Neuropediatrics 2013; 44 - PS16_1049
DOI: 10.1055/s-0033-1337817

Nicolaides-Baraitser Syndrome

K Ahlbory 1, C Zweier 2, EC Prott 3, S Endele 2, D Meschede 4, U Kremens-Korsch 1, B Stüve 1, A Bolte 1, A Reis 2, S Waltz 1
  • 1SPZ, Kliniken der Stadt Köln, Köln, Germany
  • 2Humangenetisches Institut, Universitätsklinikum Erlangen, Erlangen, Germany
  • 3Institut für Praenatale Medizin & Humangenetik Wuppertal, Wuppertal, Germany
  • 4Praxis für Humangenetik, Köln, Germany

Case Report: The delineation of the phenotype of Nicolaides-Baraitser syndrome (NBS) and the identification of causative heterozygous missense mutations in the SMARCA2 gene has been made recently.1,2 The gene encodes the core catalytic unit of the SWI/SNF chromatin remodeling complex that is involved in the regulation of gene transcription, DNA repair and cell differentiation. There is a growing number of mutations in genes encoding further subunits of this complex, which can cause developmental abnormalities.

This case report presents a 4.8-year-old boy referred to our epilepsy unit. The distinctive facial morphology patient at the age of 4 years is shown in the image.

The child may be described as follows: sparse scalp hair with low anterior hairline, facial hypertrichosis, triangular face, wide mouth with thin upper and thick lower vermilion, broad philtrum, anteverted nares in combination with a severe mental developmental delay (MFED < 22 month) with autistic features and no language development, microcephaly, as well as pharmacoresistant epilepsy, since the age of 20 month, has led to the diagnosis of NBS which has been confirmed by SMARCA2 gene sequencing (SMARCA2 Exon 18; c.2642G >A; p.Gly881Glu heterozygous). The mutation identified in our patient has not been described so far, but the replacement of the highly conserved amino acid position 881 into valine or arginine is known to be pathogenic.

This case report points to NBS as a rare differential diagnosis in patients with dysmorphism, severe mental developmental delay, and difficult-to-treat epilepsy. The rapidly increasing number of published cases suggests that NBS is more common than anticipated.

References

1. Sousa SB, Abdul-Rahman OA, Bottani A, et al. Nicolaides-Baraitser syndrome: delineation of the phenotype. Am J Med Genet A 2009;149A(8):1628 – 1640

2. Van Houdt JK, Nowakowska BA, Sousa SB, et al. Heterozygous missense mutations in SMARCA2 cause Nicolaides-Baraitser syndrome. Nat Genet 2012;44(4):445 – 449