Branchio-Skeleto-Genital Syndrome

At a glance

A genetic disorder resulting in branchial arch, skeletal, and genital anomalies.

Synonyms

BSG Syndrome; Elsahy-Waters Syndrome.

Incidence

Unknown. Only one case report of three boys from a single family.

Genetic inheritance

Presumed autosomal recessive trait. All the affected brothers were offsprings of a first-cousin couple in a family pedigree with a history of consanguinity. Variable expression of the syndrome seems likely as two other siblings had mental retardation, but no other features of the condition.

Pathophysiology

Several laboratory investigations to determine the nature of the chromosomal or metabolic errors failed to delineate a cause. Histologic and radiologic analysis of the dental cysts revealed they were dentigerous (ie, an odontogenic cyst surrounding the crown of an impacted tooth). The teeth from these patients had an unusual form of dentine dysplasia, mainly affecting the bulbar areas, which had not been described previously.

Diagnosis

Clinical course, morphologic appearance, radiology of mandible and maxilla (with multiple dental cysts), and histopathology of the teeth (abnormal dentine dysplasia).

Clinical aspects

The syndrome is characterized by the triad of branchial arch, skeletal, and genital anomalies. Features include moderate to severe mental retardation, seizures, brachycephaly, fusion of the spinous processus between second and third cervical vertebrae, (predominantly) lumbar Schmorl nodes (ie, herniations of the intervertebral disc through the vertebral endplate), pectus excavatum, and penoscrotal hypospadias. Affected children have class III malocclusions with marked, absolute hypoplasia of the maxilla resulting in relative mandibular prognathism, high arched palate with bifid uvula in all and partial cleft of the soft palate in one patient. Multiple maxillary and mandibular dental cysts (with a diameter of up to 3 cm) are present with obvious misalignment of all the teeth in the upper jaw. Eruption of the permanent teeth is disordered, delayed or absent, the dentine is dysplastic and partially obliterates the pulp chambers. The nasal bones are broad and flat, with a wide nasal tip and flared alar cartilages. All patients have hypertelorism, nystagmus on right and left gaze, and divergent strabismus and mild ptosis of the right eye. Incomplete expression of the syndrome may be associated with mental retardation but normal craniofacial morphology. It is noteworthy that some experts questioned the designation “branchial arch syndrome” (because the ears and the lower third of the face are well developed) and suggested the name “craniofacial dysplasia” instead.

Precautions before anesthesia

Obtain a full history of problems associated with the syndrome: mental retardation, seizures (anticonvulsant therapy and its efficacy), and the significance of pectus excavatum (although no patient reportedly suffered from clinically relevant adverse effects from it). Evaluate the airway for potential difficulties (poor dentition, limited neck mobility, ...