4q13-4q21 deletion syndrome: A rare cause of severe growth retardation

Abstract Chromosomal deletion syndromes are a rare group of genetic disorders with variable manifestations depending on deletion size, location, and gene content. We report a 16-month-old boy with severe growth retardation, global developmental delay, and various dysmorphic features and absent dentition. Ophthalmological evaluation showed right disc coloboma and left optic atrophy. He also had profound left-sided hearing loss. The child had recurrent hypoglycemia manifesting within three hours of feeding. On evaluation for hypoglycemia, a critical sample revealed low insulin and C-peptide but normal thyroid and growth hormone function. MRI revealed a hypoplastic pituitary gland. Chromosomal microarray identified a de novo 4.9 Mb deletion of 4q13.2–4q21.2 encompassing genes linked to dentition, growth retardation, intellectual disability and hypoglycemia. This case broadens the phenotypic spectrum of proximal 4q deletion syndrome and underscores the importance of early genetic diagnosis for tailored management and counselling.