Background Nicolaides-Baraitser syndrome (NCBRS) is a rare genetic condition, with approximately 50 reported cases, characterised by dysmorphic facies, developmental delay, seizures, short stature, sparse hair and prominent interphalangeal joints. Limited cases have followed NCBRS features' evolution. We report a twenty-year follow-up of a NCBRS patient to elucidate the syndrome's natural history.

Case description This patient was born at term to a 28-year-old primigravida mother. His birth weight and head circumference were at the 50th percentile and length was at 10th percentile. Apgars were 9 at 1 and 5 min. He was assessed at 6 weeks for failure to thrive. Initial examination revealed left-sided torticollis, cryptorchidism, hypospadias and umbilical hernia. He had sparse hair, droopy eyelids with curly eyelashes, prominent nasal root, bulbous nose, malar hypoplasia and thin upper vermilion. Karyotype was 46, XY and basic metabolic work-up, brain MRI, abdominal ultrasound, and EEG were normal.

Over years, his mild dysmorphism became more prominent with coarsening of facial features. His lips became fuller with thicker lower vermilion. By age 2, he developed mild scoliosis and seizures. Distal phalangeal broadening was noted at 6-year. Puberty started at age 15–16, with increased self-aggression. Developmentally, there was global mild delays. Short stature and microcephaly persisted into adulthood. Genetic testing confirmed a previously unreported heterozygous mutation in SMARCA2.

Conclusions Our case broadens the NCBRS phenotype, as this mild developmental delay has been rarely described in NCBRS before. It also highlights early recognition challenges since several diagnostic features may only become evident with long-term follow-up, as illustrated in our case.