Beyond chromosome analysis: Additional genetic testing practice in a Down syndrome clinic

Area of Science:

• Medical Genetics
• Genomics
• Clinical Diagnostics

Background:

• Down syndrome (DS) is a genetic disorder often associated with other co-occurring genetic conditions.
• Comprehensive genetic evaluation is crucial for individuals with complex genetic profiles.

Purpose of the Study:

• To investigate the utility and outcomes of genetic testing beyond standard chromosome analysis in individuals with Down syndrome.
• To determine the frequency and types of secondary genetic diagnoses identified in this population.

Main Methods:

• Retrospective chart review of 637 individuals with Down syndrome at a DS specialty clinic.
• Analysis of genetic tests performed beyond chromosome analysis, including chromosomal microarray, gene panels, and whole exome sequencing.
• Review of indications for testing and documented results.

Main Results:

• 146 genetic tests were performed on 92 individuals with DS.
• Testing was indicated for conditions such as autism spectrum disorder, celiac disease, dementia, and hematologic diseases.
• Eleven individuals (approximately 12% of those tested) received a second genetic diagnosis.

Conclusions:

• Genetic testing beyond routine chromosome analysis in individuals with Down syndrome can identify additional genetic diagnoses.
• Consideration of further genetic testing is warranted for DS patients exhibiting features suggestive of secondary genetic conditions.
• Multidisciplinary clinics play a vital role in facilitating comprehensive genetic evaluations for Down syndrome patients.