BACKGROUND: Mutations in the chromodomain helicase DNA binding protein 7 gene 
(CHD7) lead to CHARGE syndrome, an autosomal dominant multiple malformation 
disorder. Proteins involved in chromatin remodeling typically act in 
multiprotein complexes. We previously demonstrated that a part of human CHD7 
interacts with a part of human CHD8, another chromodomain helicase DNA binding 
protein presumably being involved in the pathogenesis of neurodevelopmental 
(NDD) and autism spectrum disorders (ASD). Because identification of novel CHD7 
and CHD8 interacting partners will provide further insights into the 
pathogenesis of CHARGE syndrome and ASD/NDD, we searched for additional 
associated polypeptides using the method of stable isotope labeling by amino 
acids in cell culture (SILAC) in combination with mass spectrometry.
PRINCIPLE FINDINGS: The hitherto uncharacterized FAM124B (Family with sequence 
similarity 124B) was identified as a potential interaction partner of both CHD7 
and CHD8. We confirmed the result by co-immunoprecipitation studies and showed a 
direct binding to the CHD8 part by direct yeast two hybrid experiments. 
Furthermore, we characterized FAM124B as a mainly nuclear localized protein with 
a widespread expression in embryonic and adult mouse tissues.
CONCLUSION: Our results demonstrate that FAM124B is a potential interacting 
partner of a CHD7 and CHD8 containing complex. From the overlapping expression 
pattern between Chd7 and Fam124B at murine embryonic day E12.5 and the high 
expression of Fam124B in the developing mouse brain, we conclude that Fam124B is 
a novel protein possibly involved in the pathogenesis of CHARGE syndrome and 
neurodevelopmental disorders.