The article presents a clinical case of a rare hereditary pathology associated with a chromosomal mutation, a deletion of chromosome 18. The presented clinical observation is of professional and scientific interest, as it relates to a rare neurological condition. The rarity of this pathology, its complexity, the presence of complications, the high cost of invasive diagnosis, the phenotype variability, including severe congenital malformations in children with microdeletions, all this leads to underdiagnosis of patients at prenatal screening, followed by complex treatment and medical and psychosocial habilitation of children. In case of psycho-speech delay in infancy, typical of chromosomal microdeletions, genetic counseling and testing are recommended to search for chromosomal disorders. Increasing doctors’ awareness of this condition will contribute to its timely diagnosis and treatment.