Monosomies and deletions from the autosomes, not elsewhere classified (Q93)
ICD-10 code Q93 covers a group of rare genetic conditions related to the loss or deletion of chromosomes from the autosomes, the numbered chromosomes that carry most genetic information. These codes are used to identify specific chromosomal abnormalities that do not fall into other defined categories.
The section includes codes like Q93.0 for whole chromosome monosomy caused by meiotic nondisjunction, commonly known as complete monosomy 21, and Q93.1 for mosaic monosomy due to mitotic errors. Specific deletions such as Q93.3 for deletions on the short arm of chromosome 4 (Wolf-Hirschhorn syndrome) and Q93.4 for deletions on the short arm of chromosome 5 (Cri du chat syndrome) highlight clinically distinct syndromes. Other notable codes include Q93.51 for Angelman syndrome and Q93.81 for Velo-cardio-facial syndrome (22q11.2 deletion syndrome). The diversity of syndromes listed under Q93 helps medical coders accurately classify a broad range of autosomal chromosomal deletions and monosomies, improving diagnostic clarity and patient care.
Congenital malformations, deformations and chromosomal abnormalities (Q00-Q99)
Chromosomal abnormalities, not elsewhere classified (Q90-Q99)
Q93 Monosomies and deletions from the autosomes, not elsewhere classified
- Q93.0 Whole chromosome monosomy, nonmosaicism (meiotic nondisjunction)
- Q93.1 Whole chromosome monosomy, mosaicism (mitotic nondisjunction)
- Q93.2 Chromosome replaced with ring, dicentric or isochromosome
- Q93.3 Deletion of short arm of chromosome 4
- Q93.4 Deletion of short arm of chromosome 5
Q93.5 Other deletions of part of a chromosome
- Q93.51 Angelman syndrome
- Q93.52 Phelan-McDermid syndrome
- Q93.59 Other deletions of part of a chromosome
- Q93.7 Deletions with other complex rearrangements
Q93.8 Other deletions from the autosomes
- Q93.81 Velo-cardio-facial syndrome
- Q93.82 Williams syndrome
- Q93.88 Other microdeletions
- Q93.89 Other deletions from the autosomes
- Q93.9 Deletion from autosomes, unspecified
Monosomies and deletions from the autosomes, not elsewhere classified (Q93)
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.
Angelman Syndrome
A syndrome characterized by multiple abnormalities, MENTAL RETARDATION, and movement disorders. Present usually are skull and other abnormalities, frequent infantile spasms (SPASMS, INFANTILE); easily provoked and prolonged paroxysms of laughter (hence happy); jerky puppetlike movements (hence puppet); continuous tongue protrusion; motor retardation; ATAXIA; MUSCLE HYPOTONIA; and a peculiar facies. It is associated with maternal deletions of chromosome 15q11-13 and other genetic abnormalities. (From Am J Med Genet 1998 Dec 4;80(4):385-90; Hum Mol Genet 1999 Jan;8(1):129-35)
Osteopoikilosis
An asymptomatic, autosomal dominant trait in which pea-sized sclerotic spots, prominent in the metaphyseal area, are accompanied by unique cutaneous lesions. These are yellowish papules or plaques with increased elastin content. (From Cecil Textbook of Medicine, 19th ed, pp1434-35)
Williams Syndrome
A disorder caused by hemizygous microdeletion of about 28 genes on chromosome 7q11.23, including the ELASTIN gene. Clinical manifestations include SUPRAVALVULAR AORTIC STENOSIS; MENTAL RETARDATION; elfin facies; impaired visuospatial constructive abilities; and transient HYPERCALCEMIA in infancy. The condition affects both sexes, with onset at birth or in early infancy.
