Bohring-Opitz syndrome (BOS, OMIM #605039) is characterized by intellectual disorders, characteristic facial features, and multiple anomalies. There is presumably an increased risk of developing Wilms tumors.

Key Data

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Synonyms C-like syndrome, Oberklaid-Danks syndrome
Gene ASXL1 (not all patients have a mutation, which is why it is presumed to be heterogeneic; KLHL7 has been suggested as a recessive gene candidate)
Gene product ASXL1
Function Regulation of HOX genes; chromatin remodeling
Heredity Autosomal dominant (germline mosaicism described in parents)
Prevalence Extremely rare
Genotype-phenotype correlation Unknown
Penetrance Unknown
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The diagnosis is made clinically and confirmed by genetic analysis. The diagnosis of “Bohring-Opitz syndrome” is confirmed with the detection of a heterozygous germline mutation in the ASXL1 gene through sequence analysis or deletion/duplication analysis. The use of panel examinations consisting of multiple genes as well as exome or genome sequencing may also be helpful.

Differential Diagnoses

  • C-syndrome (Opitz trigonocephaly syndrome)

  • Shashi-Pena syndrome (ASXL2 syndrome)

  • Bainbridge-Ropers syndrome (ASXL3 syndrome)

  • Cornelia-de-Lange syndrome (CdLS)

  • KLHL7-associated syndrome

Clinical Presentation

Clinical Presentation

BOS is characterized by severe growth deficits, dietary problems, severe developmental delays and retardation, typical facial features, microcephaly, hirsutism of the forehead, cleft lip palate, retinal changes, flexion anomalies affecting the upper extremities with dislocation of the radial head and ulnar deviation of the fingers, changes affecting the lower extremities, structural brain changes, cramping seizures, and other anomalies. Approximately 40% of patients die during early infancy, usually due to bradycardia, obstructive apnea, or pulmonary infections. In those that survive, the characteristic facial features may subside with time. Girls are affected more frequently than boys. There is presumably an increased risk of developing Wilms tumors.

Therapeutic Considerations

Therapies should be provided by a multidisciplinary team.

Surveillance Recommendations

Surveillance Recommendations

  • It may be worth examining the kidneys by ultrasound every 3 months until the age of 7 to address the presumed increased risk of developing Wilms tumors.