Identification of novel BCL11A variant in a patient with developmental delay and behavioural differences.

Background: The BCL11A gene is involved in disorders including intellectual disability syndrome (IDS), encodes a zinc finger protein highly expressed in haematopoietic and brain and acts as a transcriptional repressor of foetal haemoglobin (HbF). De novo variants in BCL11A have been associated with IDS, which is characterized by developmental delays, autism spectrum disorder (ASD) and speech and language delays. The reports of BCL11A gene variants are still limited worldwide, and additional cases are needed to expand the variant and phenotype spectrums.

Methods: The patient is a 5-year-old girl who was hospitalized due to developmental delays. After analysing her clinical and pathological characterizations, whole-exome sequencing (WES) was performed for pathogenic genetic variants of developmental delay and behavioural differences. Candidate variant in BCL11A gene was identified and further validated by Sanger sequencing.

Results: A heterozygous variant, c.1442delA (p.Glu481Glyfs*25), was identified in exon 4 of the BCL11A gene through WES. This variant results in a truncated expression of the encoded protein. This de novo variant was confirmed by Sanger sequencing. The language delay and behavioural differences were prominent in our patient.

Conclusion: Our finding demonstrates that BCL11A variant may cause developmental delay and behavioural differences, expanding the genetic spectrum of the BCL11A gene.