Clinical Guidance

No genotype-phenotype correlations have been observed. The phenotype reported thus far has been strikingly homogeneous regardless of type of CHST3 pathogenic variant . Persons with homozygous pathogenic missense variants are no less severely affected than those with nonsense variants.

Source: GeneReviews — "Chondrodysplasia with Congenital Joint Dislocations, CHST3-Related"

Diagnostic Criteria

Suggestive Findings

Chondrodysplasia with congenital joint dislocations, CHST3-related (CDCJD-CHST3) should be suspected in individuals with the following clinical radiographic features and family history.

Clinical features

• Joint dislocations at birth (knees, hips, radial heads) with short stature (See .)

• Clubfeet

• Limitation of range of motion that can involve all large joints

• Development of kyphosis and occasionally scoliosis with slight shortening of the trunk in childhood

Radiographic features

Source: GeneReviews — "Chondrodysplasia with Congenital Joint Dislocations, CHST3-Related"

Differential Diagnosis

A summary of key differentiating clinical and radiographic features for chondrodysplasias with multiple dislocations is available in . Selected genes of interest in the differential diagnosis are listed in . Table 2. Genes of Interest in the Differential Diagnosis of Chondrodysplasia with Congenital Joint Dislocations, CHST3-Related

Management Guidelines

No clinical practice guidelines for chondrodysplasia with congenital joint dislocations, CHST3-related (CDCJD-CHST3) have been published. In the absence of published guidelines, the following recommendations are based on the authors' personal experience managing individuals with this disorder. Evaluations Following Initial Diagnosis To establish the extent of disease in an individual diagnosed with CDCJD-CHST3, the evaluations summarized (if not performed as part of the evaluation that led to the diagnosis) are recommended. Table 3. Chondrodysplasia with Congenital Joint Dislocations, CHST3-Related: Recommended Evaluations Following Initial Diagnosis

Source: GeneReviews — "Chondrodysplasia with Congenital Joint Dislocations, CHST3-Related"

Clinical Guidance

Activities with a high impact on joints (e.g., jogging) should be avoided. Obesity, which places an excessive load on the large weight-bearing joints, should be avoided.

Source: GeneReviews — "Chondrodysplasia with Congenital Joint Dislocations, CHST3-Related"

Therapies Under Investigation

Search ClinicalTrials.gov in the US and EU Clinical Trials Register in Europe for information on clinical studies for a wide range of diseases and conditions. Note: There may not be clinical trials for this disorder.

Source: GeneReviews — "Chondrodysplasia with Congenital Joint Dislocations, CHST3-Related"

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.

Chondrodysplasia with Congenital Joint Dislocations, CHST3-Related: Recommended Surveillance

System/Concern | Evaluation | Frequency

Skeletal

| • Clinical joint spine eval w/orthopedist w/experience in skeletal dysplasia

• Radiographs as recommended by orthopedist

| Individualized depending on progression or stability of findings

Cardiac

| Follow-up echocardiogram | Frequency per cardiologist or approximately every 5 yrs

Dental

| Follow-up eval w/dentist | Annually or as needed

Source: GeneReviews — "Chondrodysplasia with Congenital Joint Dislocations, CHST3-Related"