Microcephaly (Q02)

Clinical Information for Microcephaly (Q02)

Microcephaly - A congenital abnormality in which the CEREBRUM is underdeveloped, the fontanels close prematurely, and, as a result, the head is small. (Desk Reference for Neuroscience, 2nd ed.)

Nijmegen Breakage Syndrome - A chromosome instability syndrome resulting from a defective response to DNA double-strand breaks. In addition to characteristic FACIES and MICROCEPHALY, patients have a range of findings including RADIOSENSITIVITY, immunodeficiency, increased cancer risk, and growth retardation. Causative mutations occur in the NBS1 gene, located on human chromosome 8q21. NBS1 codes for nibrin, the key regulator protein of the R/M/N (RAD50/MRE11/NBS1) protein complex which senses and mediates cellular response to DNA DAMAGE caused by IONIZING RADIATION.

Athetosis - A dyskinesia characterized by an inability to maintain the fingers, toes, tongue, or other body parts in a stable position, resulting in continuous slow, sinusoidal, and flowing involuntary movements. This condition is frequently accompanied by CHOREA, where it is referred to as choreoathetosis. Athetosis may occur as a manifestation of BASAL GANGLIA DISEASES or DRUG TOXICITY. (From Adams et al., Principles of Neurology, 6th ed, p76)

Hypernatremia - Excessive amount of sodium in the blood. (Dorland, 27th ed)

Cerebrum - Derived from TELENCEPHALON, cerebrum is composed of a right and a left hemisphere. Each contains an outer cerebral cortex and a subcortical basal ganglia. The cerebrum includes all parts within the skull except the MEDULLA OBLONGATA, the PONS, and the CEREBELLUM. Cerebral functions include sensorimotor, emotional, and intellectual activities.

Instructional Notations

Includes Includes
This note appears immediately under a three character code title to further define, or give examples of, the content of the category.

  • hydromicrocephaly
  • micrencephalon

Code First Code First
Certain conditions have both an underlying etiology and multiple body system manifestations due to the underlying etiology. For such conditions, the ICD-10-CM has a coding convention that requires the underlying condition be sequenced first followed by the manifestation. Wherever such a combination exists, there is a "use additional code" note at the etiology code, and a "code first" note at the manifestation code. These instructional notes indicate the proper sequencing order of the codes, etiology followed by manifestation.

  • , if applicable, congenital Zika virus disease

Type 1 Excludes Type 1 Excludes
A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.

  • Meckel-Gruber syndrome Q61.9