Trisomy 13, mosaicism (mitotic nondisjunction)

This code represents Patau syndrome (Trisomy 13) when it occurs in a mosaic form, meaning only a portion of the body's cells have the extra chromosome 13. This genetic condition is characterized by severe intellectual disability and multiple congenital anomalies, often affecting the heart, brain, and facial structures. The mosaic presentation can lead to a wider spectrum of clinical severity compared to full Trisomy 13.

Use this code when documentation explicitly states a diagnosis of Trisomy 13 with mosaicism, often confirmed by cytogenetic studies showing a mixed cell population. This code is appropriate for patients diagnosed with Patau syndrome where the genetic analysis specifies a mosaic pattern due to mitotic nondisjunction.

• Differentiate from full Trisomy 13 (Q91.3) or partial Trisomy 13 (Q91.4) based on genetic testing results.
• Always review the pathology or genetics report to confirm the specific type of Trisomy 13.
• Code all associated congenital anomalies and manifestations separately, as they are not inherent to the genetic code itself.