small and in only one of these studies the number of thoracic ribs was compared with a control group [12].…”

Historical perspective on developmental concepts and terminology

“…This selection appears to be indirect and is reflected in the huge variety of deleterious morphological and genetic effects associated with a posterior homeotic transformation of C7 into a T1-like, rib-bearing vertebra. We find more or less well developed cervical ribs in almost one-half of all stillborn fetuses [Furtado et al, 2011]. They have also been seen in childhood cancers [Schumacher et al, 1992]; single umbilical artery may be another such sentinel anomaly.…”

Extraordinary incidence of cervical ribs indicates vulnerable condition in Late Pleistocene mammoths

“…In humans, an incidence higher than 1% has only been found in hospitals or isolated populations (Galis et al 2006). An incidence higher than 25% hase only been found in children with leukemia, brain tumours and neuroblastoma (Schumacher et al 1992;Galis & Metz 2003;Merks et al 2005) and in deceased fetuses and infants (Galis et al 2006;Furtado et al 2011;ten Broek et al 2012). Along with the high incidence of cervical ribs in mammoths, the size of the articulation facets is particularly large (Figs.…”