Chromosome 7, Partial Monosomy 7p is a rare chromosomal disorder characterized by deletion (monosomy) of a portion of the short arm (p) of chromosome 7 (7p). Associated symptoms and findings may be variable and may depend on the specific size and location of the deleted segment of 7p. However, in many cases, there is early closure of the fibrous joints (cranial sutures) between certain bones of the skull (craniosynostosis), resulting in an abnormally shaped head. For example, depending on the specific sutures involved, the forehead may appear unusually "triangular shaped" (trigonocephaly) or the head may seem abnormally long and narrow with the top pointed or conical (turricephaly). Affected infants and children may also have additional malformations of the skull and facial (craniofacial) region. Such abnormalities may include an unusually small head (microcephaly), closely or widely set eyes (ocular hypotelorism or hypertelorism), downslanting eyelid folds (palpebral fissures), and/or other findings.
Partial Monosomy 7p may also be characterized by additional physical features, such as growth deficiency, musculoskeletal abnormalities, genital defects, structural malformations of the heart that are present at birth (congenital heart defects), and/or other abnormalities. In addition, some affected individuals may have varying degrees of mental retardation and delays in the acquisition of skills requiring the coordination of mental and motor activities (psychomotor delays). Normal intelligence has also been reported.
In most cases, Chromosome 7, Partial Monosomy 7p appears to result from spontaneous (de novo) errors very early in embryonic development that occur for unknown reasons.