Given the rarity and the phenotypical overlap, Bainbridge-Ropers Syndrome (BRS/BRPS) is associated with Bohring-Opitz Syndrome (BOS/BOPS). Now Alma Kuechler and colleguas report six previously unpublished patients with newly diagnosed heterozygous de novo loss-of-function variants in ASXL3. (Bainbridge–Ropers syndrome caused by loss-offunction variants in ASXL3: a recognizable condition) These new cases, together with the nine patients previously presented by Bainbridge et al. and Dinwiddie et al. (2013), Srivastava et al. and Hori et al.(2016), allow a further characterization and delineation of the clinical phenotype.
Both syndromes (BRS and BOS) share some clinical features like severe muscular hypotonia with frequent drooling, feeding difficulties in infancy, significant motor delay, profound speech impairment and intellectual disability. But while key features of Bohring-Opitz Syndrome as trigonocephaly (only two out 15 patients with BRS) and microcephaly, intrauterine growth retardation, typical BOS-posture and heart shaped birthmark on forehead as well as prominent eyes (with high myopia) are absent in the six cases of Kuechler et al., the patients with BRS do show characteristic craniofacial phenotype so as long face with prominent forehead, arched eyebrows with mild unibrow, downslanting palpebral fissures, prominent nose bridge, small alae nasi, high, narrow palate (which is also a common feature of BOS patients) and relatively little facial expression with open mouth appearance.
The authors come to the conclusion that a further delineation of the clinical phenotype of BRS is needed, but by presenting six newly diagnosed patient they consider “Bainbridge-Ropers Syndrome as distinct entity […] which is distinguishable from Bohring-Opitz Syndrome”.
» Article by Kuechler et al.: Bainbridge–Ropers syndrome caused by loss-offunction variants in ASXL3: a recognizable condition