Mosaicism, lines with various numbers of X chromosomes

This code describes a genetic condition where an individual has two or more cell lines with differing numbers of X chromosomes. This typically involves variations such as 45,X/46,XX or 46,XX/47,XXX, indicating a mixture of cells with monosomy X, normal female karyotype, or polysomy X. The clinical presentation can vary widely depending on the proportion and distribution of the different cell lines.

Assign this code when documentation confirms a mosaic karyotype involving varying numbers of X chromosomes, often identified through cytogenetic analysis. This is appropriate for patients diagnosed with conditions like mosaic Turner syndrome or other X chromosome aneuploidies where multiple cell lines are present. Supporting documentation should include genetic test results detailing the specific mosaicism.

• Ensure the documentation explicitly states "mosaicism" and specifies the involvement of X chromosomes with varying numbers.
• Do not confuse this with non-mosaic X chromosome aneuploidies (e.g., pure Turner syndrome 45,X) which have distinct codes.
• Consider sequencing this code as the primary diagnosis when the mosaicism is the reason for the encounter, followed by any associated clinical manifestations.