1q duplications

Symptoms of chromosome 1q duplications generally depend on the size and location of the duplication, and the genes involved. Therefore, symptoms vary. For example, people who have small duplications near the tip of the long (q) arm of chromosome 1 are often mildly affected, while those with larger duplications often have more severe learning difficulties. Children with large duplications that extend to near the center of the chromosome tend to have more severe birth defects and a shortened life expectancy.

Some of the more common features that may occur in people with a chromosome 1q duplications include:

• small and/or receding lower jaw
• high and narrow roof of mouth (palate), and/or cleft palate
• learning difficulties and developmental delay
• heart defects
• slow growth and short stature

Below is a summary of some additional features that have been reported in people with certain types of chromosome 1q duplications, according to a guide provided by Unique. Unique draws information from both the published medical literature and from a survey of members with a chromosome 1q duplication.

Duplications including material near the middle of the chromosome (centromere):

• typically severely affected, sometimes unable to survive infancy independently
• some joints fixed in a rigid, bent position
• hydrocephalus (an excess of fluid around the brain)
• no development of speech
• feeding difficulties

Duplications between bands 1q23-q25 and 1q41:

• small mouth that may not open fully
• low-set, backwards-rotated ears

Large duplications between bands 1q31 and the end of the long arm:

• kidney defects and anomalies of the urinary tract
• minor anomalies of the urinary and genital systems in boys
• eye or vision abnormalities (e.g. strabismus, small eyes, or blindness)
• blockage or narrowing of part of the gastrointestinal tract
• extra fingers or toes, and/or crowded, overriding toes
• low, backwards-rotated ears
• increased risk of respiratory infections

Small duplications from band 1q4:

• large head with a prominent forehead
• initial feeding difficulties and failure to thrive
• highly variable degree of learning difficulty (sometimes no learning difficulty)

To read more about these signs and symptoms and additional symptoms reported in people with chromosome 1q duplication, read Unique's guide entitled 'Duplications of 1q.'