#chromosomal anomaly

• From the origin — A Latin phrase meaning 'from the origin' or 'from the very beginning'. In medical genetics and embryology, it is used to describe a chromosomal anomaly, congenital malformation, or metabolic disorder present in the organism's biological framework since the moment of conception (ab origine), as opposed to conditions acquired later in life.
• Aberration / Anomaly — A state, manifestation, or structure presenting a pathological deviation from the normal or physiological type. In genetics, it represents a structural or numerical anomaly of chromosomes; in neuropsychiatry, it denotes a wandering of cognitive functions or a severe thought disorder; in ophthalmology, it indicates an optical error of the eye (refractive defect) preventing a clear image on the retina.
• Aneuploidy — A numerical genetic anomaly consisting of a change in the normal number of chromosomes within a cell or organism, through the loss or gain of one or more chromosomes from the basic diploid set. This structural phenomenon usually occurs as a result of chromosome nondisjunction during meiosis or mitosis and represents a major cause of severe phenotypic developmental disorders and spontaneous abortions.