SLC4A10 and Mental deterioration: Previously a de novo balanced translocation disrupting SLC4A10 was identified as a candidate cause of disease in a single individual described to have ‘mental retardation, progressive cognitive decline, and partial complex epilepsy’.26 However, a heterozygous SLC4A10 variant causing a severe monogenic disease is not consistent with the autosomal recessive condition described here, given the unaffected parental/sibling carriers of loss-of-function SLC4A10 variants, and the many heterozygous loss-of-function gene variants listed in gnomAD.