SOX2 Disorder

Clinical characteristics: The phenotypic spectrum of SOX2 disorder includes anophthalmia and/or microphthalmia, brain malformations, developmental delay / intellectual disability, esophageal atresia, hypogonadotropic hypogonadism (manifest as cryptorchidism and micropenis in males, gonadal dysgenesis infrequently in females, and delayed puberty in both sexes), pituitary hypoplasia, postnatal growth delay, hypotonia, seizures, and spastic or dystonic movements.

Diagnosis/testing: The diagnosis of SOX2 disorder is established in a proband in whom molecular genetic testing identifies either a heterozygous intragenic SOX2 pathogenic (or likely pathogenic) variant or a deletion of 3q26.33 involving SOX2.

Management: Treatment of manifestations: Treatment usually involves a multidisciplinary team including – as needed – an experienced pediatric ophthalmologist, ophthalmo-plastic surgeon (for children with anophthalmia and/or extreme microphthalmia), and early educational intervention through community vision services and/or school district; educational support for school-age children; pediatric endocrinologist; pediatric neurologist; and physical therapist and occupational therapist.

Surveillance: Routine follow up with specialists managing the vision, educational, endocrine, and neurologic manifestations.

Genetic counseling: SOX2 disorder, caused by an intragenic SOX2 pathogenic variant or a deletion of 3q26.33 involving SOX2, is an autosomal dominant disorder. Approximately 60% of affected individuals have a de novo genetic alteration. Some affected individuals have inherited the genetic alteration from either an affected mother (transmission from an affected father to child has not been reported to date) or an unaffected parent with germline mosaicism. Once the causative genetic alteration has been identified in an affected family member (or in a parent who has a structural chromosome rearrangement involving the 3q26.33 region), prenatal testing for a pregnancy at increased risk is possible, and preimplantation genetic testing for SOX2 disorder may be possible, depending on the specific familial genetic alteration.