# SOX9 gene anomalies and campomelic / acampomelic campomelic dysplasia: case report and literature review

## TL;DR

This paper reports a rare case of acampomelic campomelic dysplasia with long-term survival and reviews genetic factors affecting survival rates in related disorders.

## Contribution

The study provides updated survival statistics for acampomelic campomelic dysplasia and CD based on genetic variant types.

## Key findings

- About 90% of acampomelic campomelic dysplasia cases with a genetic diagnosis survive beyond 1 year of age.
- Only 30% of CD cases with a genetic diagnosis survive infancy, with survival rates varying by mutation type.
- Chromosome 17 structural rearrangements in CD are associated with the highest survival rates (80%).

## Abstract

Campomelic dysplasia (CD) is a rare skeletal disorder characterized by the hallmark sign of bent femur or tibial bones or both. Subsequently, patients were identified as having features of CD but lacking the bent limbs. This constellation was later described as acampomelic campomelic dysplasia (ACD). Both CD and ACD are caused by anomalies in the SOX9 gene. Historically, CD has a high mortality rate, and ACD patients are often described similarly. Parents may be counseled to consider pregnancy termination or palliative care. This manuscript describes an index patient with ACD who exhibits prolonged survival, along with an extensive literature review. This review shows that roughly 9 out of 10 cases of acampomelic campomelic dysplasia with a genetic diagnosis survive beyond 1 year of age, most of whom are over 2 years old. In stark contrast, only approximately 3 out of 10 CD cases with a genetic diagnosis survive infancy. However, this CD number is skewed because survival beyond infancy is 2 in 10 or less for splice-site and nonsense pathologic variants, deletions, and insertions; approximately 4 in 10 cases for missense pathologic variants; and approximately 8 in 10 cases for chromosome 17 structural rearrangements. These findings are of critical importance for patient counseling and perinatal care planning.