Other sex chromosome abnormalities, male phenotype, not elsewhere classified (Q98)
The ICD-10 code Q98 covers other sex chromosome abnormalities affecting individuals with a male phenotype that are not classified elsewhere. These codes identify specific chromosomal conditions such as various types of Klinefelter syndrome and related disorders.
This section includes codes like Q98.0 for the classic 47,XXY Klinefelter syndrome and Q98.1 for Klinefelter variants with more than two X chromosomes (e.g., XXYY or XXXY). It also captures males with unusual karyotypes, such as 46,XX males under Q98.3, important for cases labeled as sex phenotype-karyotype dissociation syndrome or ovotesticular disorder of sex development. The code Q98.5 identifies 47,XYY syndrome, sometimes called Double Y syndrome. Other codes like Q98.7 and Q98.8 describe sex chromosome mosaicism and other specified abnormalities. These codes help medical coders accurately report conditions linked to sex chromosome differences in males, supporting proper diagnosis and treatment planning.
Congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)
Chromosomal abnormalities, not elsewhere classified (Q90-Q99)
Q98 Other sex chromosome abnormalities, male phenotype, not elsewhere classified
- Q98.0 Klinefelter syndrome karyotype 47, XXY
- Q98.1 Klinefelter syndrome, male with more than two X chromosomes
- Q98.3 Other male with 46, XX karyotype
- Q98.4 Klinefelter syndrome, unspecified
- Q98.5 Karyotype 47, XYY
- Q98.6 Male with structurally abnormal sex chromosome
- Q98.7 Male with sex chromosome mosaicism
- Q98.8 Other specified sex chromosome abnormalities, male phenotype
- Q98.9 Sex chromosome abnormality, male phenotype, unspecified
Other sex chromosome abnormalities, male phenotype, not elsewhere classified (Q98)
Clinical Terms
The following clinical terms provide additional context, helping users better understand the clinical background and common associations for each diagnosis listed in this section. Including related terms alongside ICD-10-CM codes supports coders, billers, and healthcare professionals in improving accuracy, enhancing documentation, and facilitating research or patient education.
Gigantism
The condition of accelerated and excessive GROWTH in children or adolescents who are exposed to excess HUMAN GROWTH HORMONE before the closure of EPIPHYSES. It is usually caused by somatotroph hyperplasia or a GROWTH HORMONE-SECRETING PITUITARY ADENOMA. These patients are of abnormally tall stature, more than 3 standard deviations above normal mean height for age.
Klinefelter Syndrome
A form of male HYPOGONADISM, characterized by the presence of an extra X CHROMOSOME, small TESTES, seminiferous tubule dysgenesis, elevated levels of GONADOTROPINS, low serum TESTOSTERONE, underdeveloped secondary sex characteristics, and male infertility (INFERTILITY, MALE). Patients tend to have long legs and a slim, tall stature. GYNECOMASTIA is present in many of the patients. The classic form has the karyotype 47,XXY. Several karyotype variants include 48,XXYY; 48,XXXY; 49,XXXXY, and mosaic patterns ( 46,XY/47,XXY; 47,XXY/48,XXXY, etc.).
Sotos Syndrome
Congenital or postnatal overgrowth syndrome most often in height and occipitofrontal circumference with variable delayed motor and cognitive development. Other associated features include advanced bone age, seizures, NEONATAL JAUNDICE; HYPOTONIA; and SCOLIOSIS. It is also associated with increased risk of developing neoplasms in adulthood. Mutations in the NSD1 protein and its HAPLOINSUFFICIENCY are associated with the syndrome.
