TABLE 3.

Compilation of individuals investigated with triplet repeat expansion testing, CMA, and karyotype

Testing	Presenting	Variant description	Effect	Diagnosis or note	References
Neurodegenerative disorders
HD/Ataxia panel	Chorea	HTT; pathogenic CAG repeat expansion	Polyglutamine tract expansion	Confirmed HD in four individuals	1
HD/Ataxia panel	Ataxia	ATXN3; pathogenic CAG repeat expansion	Polyglutamine tract expansion	Confirmed SCA3 in four individuals	2,3
Fragile X testing (with no other testing)
Fragile X test	Autism	Normal FMR1 (31 CAG repeats)	–	No further testing	–
Testing for suspected Down syndrome
CMA	Down syndrome	–	Confirmed DS in 11 individuals	DS; CMA was the only test we could obtain at this time	4
Karyotype	Down syndrome	47,XX + 21 and 47,XY + 21	Trisomy 21	Confirmed DS in 12 individuals	–
Karyotype	Unaffected mother	46,XX/47,XX + 21 mosaic	Trisomy 21 mosaic	Explained recurrent DS in family	5
Karyotype	Unaffected mothers	46,XX	Unaffected mothers	Confirmed normal karyotype in three unaffected mothers	–
Karyotype for disorder other than Down syndrome
Karyotype followed by CMA	Dysmorphology, DD, ID	46,XY,der(18)t(5;18) (p13.3;q22.3)	Translocation with deletion/duplication	–	–

References: 1 (Charles et al., 2017), 2 (Yearwood et al., 2018), 3 (Mitchell et al., 2019), 4, (Kruszka et al., 2017), 5 (Sobering et al., 2017).