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What Are the Functions of Chromosome 6p?

Microscopic chromosomes within each of your cells' nuclei determine your genetic makeup. Typically, humans have 23 pairs or 46 individual chromosomes. The Rare Chromosome Disorder Support Group (Unique) explains that each chromosome has a centromere or constriction with a long arm (q) and a short arm (p) that join at the centromere or center. When someone lacks the petite (p) arm of chromosome 6, a rare chromosome condition -- 6p deletion -- occurs either terminally (one break) or interstitially (two breaks). Both breaks affect similar physiological and mental functions, although individual functioning may vary significantly.

  1. Cardiovascular Function

    • Experts associate both the terminal and interstitial forms with compromised heart functions. The United States National Library of Medicine refers specifically to heart murmurs and tachycardia (rapid heart rate). In infants, severe heart conditions can lead to impaired growth and permanent short stature. Hormone treatments, however, may spur normal growth.

    Eyes, Ears and Nose

    • Deletion of this chromosome also affects the anterior (front) section of the eye. With a terminal deletion, the eyes appear slanted, set widely apart. In addition, both deletions may lead to a high probability of hearing impairment, even deafness. Other characteristics include malformation and low positioning of the ears. The nose also has a lower placement and a broader bridge.

    Cognitive Development

    • Both deletions may lead to cognitive delays and moderate or acute learning impairment, including mental retardation. Most assume that the smaller the deletion, the less severe the impairment, but the Rare Chromosome Disorder Support Group (Unique) has noted considerable variability and reports that some children have normal cognitive development. The condition affects language function more than mathematical ability.

    Speech Development

    • Because of problems with hearing and cognitive functions, a delay in communication skills naturally results. At 2-3 years, children with 6p deletion generally begin to speak single words. This developmental delay affects social functioning and self-confidence. Often children learn to mix signing with speech to communicate.

    Motor Functions

    • Although the size of the deletion does not affect mobility, all children with the 6p deletion have delays with motor milestones. At one extreme, infants may experience hypotonia (decreased muscle tone) to varying degrees. Some require a wheelchair for outdoor trips while others enjoy some normal childhood normal activities. (Ref. 1)

    Other Functions

    • Those with interstitial deletions may experience trouble with kidney function, joint dislocation and hernias. Some exhibit other physical features: cleft palate, shortened neck, eczema and malformations of hands or feet. Clearly, not all conditions necessarily manifest themselves in individuals with 6p deletion; individual functioning varies significantly.

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