Syndromic Congenital Heart Disease in a Child with 6q24.3-q25.1 Microdeletion: A Case Report with Genotype–Phenotype Correlation

Chromosome 6q24.3-q25.1 microdeletion syndrome is a rare contiguous gene deletion disorder associated with multilevel congenital heart defects, growth abnormalities, and dysmorphic features. We report the case of an 8-month-old female child who presented with fever, cough, and respiratory distress. She had a history of recurrent respiratory symptoms, poor weight gain, feeding difficulties, and developmental delay. Clinical examination revealed syndromic facies, severe undernutrition, and signs of cardiac failure. Echocardiography demonstrated a perimembranous ventricular septal defect, secundum atrial septal defect, subvalvular pulmonary stenosis, bicuspid aortic valve with mild stenosis, and pulmonary arterial hypertension. In view of the multisystem involvement and dysmorphic features, genetic testing was performed. Whole-exome sequencing identified a heterozygous pathogenic deletion at 6q24.3-6q25.1, confirming 6q24-q25 microdeletion syndrome. This case highlights the cardiovascular relevance of recognizing TAB2-associated 6q24.3-q25.1 microdeletion in children with syndromic congenital heart disease, particularly those with multilevel and evolving valvular abnormalities. Identification of the underlying genetic disorder supports etiological diagnosis, longitudinal cardiovascular surveillance, and appropriate multisystem and family counseling.