Coffin Siris Syndrome (CSS) is a rare neurodevelopmental disorder characterized by intellectual disability, developmental delay, and dysmorphic features. We reported an infant at 3 months of age, attended with unable to meet the milestones. He had thick-arched eyebrows, long eyelashes, bulbous nasal tip, hypertrichosis, thick and everted lips. We studied for different cardiac, genitourinary, gastrointestinal, and ophthalmological abnormalities. Whole exome sequencing of the patient revealed a gene responsible for CSS, a novel de novo frameshift mutation in ARID1B. We identified a novel heterozygote variant c.3955dupC in the ARID1B (p.Gln1319ProfsTer14).
Clinicians should consider the coexistence of genetic syndromes in patients with generalized hypotonia, dysmorphological features, and intellectual disability. Early diagnosis is crucial for alternative therapyies in neurodevelopmental diseases. For this reason, consultations should be requested from genetics departments for more comprehensive genomic testing.