Ankrd11 is a potential chromatin regulator implicated in neural development and autism spectrum disorder (ASD) with no known function in the brain. Here, we show that knockdown of Ankrd11 in developing murine or human cortical neural precursors caused decreased proliferation, reduced neurogenesis, and aberrant neuronal positioning. Similar cellular phenotypes and aberrant ASD-like behaviors were observed in Yoda mice carrying a point mutation in the Ankrd11 HDAC-binding domain. Consistent with a role for Ankrd11 in histone acetylation, Ankrd11 was associated with chromatin and colocalized with HDAC3, and expression and histone acetylation of Ankrd11 target genes were altered in Yoda neural precursors. Moreover, the Ankrd11 knockdown-mediated decrease in precursor proliferation was rescued by inhibiting histone acetyltransferase activity or expressing HDAC3. Thus, Ankrd11 is a crucial chromatin regulator that controls histone acetylation and gene expression during neural development, thereby providing a likely explanation for its association with cognitive dysfunction and ASD.

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In a large consanguineous Turkish kindred with recessive nonsyndromic, prelingual, profound hearing loss, we identified in the gene FAM65B (MIM611410) a splice site mutation (c.102-1G>A) that perfectly cosegregates with the phenotype in the family. The mutation leads to exon skipping and deletion of 52-amino acid residues of a PX membrane localization domain. FAM65B is known to be involved in myotube formation and in regulation of cell adhesion, polarization, and migration. We show that wild-type Fam65b is expressed during embryonic and postnatal development stages in murine cochlea, and that the protein localizes to the plasma membranes of the stereocilia of inner and outer hair cells of the inner ear. The wild-type protein targets the plasma membrane, whereas the mutant protein accumulates in cytoplasmic inclusion bodies and does not reach the membrane. In zebrafish, knockdown of fam65b leads to significant reduction of numbers of saccular hair cells and neuromasts and to hearing loss. We conclude that FAM65B is a plasma membrane-associated protein of hair cell stereocilia that is essential for hearing.deafness | whole-exome sequencing | congenital | Mendelian disorder | sensorineural H earing loss is the most common sensory problem, affecting approximately 1 in 500 newborns. Most cases are the consequence of mutations in single genes with specific functions in the inner ear (1) (http://hereditaryhearingloss.org). Hearing depends on the ability of the inner ear to convert acoustic waves into electrical signals. This process originates in the stereocilia, actin-rich structures that project from the apical pole of cochlear hair cells and are interconnected in the shape of a staircase to form the hair bundle. Most of the ∼50 hair-bundle proteins identified so far are the products of genes that when mutated lead to hearing loss (2). Thus, the genetic approach has played a major role in elucidating the molecular components of normal hearing.Here we present Family With Sequence Similarity 65, Member B (FAM65B, MIM611410) as a previously unrecognized, plasma membrane-associated protein of hair cell stereocilia. The critical role of FAM65B in human hearing was revealed by genetic analysis of a large family with hereditary deafness. In the zebrafish, knocking down the ortholog of FAM65B led to sensorineural hearing loss. Results A Splice Site Mutation in FAM65B Causes Profound SensorineuralHearing Loss in a Turkish Family. In a large consanguineous kindred of Turkish origin (Fig. 1A), six affected individuals had symmetric profound sensorineural hearing loss (Fig. 1B). Anamnestic evaluation and audiograms indicated congenital/prelingual onset hearing loss in all affected individuals. Available audiograms do not suggest progression of hearing loss. Transient evoked otoacoustic emissions and acoustic reflexes were negative in all affected members of the family. Auditory brainstem responses were absent as well. Affected individuals had neither delay in gross motor development nor balance problems, vertigo, dizziness, or n...