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Sheth F, Liehr T, Shah V, Shah H, Tewari S, Solanki D, Trivedi S, Sheth J. A child with intellectual disability and dysmorphism due to complex ring chromosome 6: identification of molecular mechanism with review of literature. Ital J Pediatr 2018; 44:114. [PMID: 30305128 PMCID: PMC6180451 DOI: 10.1186/s13052-018-0571-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2018] [Accepted: 09/21/2018] [Indexed: 11/29/2022] Open
Abstract
Background Ring chromosome 6 (r(6)) is a rare disorder that mainly occurs as a ‘de novo’ event. Nonetheless, a wide phenotypic spectrum has been reported in r(6) cases, depending on breakpoints, size of involved region, copy number alterations and mosaicism of cells with r(6) and/or monosomy 6 due to loss of r(6). Case presentation An 11-year-old male was referred with developmental delay, intellectual disability and microcephaly. Physical examination revealed additionally short stature and multiple facial dysmorphisms. Banding cytogenetic studies revealed a karyotype of mos 46,XY,r(6)(p25.3q27)[54]/45,XY,-6[13]/46,XY,r(6)(::p25.3→q27::p25.3→q27::)[13]/46,XY[6]/47,XY,r(6)(p25.3q27)×2[2]dn. Additionally, molecular karyotyping and molecular cytogenetics confirmed the breakpoints and characterized a 1.3 Mb contiguous duplication at 6p25.3. Conclusion The present study has accurately identified copy number alterations caused by ring chromosome formation. A review of the literature suggests that hemizygous expression of TBP gene in 6q27~qter, is likely to be the underlying cause of the phenotype. The phenotypic correlation and clinical severity in r(6) cases continue to remain widely diverse in spite of numerous reports of genomic variations.
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Affiliation(s)
- Frenny Sheth
- FRIGE's Institute of Human Genetics, FRIGE House, Jodhpur Gam Road, Satellite, Ahmedabad, 380009, India.
| | - Thomas Liehr
- University Clinic Jena, Institute of Human Genetics, Am Klinikum 1, 07747, Jena, Germany
| | - Viraj Shah
- FRIGE's Institute of Human Genetics, FRIGE House, Jodhpur Gam Road, Satellite, Ahmedabad, 380009, India
| | - Hillary Shah
- FRIGE's Institute of Human Genetics, FRIGE House, Jodhpur Gam Road, Satellite, Ahmedabad, 380009, India
| | - Stuti Tewari
- FRIGE's Institute of Human Genetics, FRIGE House, Jodhpur Gam Road, Satellite, Ahmedabad, 380009, India
| | - Dhaval Solanki
- Mantra Child Neurology & Epilepsy Hospital, 3rd floor, Oarnate complex, Kalubha road, Kalanala, Bhavanagar, 364001, India
| | - Sunil Trivedi
- FRIGE's Institute of Human Genetics, FRIGE House, Jodhpur Gam Road, Satellite, Ahmedabad, 380009, India
| | - Jayesh Sheth
- FRIGE's Institute of Human Genetics, FRIGE House, Jodhpur Gam Road, Satellite, Ahmedabad, 380009, India
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2
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Liu S, Wang Z, Wei S, Liang J, Chen N, OuYang H, Zeng W, Chen L, Xie X, Jiang J. Gray Matter Heterotopia, Mental Retardation, Developmental Delay, Microcephaly, and Facial Dysmorphisms in a Boy with Ring Chromosome 6: A 10-Year Follow-Up and Literature Review. Cytogenet Genome Res 2018; 154:201-208. [DOI: 10.1159/000488692] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Indexed: 11/19/2022] Open
Abstract
Ring chromosome 6, r(6), is an extremely rare cytogenetic abnormality with clinical heterogeneity which arises typically de novo. The phenotypes of r(6) can be highly variable, ranging from almost normal to severe malformations and neurological defects. Up to now, only 33 cases have been reported in the literature. In this 10-year follow-up study, we report a case presenting distinctive facial features, severe developmental delay, and gray matter heterotopia with r(6) and terminal deletions of 6p25.3 (115426-384174, 268 kb) and 6q26-27 (168697778-170732033, 2.03 Mb) encompassing 2 and 15 candidate genes, respectively, which were detected using G-banding karyotyping, FISH, and chromosomal microarray analysis. We also analyzed the available information on the clinical features of the reported r(6) cases in order to provide more valuable information on genotype-phenotype correlations. To the best of our knowledge, this is the first report of gray matter heterotopia manifested in a patient with r(6) in China, and the deletions of 6p and 6q in our case are the smallest with the precise size of euchromatic material loss currently known.
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3
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Lee SJ, Han DK, Cho HJ, Cho YK, Ma JS. Mosaic ring chromosome 6 in an infant with significant patent ductus arteriosus and multiple congenital anomalies. J Korean Med Sci 2012; 27:948-52. [PMID: 22876064 PMCID: PMC3410245 DOI: 10.3346/jkms.2012.27.8.948] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Accepted: 04/19/2012] [Indexed: 11/21/2022] Open
Abstract
The clinical features of ring chromosome 6 include central nervous system anomalies, growth retardation, facial dysmorphism and other congenital anomalies. Ring chromosome 6 occurs rarely and manifests as various phenotypes. We report the case of mosaic ring chromosome 6 by conventional karyotyping in a 7-day-old male infant diagnosed with a large patent ductus arteriosus (PDA) with hypoplasia of aortic valve and aortic arch. These have not been previously reported with ring chromosome 6. He recovered from heart failure symptoms after ligation of the PDA. He showed infantile failure to thrive and delayed milestone in a follow-up evaluation. To the best of our knowledge, this is the first report of a Korean individual with ring chromosome 6 and hemodynamically significant PDA.
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MESH Headings
- Abnormalities, Multiple/diagnosis
- Abnormalities, Multiple/diagnostic imaging
- Abnormalities, Multiple/genetics
- Aorta, Thoracic/diagnostic imaging
- Aortic Valve/diagnostic imaging
- Chromosome Disorders/diagnosis
- Chromosome Disorders/genetics
- Chromosomes, Human, Pair 6/genetics
- Ductus Arteriosus, Patent/diagnosis
- Ductus Arteriosus, Patent/diagnostic imaging
- Ductus Arteriosus, Patent/genetics
- Humans
- Infant
- Karyotyping
- Male
- Ring Chromosomes
- Tomography, X-Ray Computed
- Ultrasonography
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Affiliation(s)
- Seung Jae Lee
- Department of Pediatrics, Chonnam National University Medical School, Chonnam National University Hospital, Gwangju, Korea
| | - Dong Kyun Han
- Department of Pediatrics, Chonnam National University Medical School, Chonnam National University Hospital, Gwangju, Korea
| | - Hwa Jin Cho
- Department of Pediatrics, Chonnam National University Medical School, Chonnam National University Hospital, Gwangju, Korea
| | - Young Kuk Cho
- Department of Pediatrics, Chonnam National University Medical School, Chonnam National University Hospital, Gwangju, Korea
| | - Jae Sook Ma
- Department of Pediatrics, Chonnam National University Medical School, Chonnam National University Hospital, Gwangju, Korea
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4
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Höckner M, Utermann B, Erdel M, Fauth C, Utermann G, Kotzot D. Molecular characterization of a de novo ring chromosome 6 in a growth retarded but otherwise healthy woman. Am J Med Genet A 2008; 146A:925-9. [PMID: 18302251 DOI: 10.1002/ajmg.a.32251] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The phenotype of patients with a ring chromosome 6 can be highly variable ranging from almost normal to severe malformations and mental retardation. Size and structure of the ring chromosome as well as the level of mosaicism are important factors for the clinical phenotype. Here, we report on a 25-year-old woman with short stature, minor scoliosis, normal fertility, appropriate psychomotor development, minor dysmorphisms, and a de novo ring chromosome 6. Conventional karyotyping as well as molecular cytogenetic and molecular investigations of DUSP22 on 6p and RP1-191N21.4 on 6q by a new technical approach indicated breakpoints less than 240 kb and less than 190 kb proximal to the telomeres of 6p and 6q, respectively. In addition, formation of the ring chromosome from the paternal chromosome was demonstrated. Thus this case clearly shows that in patients with ring chromosomes without loss of euchromatic material mitotic instability of the ring chromosome is the most important reason for growth retardation and minor congenital anomalies.
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Affiliation(s)
- Martina Höckner
- Division of Clinical Genetics, Department of Medical Genetics, Molecular and Clinical Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
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5
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Andrieux J, Devisme L, Valat AS, Robert Y, Frnka C, Savary JB. Prenatal diagnosis of ring chromosome 6 in a fetus with cerebellar hypoplasia and partial agenesis of corpus callosum: case report and review of the literature. Eur J Med Genet 2005; 48:199-206. [PMID: 16053913 DOI: 10.1016/j.ejmg.2005.01.028] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2004] [Indexed: 11/28/2022]
Abstract
Ring chromosome 6 (RC6) is a rare constitutional abnormality, with variable material loss, leading to a variable clinical phenotype: minimal physical anomalies and mild psychomotor retardation to severe physical and mental defects. Among the 22 published cases, only five have been prenatally detected. We describe here a RC6 prenatally diagnosed. Ultrasound follow-up showed growth retardation and cerebellar hypoplasia. Magnetic resonance imaging (MRI) confirmed this, but showed a partial corpus callosum agenesis, leading to amniocentesis and revealing the chromosomal abnormality. Imaging features were correlated with autopsy findings.
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Affiliation(s)
- Joris Andrieux
- Laboratoire de Génétique Médicale-Barre Nord-Hôpital Jeanne de Flandre, CHRU Lille, 59037 Lille cedex, France.
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6
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Zhang HZ, Li P, Wang D, Huff S, Nimmakayalu M, Qumsiyeh M, Pober BR. FOXC1 gene deletion is associated with eye anomalies in ring chromosome 6. Am J Med Genet A 2004; 124A:280-7. [PMID: 14708101 DOI: 10.1002/ajmg.a.20413] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We report a case of ring chromosome 6 presenting with growth and mental retardation, cerebral dysgenesis, eye malformations, mixed hearing loss, and abnormal physical features. Fluorescent in situ hybridization (FISH) and microsatellite genotyping demonstrated segmental deletions of less than 6 Mb on 6p and 1-2 Mb on 6q. The primary karyotype is designated as 46,XY,r(6)(p25q27).ish r(6)(p25.1q27)(D6S344-, FOXC1-, D6S1574+, D6S281-, D6S297+). Secondary structural and numerical variants of the ring 6 were observed in 16% of the cells analyzed. Intragenic genotyping revealed deletion of the paternal FOXC1 gene, haploinsufficiency of which has been reported to cause eye anterior chamber developmental defects. Accordingly, we propose that our patient's ophthalmologic abnormalities result from haploinsufficiency of the transcription factor FOXC1. We present clinical and cytogenetic summaries on 23 reported cases of ring 6 and categorize them into mild, moderate, and severely affected groups. Further phenotype comparisons between cases with ring 6 and cases with only 6p or 6q terminal deletions suggest that genes important for hearing, vision, and central nervous system development remain to be identified in chromosome 6 terminal regions. Molecular definition of the fusion points and tissue mosaicism studies are necessary to better understand the genotype-phenotype correlation of ring 6. We recommend ophthalmology, audiology, cardiology, and central nervous system examinations be part of the routine evaluation for children with a ring chromosome 6.
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Affiliation(s)
- Hui Z Zhang
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut 06520, USA
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7
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Urban M, Bommer C, Tennstedt C, Lehmann K, Thiel G, Wegner RD, Bollmann R, Becker R, Schulzke I, Körner H. Ring chromosome 6 in three fetuses: case reports, literature review, and implications for prenatal diagnosis. AMERICAN JOURNAL OF MEDICAL GENETICS 2002; 108:97-104. [PMID: 11857558 DOI: 10.1002/ajmg.10215] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Prenatal and postnatal findings in three fetuses with a ring chromosome 6 are presented, and the literature of this rare cytogenetic disorder is reviewed. The described fetuses illustrate the broad spectrum of the clinical manifestation of ring chromosome 6. In one fetus, the disorder was diagnosed incidentally by a routine amniocentesis due to advanced maternal age. The other two fetuses were hydrocephalic and had other congenital anomalies. Remarkably, the ring chromosome 6 tends to disappear in cultured amniotic fluid cells; karyotyping revealed complete or nearly complete monosomy 6. In contrast, the ring was preserved in high proportions of fetal leukocytes. Postnatal growth retardation is the only consistent finding of this chromosomal disorder. Maternal age is not significantly above average. An additional review of 20 literature cases revealed a striking tendency to hydrocephalus, either due to deficient brain growth or secondary to an aqueductal stenosis. Children with hydrocephalus and ring chromosme 6 tend to display facial dysmorphism and may have additional malformations, growth failure, eye anomalies, and seizures. In contrast, there are two reports on children with a ring chromosome 6 who had short stature, normal appearance, and a normal or almost-normal psychomotor development. In such patients at the mild end of the clinical spectrum, the phenotype is basically restricted to what Kosztolányi. [1987: Hum Genet 75:174-179] delineated as "ring syndrome," comprising "severe growth failure without major malformations, without a specific deletion syndrome, with only a few or no minor anomalies, and mild to moderate mental retardation." This "ring syndrome" is considered to occur independently of the autosome involved in the ring formation. The overall impression from our cases and from the literature review of cases with ring chromosome 6 is that the karyotype-genotype correlation is poor. This makes prognostic counseling of parents difficult and unsatisfactory. Serial targeted ultrasound examinations, especially of the brain, are decisive factors in elucidating the prognosis.
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Affiliation(s)
- Maik Urban
- Institut für Medizinische Genetik, Universitätsklinikum Charité, Humboldt-Universität zu, Berlin, Germany
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8
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Ivanovich JL, Watson MS, Whelan AJ. An 11-year-old boy with mosaic ring chromosome 6 and dilated aortic root. AMERICAN JOURNAL OF MEDICAL GENETICS 2001; 98:182-4. [PMID: 11223855 DOI: 10.1002/1096-8628(20010115)98:2<182::aid-ajmg1028>3.0.co;2-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Autosomal ring chromosomes are rare abnormalities that are inherently unstable. Children with ring chromosome 6 have a wide range of intellectual functioning and congenital anomalies. Cardiac lesions are rarely reported with this chromosome abnormality. We report on a 11-year-old boy with mosaic ring chromosome 6 and a dilated aortic root.
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Affiliation(s)
- J L Ivanovich
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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9
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Birnbacher R, Chudoba I, Pirc-Danoewinata H, König M, Kohlhauser C, Schnedl W, Haas OA. Microdissection and reverse painting reveals a microdeletion 6(q26qter) in a de novo r(6) chromosome. ANNALES DE GENETIQUE 2001; 44:13-8. [PMID: 11334612 DOI: 10.1016/s0003-3995(00)01033-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Ring chromosomes 6 are rare constitutional abnormalities with inconsistent phenotypic and clinical features. One of the reasons for this variability is the cytogenetically undetectable loss of chromosomal material from the telomeric segments at 6p or 6q. We have therefore used fluorescence in situ hybridization (FISH) to analyse a ring chromosome 6 that was detected in a newborn boy with dysmorphic features. Reverse painting of the microdissected ring chromosome onto normal metaphase spreads revealed a small deletion of the terminal region of the long arm, 6(q26qter). Moreover, the simple all-telomeric sequence (TTAGG)n was lost, whereas the p-specific subtelomeric sequence was still present. Our findings confirm that microdeletions occur during the formation of r(6) chromosomes and, therefore, are an important determinator of the associated phenotype.
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Affiliation(s)
- R Birnbacher
- Pediatric Clinic, Medical School, University, Vienna, Austria
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10
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Rubtsov N, Senger G, Kuzcera H, Neumann A, Kelbova C, Junker K, Beensen V, Claussen U. Interstitial deletion of chromosome 6q: precise definition of the breakpoints by microdissection, DNA amplification, and reverse painting. Hum Genet 1996; 97:705-9. [PMID: 8641683 DOI: 10.1007/bf02346176] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Routine chromosomal analysis using GTG-banding alone showed a mosaic terminal deletion of 6q in a 14-week-old boy with developmental retardation, facial anomalies, agenesis of corpus callosum, cleft palate, hypotonia, short neck and pterygium colli, and minor anomalies of hands and feet. Discrepancies between the clinical findings on our patient and those described in the literature on patients having terminal deletions led to a more precise analysis of the karyotype. Reverse painting was performed on normal G-banded metaphases for exact determination of the breakpoints and on metaphases of the patient for evaluation of mosaicism. A DNA library that was obtained by microdissection of three deleted chromosomes 6 was used as a painting probe. Subsequent DNA amplification was performed with the help of topoisomerase-pretreated degenerate oligonucleotide primers. Unexpectedly, the hybridization pattern on normal metaphase chromosomes revealed an interstitial deletion with breakpoints at 6q25.1 and 6q27 instead of a terminal deletion. Hybridization on metaphases of the patient showed one deleted chromosome 6 in all metaphases analyzed at a higher resolution rather than mosaicism as previously assumed [karyotype, 46,XY,del(6)(q25.1 --> q27)]. We assume that in the single cases of 6q- described in the literature the deletions are misclassified. This might be due to difficulties in distinguishing between interstitial and terminal deletions at 6q and in precisely defining chromosomal breakpoints after GTG-banding alone.
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Affiliation(s)
- N Rubtsov
- Institute of Human Genetics and Anthropology, University Jena, Germany
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11
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Dawson AJ, Marles SL, Harman CR, Phillips S, Menticoglou S. Prenatal diagnosis of ring chromosome 6. Prenat Diagn 1995; 15:872-4. [PMID: 8559761 DOI: 10.1002/pd.1970150915] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
An amniocentesis was performed on a gravida 1, para 0 23-year-old female because of high maternal serum alpha-fetoprotein and nuchal thickening/cystic mass apparent on the fetal ultrasound. Detailed ultrasound examination revealed multiple anomalies including brain abnormalities. The fetus was found to have a mosaic female karyotype: 45,XX, - 6/46,XX,r(6) (p25q27) (62 per cent:38 per cent). This is the first report of a prenatally diagnosed case of ring chromosome 6.
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Affiliation(s)
- A J Dawson
- Department of Pediatrics and Child Health, University of Manitoba, Winnipeg, Canada
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12
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Palmer CG, Bader P, Slovak ML, Comings DE, Pettenati MJ. Partial deletion of chromosome 6p: delineation of the syndrome. AMERICAN JOURNAL OF MEDICAL GENETICS 1991; 39:155-60. [PMID: 2063917 DOI: 10.1002/ajmg.1320390208] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Here we summarize the clinical findings of five new patients and nine patients reported in the literature with deletions of the short arm of chromosome 6. The del(6p) syndrome appears to include the following clinical findings: mental retardation, microcephaly, abnormal sutures, broad nasal bridge, various eye and ear abnormalities, a short neck with excess skin folds, and a normal birth weight and length.
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Affiliation(s)
- C G Palmer
- Department of Medical Genetics, Indiana University School of Medicine, Indianapolis 46202-5251
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13
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Kormann-Bortolotto MH, Farah LM, Soares D, Corbani M, Müller R, Adell AC. Terminal deletion 6p23: a case report. AMERICAN JOURNAL OF MEDICAL GENETICS 1990; 37:475-7. [PMID: 2260591 DOI: 10.1002/ajmg.1320370410] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We report on a girl with cleft lip and cleft palate, antimongoloid slant of the palpebral fissures, umbilical hernia, skeletal anomalies, partial syndactyly, hypertonia with increased deep tendon reflexes, psychomotor and growth retardation, and other congenital anomalies. Cytogenetic studies demonstrated a 46,XX,del(6)(qter----p23:) chromosome constitution.
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14
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Zurcher VL, Golden WL, Zinn AB. Distal deletion of the short arm of chromosome 6. AMERICAN JOURNAL OF MEDICAL GENETICS 1990; 35:261-5. [PMID: 2309766 DOI: 10.1002/ajmg.1320350223] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We report on a patient with deficiency of distal 6p and compare the clinical and cytogenetic findings in this child with those of three previously reported patients who had similar deletions. Distal del(6p) appears to be associated with a relatively non-specific phenotype, with the possible exception of unusual congenital eye findings. This apparent association of congenital eye defects with distal del(6p) was supported by comparison with patients having other deletions of chromosome 6, particularly those with ring chromosome 6.
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Affiliation(s)
- V L Zurcher
- Department of Pediatrics, Case Western Reserve University, Cleveland, Ohio
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15
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Shen-Schwarz S, Hill LM, Surti U, Marchese S. Deletion of terminal portion of 6q: report of a case with unusual malformations. AMERICAN JOURNAL OF MEDICAL GENETICS 1989; 32:81-6. [PMID: 2705486 DOI: 10.1002/ajmg.1320320117] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
We present the necropsy findings of a 21-week-gestation male fetus with deletion of the terminal portion of long arm of chromosome 6 [46,XY,del(6)(q23----qter)]. Major anomalies include intrauterine growth retardation, facial anomalies, nuchal cyst, scoliosis, bilateral diaphragmatic hernias, persistent common atrioventricular canal, absent olfactory bulbs and agenesis of corpus callosum. In aberrations of chromosome 6q, patients usually have psychomotor retardation, somatic growth failure, and facial anomalies; nuchal cyst and bilateral diaphragmatic hernias have not yet been described.
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Affiliation(s)
- S Shen-Schwarz
- Department of Pathology, Magee-Womens Hospital, Pittsburgh, Pennsylvania
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16
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van Swaay E, Beverstock GC, van de Kamp JJ. A patient with an interstitial deletion of the short arm of chromosome 6. Clin Genet 1988; 33:95-101. [PMID: 3359674 DOI: 10.1111/j.1399-0004.1988.tb03418.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The clinical history and subsequent progress of a child with an interstitial deletion in the short arm of chromosome 6 is described. This abnormality coupled with a reduced Hageman factor (Factor XII) led to an earlier publication which suggested that this gene was localized to the breakpoint region involved. A review of similar phenotypes from the literature is presented.
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Affiliation(s)
- E van Swaay
- Juliana Children's Hospital, The Hague, The Netherlands
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17
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Chitayat D, Hahm SY, Iqbal MA, Nitowsky HM. Ring chromosome 6: report of a patient and literature review. AMERICAN JOURNAL OF MEDICAL GENETICS 1987; 26:145-51. [PMID: 3544845 DOI: 10.1002/ajmg.1320260122] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
A patient with ring chromosome 6 had most of the manifestations previously reported in this syndrome and also had albinoid fundi and unilateral aniridia, findings not previously described. In most peripheral leukocyte metaphases analyzed, one chromosome 6 was replaced by a monocentric ring chromosome with deletion of the 6p and 6q. Fifteen other patients with a ring chromosome 6 have been reported. The most frequent findings were mental retardation, prenatal and postnatal failure, epicanthal folds, flat nasal bridge, short neck, apparently low-set and/or malformed ears, microphthalmia, and micrognathia. Studies of coagulation Factors XII and XIII and of the P blood group for possible assignment on distal 6p and 6q did not provide evidence for localization of the genes for these factors on the pter----p24 part of chromosome 6.
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18
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Levin H, Ritch R, Barathur R, Dunn MW, Teekhasaenee C, Margolis S. Aniridia, congenital glaucoma, and hydrocephalus in a male infant with ring chromosome 6. AMERICAN JOURNAL OF MEDICAL GENETICS 1986; 25:281-7. [PMID: 3777023 DOI: 10.1002/ajmg.1320250212] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
A premature infant with unilateral aniridia and congenital ectropion uveae, contralateral Rieger anomaly, bilateral congenital glaucoma, and hydrocephalus was found to have ring chromosome 6. The findings are consistent with multiple manifestations of a neural crest-derived maldevelopment of the anterior segment and central nervous system. Comparison with the 14 previously reported cases of ring chromosome 6 illustrates the phenotypic variability of this syndrome.
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19
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Peeden JN, Scarbrough P, Taysi K, Wilroy RS, Finley S, Luthardt F, Martens P, Howard-Peebles PN. Ring chromosome 6: variability in phenotypic expression. AMERICAN JOURNAL OF MEDICAL GENETICS 1983; 16:563-73. [PMID: 6660249 DOI: 10.1002/ajmg.1320160413] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
We present four children with a ring chromosome 6. Clinically, these cases are quite variable. A review of ten previously reported cases also suggests difficulty of phenotype-karyotype correlation in patients with a ring 6.
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20
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Abstract
A study of the ring chromosome 13 syndrome is presented with detailed clinical and cytogenetic features of three new unrelated cases. The clinical limits of this syndrome can now be defined. An analysis of these cases together with those in the literature indicates that the syndrome forms a continuous spectrum, and no further taxonomic subdivision is possible at this stage of knowledge. The chromosome breakpoints in the first two cases are 13p11 and 13q32 and in the third case 13p11 and 13q33 or 13q34. All described cases of the ring 13 syndrome have breakpoints within the region bounded by bands 13q21 to 13q34. All rings are negative for silver banding. Peripheral blood cultures showed an average of 88% of metaphases to be 46,XX,r(13), with the remaining 12% manifesting either random loss or ring duplication. The rings vary in size and show a variable number of centromeres. An estimate of the birth incidence of this condition in the Anglo-Saxon population is 1 in 58,000. Parents of affected children are clinically and cytogenetically normal, the rings in affected offspring being meiotic in origin.
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Abstract
An 8-year-old child with a ring chromosome 7 is presented, the first female and the fourth such individual to be described. The associated anomalies were rather benign: she presented with short stature, minor skeletal alterations, and normal intelligence. The only truly striking feature was the presence of multiple large, pigmented naevi, suggestive of a hamartomatous origin, but unlike those typical of any particular syndrome. Though other ring 7 patients have had naevus flammeus, and one had café-au-lait spots, our proband is the first with an anomaly of chromosome 7 to have such extensive lesions. These four cases of ring 7, which show great phenotypic variation, are reviewed, and the clinical presentation of the proband is also compared with that of patients suffering from terminal, interstitial and translocation-derived 7p and 7q deletions. The formation and behavior of ring chromosomes are discussed, as are the cytogenetic factors which may influence their phenotypic expression.
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Nishi Y, Yoshimura O, Ohama K, Usui T. Ring chromosome 6: case report and review. AMERICAN JOURNAL OF MEDICAL GENETICS 1982; 12:109-14. [PMID: 7091194 DOI: 10.1002/ajmg.1320120115] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
A ring chromosome 6 was identified in an apparently healthy girl with short stature and microcephaly. Of 100 peripheral lymphocyte metaphases analyzed, chromosome 6 was replaced in 73% by a monocentric ring chromosome, in 10% by a dicentric, in 1% by a tricentric, and 3% by two rings. Thirteen other cells were 45,XX,-6, which may represent 46,XX,r(6)/45,XX,-6 mosaicism. The breakpoints were located on bands p24 or p25 and q26 or q27. Eight other patients with a ring chromosome 6 have been reported. The most characteristic findings in subjects with a ring chromosome 6 are mental retardation and eye and ear abnormalities, none of which were present in our patient.
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