LETM1 and Wolf-Hirschhorn syndrome: Although studies in mouse models that have reduced Letm1 expression strongly suggest a link between reduced Letm1 expression and seizures, recent work in individuals with WHS suggests that LETM1 haploinsufficiency might also contribute to growth restriction, feeding difficulties, and motor and speech delays; the mitochondrial dysfunctions revealed here could conceivably contribute to these other characteristic features of WHS.