Origin of a small metacentric chromosome: Familial and cytogenetic evidence

Taylor, Kenneth M.; Wolfinger, Howard L.; Brown, Michael G.; Chadwick, David L.

doi:10.1111/j.1399-0004.1975.tb01515.x

Cited by 56 publications

(33 citation statements)

References 7 publications

(4 reference statements)

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“…The first case of i(18p) was reported by Froland et al (1963), which was followed by reports on few familial cases (Taylor et al 1975;Takeda et al 1989) and few mosaic cases of i(18p) (Gocke et al 1986;Abeliovich et al 1993;Back et al 1994;Pinto et al 1998). The majority of the i(18p) cases reported so far are sporadic due to de novo formation (Fujita and Fujita 1975;Fryns et al 1990;Singer et al 1990;Back et al 1994;Eggermann et al 1996).…”

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confidence: 99%

De novo isochromosome 18p in a female dysmorphic child

et al. 2006

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Isochromosome 18p results in tetrasomy 18p. Most of the i(18p) cases reported so far in the literature are sporadic due to de novo formation, while familial and mosaic cases are infrequent. It is a rare chromosomal abnormality, occurring once in every 140,000 livebirths, affecting males and females equally. In the present investigation, we report a de novo i(18p) in a female dysmorphic child. The small metacentric marker chromosome was confirmed as i(18p) in the proband by cytogenetic and FISH analysis [47,XX+i(18p)]. Cytogenetic investigations in the family members revealed normal chromosome numbers, indicating the case as a de novo event of i(18p) formation. It could be due to the somewhat advanced maternal age (32 years) and/or expression of recessive genes in the proband, who is the progeny of consanguineous marriage, which could have led to misdivision and nondisjunction of chromosome 18 in meiosis I, followed by failure in the chromatid separation of 18p in meiosis II and by inverted duplication.

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confidence: 99%

De novo isochromosome 18p in a female dysmorphic child

et al. 2006

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“…Takeda et al [44] 18pter->cen No CVD Taylor et al [45] 18pter->cen No CVD displayed a reduced signal at the end of the short arm of the altered chromosome 18 and a normal signal in the regular chromosome 18 (Fig. 2).…”

Section: Resultsmentioning

confidence: 94%

Cardiac malformation of partial trisomy 7p/monosomy 18p and partial trisomy 18p/monosomy 7p in siblings as a result of reciprocal unbalanced malsegregation—and review of the literature

et al. 2012

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We report two unbalanced translocations involving the short arms of chromosomes 7 and 18 due to a balanced translocation 7;18 in the mother. Karyotyping and fluorescence in situ hybridization analysis of the female fetus revealed an unbalanced subtelomeric translocation(karyotype 46,XX,der(18)t(7;18)(p22.3;p11.32)mat resulting in a partial trisomy 7p and a partial monosomy 18p.Array comparative genomic hybridization (CGH) detected a4.44-Mb heterozygous duplication at 7p22.3 to 7p22.1 and a0.178-Mb heterozygous deletion at 18p11.32. Clinical characteristics comprised a mildly stenotic bicuspid aortic valve and a small aortic arch without coarctation. The patient's older brother displayed a reciprocal version of her chromosomal aberration (46,XY,der(7)t(7;18)(p22;p11.32) resulting in a partial monosomy 7p and a partial trisomy 18p. Array CGH revealed a 4.75-Mb heterozygous deletion at 7p22.3p22.1 and a 0.579-Mb duplication at 18p11.32. He presented with tetralogy of Fallot, cleft palate, microcephalus without craniosynostosis, growth retardation, ptosis of the right eyelid, right-sided renal agenesis, unilateral cryptorchism,and mental retardation. In this report, we present the clinical phenotype in patients with aberrations of chromosomes 7p and 18p and reviewed the literature to summarize cardiovascular malformations in these patients.

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“…There have been reports in the literature of ten individuals with non-mosaic duplications of the entire short arm of chromosome 18, Wve of whom were reported to have normal psychomotor development. None were described as having any autistic features (Taylor et al 1975;Takeda et al 1989;WolV et al 1991;Moog et al 1994;Li et al 1998;Rodríguez et al 2007;Mabboux et al 2007;Marical et al 2007). However, minimal if any formal psychometric testing was performed.…”

Section: Discussionmentioning

confidence: 94%

Genetic determinants of autism in individuals with deletions of 18q

et al. 2010

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Previous research has suggested that individuals with constitutional hemizygosity of 18q have a higher risk of autistic-like behaviors. We sought to identify genomic factors located on chromosome 18 as well as other loci that correlate with autistic behaviors. One hundred and five individuals with 18q- were assessed by high-resolution oligo aCGH and by parental ratings of behavior on the Gilliam Autism Rating Scale. Forty-five individuals (43%) had scores within the "possibly" or "very likely" categories of risk for an autism diagnosis. We searched for genetic determinants of autism by (1) identifying additional chromosome copy number changes (2) Identifying common regions of hemizygosity on 18q, and (3) evaluating four regions containing candidate genes located on 18q (MBD1, TCF4, NETO1, FBXO15). Three individuals with a "very likely" probability of autism had a captured 17p telomere in addition to the 18q deletion suggesting a possible synergy between hemizygosity of 18q and trigosity of 17p. In addition, two of the individuals with an 18q deletion and a "very likely" probability of autism rating had a duplication of the entire short arm of chromosome 18. Although no common region of hemizygosity on 18q was identified, analysis of four regions containing candidate genes suggested that individuals were significantly more likely to exhibit autistic-like behaviors if their region of hemizygosity included TCF4, NETO1, and FBXO15 than if they had any other combination of hemizygosity of the candidate genes. Taken together, these findings identify several new potential candidate genes or regions for autistic behaviors.

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Origin of a small metacentric chromosome: Familial and cytogenetic evidence

Cited by 56 publications

References 7 publications

De novo isochromosome 18p in a female dysmorphic child

De novo isochromosome 18p in a female dysmorphic child

Cardiac malformation of partial trisomy 7p/monosomy 18p and partial trisomy 18p/monosomy 7p in siblings as a result of reciprocal unbalanced malsegregation—and review of the literature

Genetic determinants of autism in individuals with deletions of 18q

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