2q13 Distal Microdeletion: Considering Evidence for an Emerging Syndrome Versus Susceptibility Locus: Twenty-Five New Cases and Review of the Literature

This study investigates distal 2q13 microdeletion, presenting the largest cohort to date, including prenatal cases, alongside a comprehensive literature review. A retrospective analysis was conducted on distal 2q13 microdeletions from clinical charts and laboratory reports. The cohort was divided into "clinically indicated" and "not-clinically indicated" groups based on the reason for chromosomal microarray testing. Clinical cases from medical literature were reviewed and compared with our cohort. The study included 25 cases: 17 index patients and 8 family members, with 47% males and 53% females. Of these, 2 were postnatal and 15 were prenatal. In the "clinically indicated" group, 35% had abnormalities on prenatal ultrasound, while 65% in the "not-clinically indicated" group had no major anomalies. Inheritance was 50% paternal in the "clinically indicated" group, and in the "not-clinically indicated" group, 44% paternal, 22% maternal, and 33% de novo. Symptoms varied from asymptomatic to severe developmental issues. Literature review identified 51 postnatal cases, with intellectual disability, and dysmorphism being common features. Familial cases showed 20% de novo, 20% maternal, 21.5% paternal, and 40% unknown inheritance. Distal 2q13 microdeletion is linked to cognitive impairment risk and should be reported in test results based on parental preferences, requiring special considerations for clinical classification and reporting.