Cellular identities in an unusual presentation of cyclopia in a chick embryo

Abstract

Cyclopia is a congenital anomaly characterized by the presence of a single or partially divided eye in a single orbit at the body midline. This condition is usually associated with other severe facial malformations, such as the absence of the nose and, on rare occasions, the presence of a proboscis located above the ocular structures. The developmental origin of cyclopia in vertebrates is the failure of the embryonic prosencephalon to divide properly during the formation of the two bilateral eyes. Although the developmental origin of the cyclopia‐associated proboscis is not clear, it has been suggested that this unique structure results from the disrupted morphogenesis of the olfactory placodes, the main organizers of the developing nose. In this study, we report a spontaneous congenital case of cyclopia with a proboscis‐like appendage in a chick embryo. By means of both conventional histology and immunohistochemical methods, we have analyzed this anomaly in detail to suggest an alternative identity for the anatomical embryonic features of cyclopic vertebrate embryos displaying a proboscis. Our findings are discussed in the context of previously reported cases of cyclopia, and provide additional insight into this complex congenital malformation.

Teratogenic and Neurotoxic Effects of n‐Butanol on Zebrafish Development

“…Eye morphology examinations at 24, 48, 72, and 96 h revealed that n‐butanol applications of 500 mg/L and above caused cyclopia (single eye formation) in the embryos and larvae. In other studies, it has been reported that malformations such as cyclopia are observed in embryos and larvae exposed to alcohol (Arenzana et al 2006; Hallare et al 2006; Santos‐Ledo et al 2011; Palmquist‐Gomes et al 2019). Our research findings are in line with these reports.…”

In Vivo and In Vitro Cartilage Differentiation from Embryonic Epicardial Progenitor Cells

“…Mallory’s trichrome staining of paraffin embedded embryonic and adult samples was performed as previously described [ 49 ]. Some samples were stained with a commercial Alcian blue solution (Sigma, B8438) for 30 min at room temperature, then washed in distilled water and mounted.…”

Síndrome del incisivo central maxilar único.

“…Además se ha visto que todos los casos de ciclopía notificados han tenido un único incisivo central maxilar. (1,4) Es relevante recalcar que dentro de los factores determinantes de la enfermedad se encuentra la presencia de un único incisivo maxilar siendo una de las tres características principales y de mayor prevalencia del Síndrome SMMCI, en segundo lugar se encuentra la presencia de atresia de coanas con una incidencia de 1: 5000 nacidos vivos y por último la holoprosencefalia en 1:16000 nacidos vivos. (5)…”

“…(8) Otro hallazgo clínico característico de suma importancia es la erupción de un diente incisivo simétrico solitario maxilar central justo en línea media del alveolo maxilar alrededor de los 8 meses de vida, siendo así tanto en la dentición primaria como la permanente. (4,8) También se puede observar en el 50% de los casos una baja estatura, un 33% presenta una deficiencia de hormona del crecimiento y microcefalia, hasta un 45% de los casos presenta hipotelorismo y se ha documentado que hasta en un 25% de los casos hay alteraciones cardíacas, principalmente la tetralogía de Fallot. (4) Además, un 90% de los pacientes que presenta el Síndrome SMMCI tiene dificultad respiratoria grave al nacimiento o datos de obstrucción nasal en los primeros días de vida, esto puede ser debido a la atresia de coanas, la estenosis medio nasal o el estrechamiento del orificio nasal anterior al aumentar la resistencia de las vías.…”