Kromosomisia

Kromosomisia is the Finnish term for chromosomal disorders, a broad set of genetic conditions caused by abnormalities in chromosomes. These can involve numerical changes (an extra or missing chromosome) or structural changes (deletions, duplications, inversions, or translocations). Abnormalities may occur in sperm or egg or arise during early embryonic development and can be present in all cells or restricted to a mosaic subset. Most cases are de novo, but some are inherited.

Numerical disorders include trisomies such as Down syndrome (trisomy 21), Edwards syndrome (trisomy 18), and Patau syndrome (trisomy 13), as well as sex chromosome conditions such as Turner syndrome (monosomy X) and Klinefelter syndrome (XXY). Structural disorders involve deletions or duplications of chromosome segments and may include conditions like DiGeorge syndrome (22q11.2 deletion) or unbalanced translocations. The clinical impact varies widely depending on the chromosome involved and the size of the affected region.

Detection relies on prenatal screening and diagnostic tests, including ultrasound and maternal serum markers, as well as invasive procedures such as chorionic villus sampling or amniocentesis. Laboratory analyses include karyotyping, fluorescence in situ hybridization (FISH), microarray analysis (CGH or SNP arrays), and, in some cases, sequencing. Postnatal evaluation uses clinical assessment and genetic testing to confirm the diagnosis.

Clinical features range from congenital anomalies and growth delays to neurodevelopmental impairment and fertility issues. Management is multidisciplinary, involving medical care, therapies, educational support, and genetic counseling. Prognosis depends on the specific chromosomal abnormality and associated health issues.