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Simian crease

  • Definition
    • A simian crease is a single line that runs across the palm of the hand. People usually have 3 creases in their palms.

      The term "simian crease" is not used much anymore, since it tends to have a negative meaning (the word "simian" refers to a monkey or ape). The crease is usually just referred to as a single palmar crease.

  • Alternative Names
    • Single palmar crease; Transverse palmar crease; Palmar crease

  • Considerations
    • Distinct lines that form creases appear on the palms of the hands and soles of the feet. The palm usually has 3 of these creases. But sometimes, the creases join together to form just one.

      Palmar creases develop while a baby is growing in the womb, usually by the 12th week of gestation.

      A single palmar crease appears in about 1 out of 30 people. Males are twice as likely as females to have this condition. Some single palmar creases may indicate problems with development and be linked with certain disorders.

  • Causes
  • What to Expect at Your Office Visit
    • An infant with a single palmar crease may have other symptoms and signs that, when taken together, define a specific syndrome or condition. Diagnosis of that condition is based on a family history, medical history, and complete physical exam.

      Your health care provider may ask questions such as:

      • Is there a family history of Down syndrome or other disorder associated with a single palmar crease?
      • Does anyone else in the family have a single palmar crease without other symptoms?
      • Did the mother use alcohol while pregnant?
      • What other symptoms are present?

      Based on the answers to these questions, the medical history, and the results of the physical exam, further testing may be necessary.

  • References
    • Marcdante KJ, Kliegman RM. The approach to the dysmorphic child. In: Marcdante KJ, Kliegman RM. Nelson Essentials of Pediatrics. 7th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 50.

      Nussbaum RL, McInnes RR, Willard HF. The chromosomal and genomic basis of disease. In: Thompson & Thompson Genetics in Medicine. 8th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 6.