EXOC6B and spondyloepimetaphyseal dysplasia: Homozygous null mutations in EXOC6B are linked to spondyloepimetaphyseal dysplasia with joint laxity type 3 (SEMD-JL3; OMIM #618395) that manifest largely with skeletal anomalies, such as hyperlaxity of joints and multiple joint dislocation, although some SEMD-JL3 patients do exhibit structural brain abnormalities and cognitive deficits (Girisha et al., 2016; Campos-Xavier et al., 2018; Simsek-Kiper et al., 2022).