Terminal deletion of the short arm of chromosome 6 (6P25.3P24.3): a literature review and case report of a Brazilian child

Abstract

Introduction: Deletion syndromes are rare events in clinical practice. A chromosomal deletion occurs when segments of genetic information are missing on a particular chromosome or more. The absence of some genes implies varied phenotypes, which detailed explanation is not fully elucidated yet. Objective: Report the case of a child with a terminal segment deletion of 8,9 Mb on the short arm of chromosome 6 (in 6p25.3p24.3) Methods: This case report was approved by the Ethics and Research Committee of the institution. For its preparation, the exam data provided by the patient's family were added from prenatal to early childhood and the discussion with professionals related to the case. Results: B.A.G., a two-year-old female child, the only daughter of non-consanguineous parents, no family history of similar diseases. She was born by premature cesarean section (GA: 35 weeks), presenting Dandy-Walker malformation, Fallot tetralogy, head circumference in the 97th percentile, and syndromic facies, with hypertelorism, low implantation of the ears, and opacity of both lenses. Conclusion: Deletions on chromosome 6 are a very rare genetic alteration. Until 2004, there were only 43 cases in the medical literature, excluding ring chromosome 6 anomalie31. Regarding the terminal deletions of the short arm, this case specifically - 6p24pter - was associated with developmental delay, brain malformations, abnormalities in the anterior chamber of the eye, hearing loss, and abnormalities in the ear, micrognathia, and heart diseases25.