The protein product of the CTNS gene is a lysosomal cystin transporter. If defective a lysosomal storage disorder results that is called cystinosis.
| Clinic | Method | Carrier testing |
| Turnaround | 5 days | |
| Specimen type | genomic DNA |
| Clinic | Method | Massive parallel sequencing |
| Turnaround | 25 days | |
| Specimen type | genomic DNA |
| Clinic | Method | Genomic sequencing of the entire coding region |
| Turnaround | 25 days | |
| Specimen type | genomic DNA |
| Clinic | Method | Multiplex Ligation-Dependent Probe Amplification |
| Turnaround | 20 days | |
| Specimen type | genomic DNA |