INTRODUCTION: Holoprosencephaly with cyclocephaly is an early disturbance of organogenesis and has been classified as a severe brain malformation starting in 1755 by Eller in Germany, then in 1822 by Etienne Geoffroy de Saint-Hilaire in France, and finally in 1828 by Tiedemann in Germany. In 1839, Dr. Arellano published in Mexico a necropsy case of holoprosencephaly. This was the fourth publication worldwide on this kind of pathological alteration. Furthermore, in reference to diaphragmatic herniation, Arellano's paper is the fourth world report, having appeared 9 years before Bochdalek's publication. We have not found any other report that appeared before 1839 in the Americas on this particular malformation, and we consider that Arellano's paper was the first of its kind on the American continent. CONCLUSION: As is well known, the publications of this Mexican medical researcher were, for his time, at the level of those of the most developed countries. It is also important to know that the medical journal where Arellano's work was published, the "Periódico de la Academia de Medicina de Mégico(sic)," founded and directed by Dr. Manuel Carpio in 1836, is the direct forerunner of the present Gaceta Médica de México, the oldest currently published journal in the Americas.
INTRODUCTION: Holoprosencephaly with cyclocephaly is an early disturbance of organogenesis and has been classified as a severe brain malformation starting in 1755 by Eller in Germany, then in 1822 by Etienne Geoffroy de Saint-Hilaire in France, and finally in 1828 by Tiedemann in Germany. In 1839, Dr. Arellano published in Mexico a necropsy case of holoprosencephaly. This was the fourth publication worldwide on this kind of pathological alteration. Furthermore, in reference to diaphragmatic herniation, Arellano's paper is the fourth world report, having appeared 9 years before Bochdalek's publication. We have not found any other report that appeared before 1839 in the Americas on this particular malformation, and we consider that Arellano's paper was the first of its kind on the American continent. CONCLUSION: As is well known, the publications of this Mexican medical researcher were, for his time, at the level of those of the most developed countries. It is also important to know that the medical journal where Arellano's work was published, the "Periódico de la Academia de Medicina de Mégico(sic)," founded and directed by Dr. Manuel Carpio in 1836, is the direct forerunner of the present Gaceta Médica de México, the oldest currently published journal in the Americas.