Small inherited terminal duplication of 7q with hydrocephalus, cleft palate, joint contractures, and severe hypotonia

Abstract

We report a 14-month-old girl with submucous cleft palate, resolving mild hydrocephalus, severe hypotonia and joint contractures. The finding of extreme hydrocephalus, cleft palate and club feet in a fetus of the mother's previous pregnancy suggested an inherited defect. Chromosome analysis and FISH studies in the proband revealed an abnormal homolog 13 resulting in a duplication of distal chromosome 7q, 7q35-qter, and a very small associated deletion of distal chromosome 13q, 13q34-qter. The mother showed the balanced translocation. Similar clinical signs have been described with larger distal 7q duplications. Our findings suggest that 7q35-qter, and possibly the gene for sonic hedgehog (SHH) on 7q36, is the critical region for the typical facial features and the profound hypotonia observed in the 'trisomy of distal 7q' syndrome.

De Novo Duplication of Chromosome 7 (q21.1-q32); Case Report and Review of the Literature

“…High resolution chromosomal analysis of the proband showed 46,XY,dup 7(q21.2-q32). Twelve patients with duplication/trisomy of 7q have been reported [1][2][3][4][5][6][7][8]. A summary of clinical findings of patients with partial duplication of 7q is given in Table 1 Our patient confirms that partial trisomy/duplication of 7q is associated with macrocephaly, frontal bossing, failure to thrive, psychomotor delay and malformed ears.…”

“…Partial trisomy/duplication of chromosome 7q is associated with a characteristic syndrome of frontal bossing, retrognathia, small jaw, low-set ears, dysplastic ears, deep-set and prominent eyes, strabismus, down-curved upper lip, small mouth, short hands, stiffness of fingers and other joints, joint laxity, scoliosis, reduced muscle tone, hydrocephalus, growth retardation, strabismus, coloboma of iris, drooping upper eyelid, widely-spaced eyes, long eyelashes and short space between eyelids [1][2][3][4][5][6][7][8].…”

Infantile hydrocephalus: A review of epidemiology, classification and causes

“…In addition to these single-gene disorders, many cytogenetic abnormalities have been linked to hydrocephalus, including microdeletion 9q22.3 [93], partial trisomy 1 [94], deletion 6q26q27 [95, 96], terminal duplication of 7q [97], as well as Trisomy 13, 18, 21 and triploidy [2]. …”

Coexistence of an unbalanced chromosomal rearrangement and spinal muscular atrophy in an infant with multiple congenital anomalies

“…Pure terminal duplication of 7q is a rare occurrence. Most individuals with 7q duplications are reported with concomitant monosomies [Morava et al, 2003;T€ uys€ uz et al, 2008] making a phenotype-genotype correlation challenging. Novales et al [1982] postulated three partial 7q trisomy regions generating three different phenotypes with distal duplications (7q32-7qter) causing frontal bossing, hypertelorism, low set ears, hypotonia, feeding problems, kyphoscoliosis, and developmental delay.…”