Barrier-to-autointegration factor (Breakpoint cluster region protein 1) [Contains: Barrier-to-autointegration factor, N-terminally processed] [BAF] [BCRG1]
Néstor-Guillermo progeria syndrome (NGPS; OMIM 614008) is characterized by early onset and slow progression of symptoms including poor growth, lipoatrophy, pseudosenile facial appearance, and normal cognitive development. In contrast to other progeria syndromes, NGPS is associated with a longer lifespan and higher risk for developing severe skeletal abnormalities. It is an autosomal recessive condition caused by biallelic pathogenic variants in BANF1. There are two previously reported patients with NGPS, both Spanish with molecular diagnoses made in adulthood and having the same homozygous pathogenic variant c.34G > A; p.Ala12Thr. Presented here is a 2 year, 8 month old girl with short stature, poor weight gain, sparse hair, and dysmorphic facial features reminiscent of premature aging. Whole exome sequencing identified the same c.34G > A homozygous pathogenic variant in BANF1 as reported in the previous patients. This is the first reported case of a child and is supporting evidence for this recurrent loss of function variant.
Keywords
Premature aging syndromes recapitulate many aspects of natural aging and provide an insight into this phenomenon at a molecular and cellular level. The progeria syndromes appear to cause rapid aging through disruption of normal nuclear structure. Recently, a coding mutation (c.34G > A [p.A12T]) in the Barrier to Autointegration Factor 1 (BANF1) gene was identified as the genetic basis of Néstor-Guillermo Progeria syndrome (NGPS). This mutation was described to cause instability in the BANF1 protein, causing a disruption of the nuclear envelope structure. Here we demonstrate that the BANF1 A12T protein is indeed correctly folded, stable and that the observed phenotype, is likely due to the disruption of the DNA binding surface of the A12T mutant. We demonstrate, using biochemical assays, that the BANF1 A12T protein is impaired in its ability to bind DNA while its interaction with nuclear envelope proteins is unperturbed. Consistent with this, we demonstrate that ectopic expression of the mutant protein induces the NGPS cellular phenotype, while the protein localizes normally to the nuclear envelope. Our study clarifies the role of the A12T mutation in NGPS patients, which will be of importance for understanding the development of the disease.
MeSH Terms