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  2. ICD-10-CM Codes List
  3. E00–E89
  4. E70-E88
  5. Disorders of aromatic amino-acid metabolism (E70)

Disorders of aromatic amino-acid metabolism (E70)

The ICD-10 code section E70 covers disorders of aromatic amino-acid metabolism, which includes specific metabolic conditions related to amino acids like phenylalanine, tyrosine, histidine, and tryptophan. These codes identify disorders such as phenylketonuria, tyrosinemia, various forms of albinism, and other enzyme deficiencies associated with amino acid processing.

This section helps medical coders correctly classify conditions ranging from E70.0 for classical phenylketonuria (often simply called phenylketonuria) to E70.21 for tyrosinemia, a disorder affecting tyrosine metabolism. Albinism-related codes like E70.3 capture different types including ocular and oculocutaneous albinism, with detailed subcodes such as E70.310 for X-linked ocular albinism. Disorders of histidine and tryptophan metabolism are noted under codes like E70.4 and E70.5, with histidinemia and tryptophanuria as examples. This ICD-10 code section ensures precise identification of these rare enzyme-related metabolic and pigmentary disorders, aiding in targeted diagnosis and treatment decisions.

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.

Albinism

General term for a number of inherited defects of amino acid metabolism in which there is a deficiency or absence of pigment in the eyes, skin, or hair.

Albinism, Ocular

Albinism affecting the eye in which pigment of the hair and skin is normal or only slightly diluted. The classic type is X-linked (Nettleship-Falls), but an autosomal recessive form also exists. Ocular abnormalities may include reduced pigmentation of the iris, nystagmus, photophobia, strabismus, and decreased visual acuity.

Albinism, Oculocutaneous

Heterogeneous group of autosomal recessive disorders comprising at least four recognized types, all having in common varying degrees of hypopigmentation of the skin, hair, and eyes. The two most common are the tyrosinase-positive and tyrosinase-negative types.

Piebaldism

Autosomal dominant, congenital disorder characterized by localized hypomelanosis of the skin and hair. The most familiar feature is a white forelock presenting in 80 to 90 percent of the patients. The underlying defect is possibly related to the differentiation and migration of melanoblasts, as well as to defective development of the neural crest (neurocristopathy). Piebaldism may be closely related to WAARDENBURG SYNDROME.

Waardenburg Syndrome

Rare, autosomal dominant disease with variable penetrance and several known clinical types. Characteristics may include depigmentation of the hair and skin, congenital deafness, heterochromia iridis, medial eyebrow hyperplasia, hypertrophy of the nasal root, and especially dystopia canthorum. The underlying cause may be defective development of the neural crest (neurocristopathy). Waardenburg's syndrome may be closely related to piebaldism. Klein-Waardenburg Syndrome refers to a disorder that also includes upper limb abnormalities.