Penetrance

To date, penetrance appears to be complete for the pathogenic variants implicated in autosomal recessive SCDO.

Source: GeneReviews — "Spondylocostal Dysostosis, Autosomal Recessive"

Diagnostic Criteria

Suggestive Findings

Spondylocostal dysostosis (SCDO) should be suspected in individuals with the following radiographic features and family history:

• Multiple segmentation defects of the vertebrae (M-SDV) most evident on anteroposterior radiograph of the whole spine. Abnormal segmentation of at least ten contiguous vertebrae. In the affected fetus or young child each vertebra is round or ovoid with smooth boundaries; the appearance of the vertebral column has been referred to as the "pebble beach" sign , especially in DLL3-related SCDO. As ossification proceeds after mid- to late childhood, the "pebble beach" appearance gives way to multiple irregularly shaped vertebral bodies and hemivertebrae that may be difficult to distinguish individually on plain x-ray.

• Mild

scoliosis

Source: GeneReviews — "Spondylocostal Dysostosis, Autosomal Recessive"

Differential Diagnosis

Rarely, spondylocostal dysostosis (SCDO) occurs in association with chromosome abnormalities; however, apart from trisomy 8 mosaicism, no consistent genomic region has been involved, and the significance of these associations is unknown. Autosomal dominant SCDO. One family with autosomal dominant SCDO due to a heterozygous TBX6 pathogenic variant has been reported (OMIM 122600). Additional families with autosomal dominant SCDO without an identified gene have also been reported; in these families the extent of segmentation defects of the vertebrae is quite variable [, , , ]. Spondylothoracic dysostosis (STD), despite similarities to autosomal recessive SCDO, has distinctive phenotypic features that warrant this separate designation.

Source: GeneReviews — "Spondylocostal Dysostosis, Autosomal Recessive"

Management Guidelines

No clinical practice guidelines for autosomal recessive spondylocostal dysostosis (SCDO) have been published. Evaluations Following Initial Diagnosis To establish the extent of disease and needs in an individual diagnosed with autosomal recessive SCDO, the evaluations summarized (if not performed as part of the evaluation that led to the diagnosis) are recommended. Table 3. Autosomal Recessive Spondylocostal Dysostosis: Recommended Evaluations Following Initial Diagnosis

Source: GeneReviews — "Spondylocostal Dysostosis, Autosomal Recessive"

Surveillance Guidelines

To monitor existing manifestations, the individual's response to supportive care, and the emergence of new manifestations, the evaluations summarized in are recommended. Table 5. Autosomal Recessive Spondylocostal Dysostosis: Recommended Surveillance

Source: GeneReviews — "Spondylocostal Dysostosis, Autosomal Recessive"