Trisomy 18, mosaicism (mitotic nondisjunction)
ICD-10 Q91.1 is a billable code used to indicate a diagnosis of trisomy 18, mosaicism (mitotic nondisjunction).
Trisomy 18, also known as Edwards syndrome, is a chromosomal abnormality characterized by the presence of an extra 18th chromosome. Mosaicism refers to a condition where some cells have the extra chromosome while others do not, resulting from mitotic nondisjunction during early cell division. This condition leads to a range of congenital malformations, including severe developmental delays, growth deficiencies, and multiple organ system anomalies. Common physical features include a small head, clenched fists, overlapping fingers, and low-set ears. Infants with Trisomy 18 often present with cardiac defects, renal abnormalities, and gastrointestinal issues. The prognosis for individuals with Trisomy 18 is generally poor, with many affected infants not surviving beyond their first year of life. However, those with mosaic forms may have a better outcome, depending on the proportion of normal cells and the severity of associated anomalies. Accurate diagnosis typically involves karyotyping and genetic counseling to discuss implications for the family.
Detailed growth and developmental assessments, documentation of physical findings, and management plans for associated anomalies.
Infants presenting with developmental delays, congenital heart defects, or feeding difficulties.
Pediatric coders must ensure that all associated congenital anomalies are documented to support the primary diagnosis.
Karyotype results, family history, and genetic counseling notes must be included to support the diagnosis.
Genetic counseling sessions for families with a history of chromosomal abnormalities or prenatal diagnosis of Trisomy 18.
Genetic coders should focus on the implications of mosaicism and the potential for variable clinical outcomes.
Used for confirming the diagnosis of Trisomy 18 through genetic testing.
Karyotype report and clinical indication for testing.
Genetic specialists should ensure that the rationale for testing is clearly documented.
Mosaicism in Trisomy 18 indicates that not all cells have the extra chromosome, which can lead to a milder phenotype and potentially better outcomes compared to non-mosaic forms. Accurate documentation of the mosaic nature is crucial for coding and management.
