Monosomy of the long arm of chromosome 7 is characterized by structural abnormalities of the face including a broad nasal bridge with a stubby nose, a large mouth with an everted lower lip and downturned corners, low-set and malformed ears, and skeletal abnormalities such as short hands and feet, clubfeet, and lobster-claw deformities. Hydrocephalus with cortical atrophy and/or seizures may be evident. The specific features of the syndrome are a function of the missing portion of the long arm of chromosome 7.
Individuals with a deletion of the terminal region of chromosome 7 (q3) have the following, relatively consistent features: developmental delay, growth retardation, hypotonia, unusual facial appearance with a broad nasal bridge and bulbous nasal tip, microcephaly, holoprosencephaly, cleft lip and/or palate, anomalous auricles, single transverse palmar creases, genital anomalies in males, abnormal electroencephalogram, and ocular abnormalities. Most terminal deletions extend from the q32 or the q35 bands; the specific breakpoint does not differentiate the two clinically. Generally, affected fetuses or individuals have some ocular abnormality with nonspecific findings such as epicanthus, hypertelorism, and upward slanting of the lids being the most common; synophrys, strabismus, glaucoma, colobomatous microphthalmia, and optic nerve atrophy may occur.35,174'249'335'361,405 Friedrich and colleagues reported an individual with optic atrophy and a coloboma of the optic nerve who had a terminal deletion from the 7q32 region.102 Reynolds and colleagues described a child with a more distal deletion from the 7q34 region who had colobomatous microphthalmia, corneal opacification with vascularization, posteriorly subluxed lenses, and a falciform fold of the retina.283
McMorrow and colleagues reported an infant with bilateral anophthalmia and other malformations associated with an interstitial deletion of the long arm of chromosome 7 from the q21.1 to q36.1 bands.224 Absence of the adrenal glands has been reported in monosomy q1 and q3 (distal deletions).
Life span appears to be longer for monosomy 7q2 as compared to monosomy 7q1 and distal deletions. Ophthalmic manifestations of an interstitial deletion of the q2 band include hypertelorism, epicanthus, and downslanting of the palpebral fissures in monosomy 7q1267; hypertelorism, epicanthus, and short, upslanting palpebral fissures.215,405
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