Shprintzen-Goldberg Syndrome

Excerpt

Clinical characteristics: Shprintzen-Goldberg syndrome (SGS) is characterized by: delayed motor and cognitive milestones and mild-to-moderate intellectual disability; craniosynostosis of the coronal, sagittal, or lambdoid sutures; distinctive craniofacial features; and musculoskeletal findings including olichostenomelia, arachnodactyly, camptodactyly, pectus excavatum or carinatum, scoliosis, joint hypermobility or contractures, pes planus, foot malposition, and C1-C2 spine malformation. Cardiovascular anomalies may include mitral valve prolapse, secundum atrial septal defect, and aortic root dilatation. Minimal subcutaneous fat, abdominal wall defects, and myopia are also characteristic findings.

Diagnosis/testing: The diagnosis of SGS is established in a proband with a heterozygous pathogenic variant in SKI identified by molecular genetic testing.

Management: Treatment of manifestations: Early intervention for developmental delay with placement in special education programs; standard management of cleft palate and craniosynostosis; surgical fixation may be necessary for cervical spine instability; routine management for scoliosis; surgical correction for pectus excavatum is rarely indicated; physiotherapy for joint contractures; clubfoot deformity may require surgical correction. If aortic dilatation is present, treatment with beta-adrenergic blockers or other medications should be considered in order to reduce hemodynamic stress; surgical intervention for aneurysms may be indicated; treatment of myopia as per ophthalmologist; surgical repair of abdominal hernias as indicated.

Prevention of secondary complications: Subacute bacterial endocarditis prophylaxis is recommended for dental work or other procedures for individuals with cardiac complications.

Surveillance: Developmental assessment with each visit; cervical spine evaluation and clinical evaluation for scoliosis as recommended by orthopedist; imaging per cardiologist familiar with this condition; ophthalmology exams as recommended by ophthalmologist.

Agents/circumstances to avoid: Contact sports; use of agents that stimulate the cardiovascular system; activities that may lead to joint pain and/or injury.

Genetic counseling: SGS, caused by a heterozygous pathogenic variant in SKI, is an autosomal dominant disorder. Most individuals with SGS have unaffected parents, suggesting that the causative variant has occurred either as a de novo event in the affected individual or as a result of germline mosaicism in one of the parents. Affected sibs born to unaffected parents support the occurrence of germline mosaicism in some families with SGS. Once a SKI pathogenic variant has been identified in an affected family member, prenatal testing for a pregnancy at increased risk and preimplantation genetic testing are possible.