Duplication 17q2

Duplication of the short arm of chromosome 17 in band 2 causes holoprosencephaly, polymicrogyria, a broad forehead and midface with a widow's peak, cleft palate, and a short neck. Additional features include skeletal anomalies such as scoliosis, shortening of the proximal limbs, brachy-, syn-, or polydactyly, and cardiac and genitourinary malformations. Ophthalmic features include hypertelorism and narrow palpebral fissures.140,197,237

Duplication 18p and q11

Duplication of the short arm of chromosome 1S with or without duplication of band 11 of the long arm causes prenatal growth retardation; craniofacial characteristics include microcephaly, a thin nose with a depressed bridge, narrow palate, malformed ears, micrognathia, and a short neck with redundant skin folds. Additional features include narrow shoulders, short sternum, widely spaced nipples, joint contractures, and digital anomalies; cardiac malformations may occur. Ophthalmic features include hypotelorism, downward slanting of the palpebral fissures, and strabismus.101,150,354

Duplication 18q

Duplication of the long arm of chromosome 18 causes distinctive craniofacial features including a broad, high forehead; prominent nasal bridge with absent frontonasal angle; bulbous nasal tip; and a large mouth with full lips. Epicanthus, ble-pharoptosis, synophrys, and enophthalmia occur in duplication of band 1.108,119 Epicanthus, hypertelorism, and upward slanting of the palpebral fissures may be evident in duplication of band

2.73,356

Duplication 19q (de Grouchy Syndrome)

Duplication of the long arm of chromosome 19 causes severe pre- and postnatal growth retardation with microbrachycephaly and seizures; craniofacial features include open fontanelles, a flat facies, small nose with a flat bridge, low-set ears, short and prominent philtrum, downturned corners of the mouth, and short neck. Additional features include deformities of the chest, hands, and feet; cardiac, renal, bronchial, and vertebral anomalies; and genital malformations in males. Ophthalmic features include hypertelorism, downward slanting of the palpebral fissures, and blepharoptosis.1912S7

Duplication 20p

Duplication of the short arm of chromosome 20 causes growth retardation with distinctive craniofacial features including wide cranial sutures, a round face with prominent cheeks, short nose with a broad upturned tip and large nares, long philtrum, large ears, and small chin. Additional features include skeletal, cardiac, and renal anomalies, hypogonadism, and macroorchidism. Ophthalmic manifestations include epican-thus, hypertelorism, up- or downward slanting of the palpebral fissures, strabismus, anterior segment abnormalities of the Rieger syndrome, colobomata, and enophthalmia.18,31,100

Duplication 22q

The "cat-eye" syndrome is a combination of two features, coloboma of the uveal tract (iris and/or choroid) and imperforate anus or anal atresia with retrovesical or rectovaginal fistula. The facies are unusual, with preauricular fistulas with skin tags, and a small chin may be evident. Most children have psychomotor retardation. Each of the three patients initially described had an extra acrocentric chromosome, smaller than either chromosome 21 or 22.305 In those families in which more than one member has the extra chromosome, there has not been a correlation of the full syndrome with the presence of the extra chromosome. The origin of the extra chromosome was identified using DNA probes and is from within the long arm of chromosome 22 (q11 band); there are three or four copies of this region in affected individuals.80,81,221 Ophthalmic features include hypertelorism, epicanthus, downward slanting of the palpebral fissures, strabismus, and colobomatous microphthalmia which is a consistent feature.152,160,164

Duplication of bands 12 and 13 of the long arm of chromosome 22 causes growth retardation with microcephaly and/or hydrocephalus, central nervous system malformations, short and broad nose, cleft lip and/or palate, and short neck; additional features include cardiac and genitourinary malformations and clubfoot. Ophthalmic features include hypertelorism, narrow palpebral fissures, corneal opacities, sclerocornea, and microph-thalmia with orbital cyst.3,288

OTHER ANEUPLOIDY SYNDROMES Triploidy

Triploidy causes multiple congenital anomalies and severe intrauterine growth retardation; the condition is lethal. Affected fetuses and infants have central nervous system malformations including hydrocephalus and hypoplasia of the cortex and/or cerebellum and anomalies of internal organs including the gen itourinary, cardiac, intestinal, and endocrine systems. Hydatid-iform mole may develop. Ophthalmic features include hypertelorism, cataracts, glaucoma, and colobomatous microphthalmia.26'137'324'366

Tetraploidy

The physical features of tetraploidy are similar to triploidy. Death occurs by or within the perinatal period. Reported ophthalmic features include hypertelorism, hypoplasia/aplasia of the optic tract, and microphthalmia.137,304,391

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