Trisomy 7p resulting from 7p15;9p24 translocation: report of a new case and review of associated medical complications

7p22.2 Microduplication: A Pathogenic CNV?

Partial duplication of the short arm of chromosome 7 is a rare chromosome rearrangement. The phenotype spectrum associated with this rearrangement is extremely variable even if in the last decade the use of high-resolution microarray technology for the investigation of patients carrying this rearrangement allowed for the identification of the 7p22.1 sub-band causative of this phenotype and to recognize the corresponding 7p22.1 microduplication syndrome. We report two unrelated patients that carry a microduplication involving the 7.22.2 sub-band. Unlike 7p22.1 microduplication carriers, both patients only show a neurodevelopmental disorder without malformations. We better characterized the clinical pictures of these two patients providing insight into the clinical phenotype associated with the microduplication of the 7p22.2 sub-band and support for a possible role of this sub-band in the 7p22 microduplication syndrome.

Rare combination in an infant patient: trisomy 7p and tetralogy of Fallot

This case report presents an infant patient with the association of trisomy 7p and tetralogy of Fallot(ToF). Patients diagnosed with trisomy 7p should certainly be scheduled for an echocardiographic exam and be scanned for any CHD that may accompany it. The CHD that most frequently accompany this syndrome include atrial septal defect, ventricular septal defect, and patent ductus arteriosis. Yet, it should be known that ToF may also be present, albeit rarely.

Rare combination in an infant patient: trisomy 7p and tetralogy of fallot

This case report presents an infant patient with the association of trisomy 7p and tetralogy of fallot (TEF). Patients diagnosed with trisomy 7p should certainly be scheduled for an echocardiographic exam and be scanned for any CHDs that may accompany it. The CHDs that most frequently accompany this syndrome include atrial septal defect, ventricular septal defect, and patent ductus arteriosis. Yet, it should be known that TEF may also be present, albeit rarely.

Analysis of genetic characteristics of 436 children with dysplasia and detailed analysis of rare karyotype

Chromosomal abnormality is one of the important causes of dysplasia in children. However, due to regional and ethnic differences, the reported rates of chromosomal abnormalities in patients with dysplasia vary greatly. Moreover, the clinical manifestations in children with rare chromosomal diseases were heterogeneous. So, we retrospectively analyzed the karyotype results of 436 children with dysplasia and conducted a detailed analysis of rare chromosomal diseases. The results showed that chromosomal abnormalities were present in 181 of 436 cases. Intellectual disability, dysmorphology, congenital malformations, the disorder of sexual development, and short stature were the main five clinical symptoms in children with chromosomal abnormalities. Moreover, 136 cases of Trisomy 21 (Tri21) were detected, of which 130 were standard Tri21, 5 were robertsonian Tri21, and 1 was chimera type. In addition, 16 cases of rare abnormal karyotype, including complex Tri21, complex Turner syndrome, 4p-syndrome, 18q-syndrome, and 5p-syndrome, were also detected. In summary, chromosome abnormality is one of the important causes of dysplasia in children. Furthermore, prenatal screening and diagnosis could play a great significance in preventing dysplasia in children. In addition, the retrospective analysis of rare cases is valuable for clinical diagnosis and risk assessment of recurrence.

Prenatal diagnosis of partial monosomy 5p (5p15.1→pter) and partial trisomy 7p (7p15.2→pter) associated with cystic hygroma, abnormal skull development, and ventriculomegaly

OBJECTIVE

Prenatal diagnosis of concomitant chromosome 5p deletion syndrome and chromosome 7p duplication syndrome in a fetus with abnormal prenatal ultrasound is presented.

CASE REPORT

A 34-year-old woman was referred for amniocentesis at 22 weeks of gestation because of an irregular-shaped skull, bilateral ventriculomegaly, and nuchal cystic hygroma. Amniocentesis revealed a derivative chromosome 5 with a distal 5p deletion and an addendum of an extra unknown chromosomal segment at the breakpoint of 5p. Cytogenetic analysis of parental bloods revealed a karyotype of 46, XX, t(5;7)(p15.1;p15.2) in the mother and a karyotype of 46,XY in the father. The karyotype of the fetus was 46, XX, der(5) t(5;7)(p15.1;p15.2)mat consistent with partial monosomy 5p (5p15.1→pter) and partial trisomy 7p (7p15.2→pter). A malformed fetus was subsequently delivered with an irregular-shaped skull, a large anterior fontanelle, brachycephaly, hypertelorism, a high and prominent forehead, a large nuchal cystic hygroma, large low-set ears, a short and flattened nose, and micrognathia. Array comparative genomic hybridization analysis of the placenta revealed the result of arr 5p15.33p15.1 (22,179-18,133,327)×1.0, 7p22.3p15.2 (54,215-25,551,540)×3.0, indicating an 18.11-Mb deletion of 5p (5p15.33-p15.1) and a 22.5-Mb duplication of 7p (7p22.3-p15.2). Cord blood sampling revealed a karyotype of 46, XX, der(5)t(5;7) (p15.1;p15.2)mat.

CONCLUSION

Fetuses with 5p deletion syndrome and 7p duplication syndrome may present ventriculomegaly, abnormal skull development, and cystic hygroma on prenatal ultrasound.

Case of 7p22.1 Microduplication Detected by Whole Genome Microarray (REVEAL) in Workup of Child Diagnosed with Autism

Introduction. More than 60 cases of 7p22 duplications and deletions have been reported with over 16 of them occurring without concomitant chromosomal abnormalities. Patient and Methods. We report a 29-month-old male diagnosed with autism. Whole genome chromosome SNP microarray (REVEAL) demonstrated a 1.3 Mb interstitial duplication of 7p22.1 ->p22.1 arr 7p22.1 (5,436,367-6,762,394), the second smallest interstitial 7p duplication reported to date. This interval included 14 OMIM annotated genes (FBXL18, ACTB, FSCN1, RNF216, OCM, EIF2AK1, AIMP2, PMS2, CYTH3, RAC1, DAGLB, KDELR2, GRID2IP, and ZNF12). Results. Our patient presented features similar to previously reported cases with 7p22 duplication, including brachycephaly, prominent ears, cryptorchidism, speech delay, poor eye contact, and outburst of aggressive behavior with autism-like features. Among the genes located in the duplicated segment, ACTB gene has been proposed as a candidate gene for the alteration of craniofacial development. Overexpression of RNF216L has been linked to autism. FSCN1 may play a role in neurodevelopmental disease. Conclusion. Characterization of a possible 7p22.1 Duplication Syndrome has yet to be made. Recognition of the clinical spectrum in patients with a smaller duplication of 7p should prove valuable for determining the minimal critical region, helping delineate a better prediction of outcome and genetic counseling.

Prenatal diagnosis of microdeletion 16p13.11 combination with partial monosomy of 2q37.1-qter and partial trisomy of 7p15.3-pter in a fetus with bilateral ventriculomegaly, agenesis of corpus callosum, and polydactyly

OBJECTIVE

To present a prenatal diagnosis of microdeletion 16p13.11 with partial monosomy of 2q37.1-qter and partial trisomy of 7p15.3-pter in a fetus with bilateral ventriculomegaly, agenesis of corpus callosum, and polydactyly.

CASE REPORT

A 41-year-old well-being Taiwanese, nulligravida woman received amniocentesis at a gestational age of 18 weeks for advanced maternal age. The fetus' karyotype showed 46,XY,der(2)t(2;7)(q36.2;p15.1). Both parents also received cytogenetic examinations and the mother's karyotype revealed 46,XX,t(2;7)(2q36.2;p15.1). High-resolution ultrasound showed the fetus had bilateral ventriculomegaly, agenesis of corpus callosum, and polydactyly of the right hand. After the termination of this pregnancy, the whole genome oligonucleotide-base array comparative genomic hybridization (CGH) by using fetal skin cells demonstrated a 8.44-Mb deletion at 2q37.1 (234602276-243041305), a 22.8-Mb duplication (65558-22869338) at 7p15.3, and an additional 1.32-Mb deletion (14968855-16292235) at 16p13.11.

CONCLUSION

Array CGH is a useful tool not only to discover the genomic imbalance at the breakpoints as well as to detect unexpectedly complex rearrangements in other chromosomes. Our case also provided evidence that genomic aberration at chromosome 16p13.11 involves in the formation of polydactyly.

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

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.

Clinical and molecular characterization of a second case of 7p22.1 microduplication

The use of high-resolution microarray technology for investigation of patients with intellectual disability and/or congenital anomalies provided the unique possibility to identify new microdeletion/microduplication syndromes and discover the dosage sensitive genes, which are implicated in the manifestation of various genetic conditions. Microduplication of the 7p22.1 region, 1.7 Mb in size, has very recently been reported, representing the smallest interstitional 7p duplication, associated with specific facial features and speech delay. We report on a patient with an even smaller 7p22.1 de novo microduplication, 1 Mb in size, detected in a 14.5-year-old patient with mild intellectual disability and similar facial dysmorphism, including macrocephaly, ocular hypertelorism, low-set ears, and other features. There are 15 RefSeq genes included in this duplication. ACTB gene is a strong candidate gene for the alteration of craniofacial development. Further cases with similar duplications will contribute to the delineation of a potential new microduplication syndrome of 7p22.1.

Clinical and molecular characterization of chromosome 7p22.1 microduplication detected by array CGH

A 28-month-old Peruvian male presented with speech delay and unusual facial features including prominent forehead, anteverted nares, ocular hypertelorism, and low-set and posteriorly rotated ears with a unilateral preauricular pit. The patient had poor speech with no other developmental delays. Height and weight were normal, although closure of the anterior fontanel and bone age were delayed. Head circumference approximated the 95th centile for age. Following normal routine chromosome analysis and subtelomeric FISH, whole genome microarray revealed a novel interstitial duplication at 7p22.1, approximately 1.7 Mb in size, and containing 13 OMIM annotated genes. FISH studies on the propositus and his parents confirmed that the duplication had occurred de novo. This finding represents the smallest interstitial 7p duplication reported to date, and does not include genes previously implicated as candidates for a 7p duplication syndrome. Common phenotypic features of 7p duplication include distinctive facies with hypertelorism,large anterior fontanel, and intellectual disability. Based on the findings in our patient, and those in previously reported cases of 7p duplication, we propose that genes within this duplicated interval may have a role in skeletal maturation,craniofacial development, and speech acquisition.

Structural Chromosome Abnormalities Associated with Obesity: Report of Four New subjects and Review of Literature

Obesity in humans is a complex polygenic trait with high inter-individual heritability estimated at 40-70%. Candidate gene, DNA linkage and genome-wide association studies (GWAS) have allowed for the identification of a large set of genes and genomic regions associated with obesity. Structural chromosome abnormalities usually result in congenital anomalies, growth retardation and developmental delay. Occasionally, they are associated with hyperphagia and obesity rather than growth delay. We report four new individuals with structural chromosome abnormalities involving 10q22.3-23.2, 16p11.2 and Xq27.1-q28 chromosomal regions with early childhood obesity and developmental delay. We also searched and summarized the literature for structural chromosome abnormalities reported in association with childhood obesity.

De novo 7p partial trisomy characterized by subtelomeric FISH and whole-genome array in a girl with mental retardation

Chromosome rearrangements involving telomeres have been established as one of the major causes of idiopathic mental retardation/developmental delay. This case of 7p partial trisomy syndrome in a 3-year-old female child presenting with developmental delay emphasizes the clinical relevance of cytogenetic diagnosis in the better management of genetic disorders. Application of subtelomeric FISH technique revealed the presence of interstitial telomeres and led to the ascertainment of partial trisomy for the distal 7p segment localized on the telomeric end of the short arm of chromosome 19. Whole-genome cytogenetic microarray-based analysis showed a mosaic 3.5 Mb gain at Xq21.1 besides the approximately 24.5 Mb gain corresponding to 7p15.3- > pter. The possible mechanisms of origin of the chromosomal rearrangement and the clinical relevance of trisomy for the genes lying in the critical regions are discussed.

Prenatal diagnosis and molecular cytogenetic characterization of de novo partial trisomy 7p (7p15.3→pter) and partial monosomy 13q (13q33.3→qter) associated with Dandy-Walker malformation, abnormal skull development and microcephaly

OBJECTIVE

To present the prenatal diagnosis and molecular cytogenetic characterization of de novo partial trisomy 7p (7p15.3→pter) and partial monosomy 13q (13q33.3→qter) associated with Dandy-Walker malformation (DWM), abnormal skull development, microcephaly and multiple congenital anomalies.

MATERIALS, METHODS AND RESULTS

A 42-year-old woman, gravida 6, para 1, was referred for amniocentesis at 18 weeks of gestation because of her advanced maternal age. Amniocentesis revealed an aberrant derivative chromosome 13, or der(13). The parental karyotypes were normal. Spectral karyotyping showed that the der(13) was derived from a translocation of chromosomes 7 and 13. Fluorescence in situ hybridization using subtelomeric probes revealed three signals of 7pTEL and only one signal of 13qTEL, indicating a translocation between 7p and 13q in the der(13). Array-based comparative genomic hybridization demonstrated partial trisomy 7p (7p15.3-p22.3) and partial monosomy 13q (13q33.3-q34). The karyotype was 46,XY,der(13)t(7;13)(p15.3;q33.3). Polymorphic DNA marker analysis revealed the paternal origin of the aberrant chromosome. Level II ultrasound at 24 weeks of gestation revealed microcephaly, an irregular-shaped skull, DWM, nuchal edema and transposition of the great arteries.

CONCLUSION

Spectral karyotyping, fluorescence in situ hybridization and array-based comparative genomic hybridization are useful for prenatal investigation of the nature of a de novo aberrant derivative chromosome. Partial trisomy 7p (7p15.3→pter) and partial monosomy 13q (13q33.3→qter) can be associated with DWM, microcephaly, abnormal skull development, nuchal edema and cardiovascular defects on prenatal ultrasound.

Duplication 5q and deletion 9p due to a t(5;9)(q34;p23) in 2 cousins with features of Hunter-McAlpine syndrome and hypothyroidism

We report on 2 similarly affected cousins with a compound imbalance resulting from a familial t(5;9)(q34;p23) and entailing both an ∼17-Mb 5q terminal duplication and an ∼12-Mb 9p terminal deletion as determined by G-banding, subtelomere FISH, and aCGH. The proband's karyotype was 46,XX,der(9)t(5;9)(q34;p23)mat.ish der(9)t(5;9)(q34;p23)(9pter-,5qter+).arr 5q34q35(163,328,000-180,629,000)×3, 9p24p23(194,000-12,664,000)×1. Her cousin had the same unbalanced karyotype inherited from his father. The clinical phenotype mainly consists of a distinct craniofacial dysmorphism featuring microcephaly, flat facies, down slanting palpebral fissures, small flat nose, long philtrum, and small mouth with thin upper lip. Additional remarkable findings were craniosynostosis of several sutures, craniolacunia and preaxial polydactyly in the proband and hypothyroidism in both subjects. The observed clinical constellation generally fits the phenotypic spectrum of the 5q distal duplication syndrome (known also as Hunter-McAlpine syndrome), except for the thyroid insufficiency which can likely be ascribed to the concurrent 9p deletion, as at least 4 other 9pter monosomic patients without chromosome 5 involvement had this hormonal disorder. The present observation further confirms the etiology of the HMS phenotype from gain of the 5q35→qter region, expands the clinical pictures of partial trisomy 5q and monosomy 9p, and provides a comprehensive list of 160 patients with 5q distal duplication.

Ultrasound manifestations of unusual trisomies-excluding trisomy 13, 18, and 21: a literature review

Trisomy is the most commonly identified chromosome abnormality, occurring in at least 4% of all clinically recognized pregnancies (1). Most of the trisomies are associated with a single additional chromosome, although 2 other types of trisomic conceptions are occasionally observed, those with 2 additional chromosomes or double trisomy and those with both a normal and trisomic cell line or mosaic trisomies. The adverse effects of trisomy on the phenotype are well established. In this review article, we consider the prevalence of the unusual trisomies (excluding 13, 18, and 21) and present a review of their ultrasound findings.

Partial trisomy and partial monosomy resulting from a reciprocal segregating in a large family

Partial trisomy 7p with partial monosomy 9p is a rare disorder with only 3 cases reported. Both these abnormalities i.e., partial trisomy 7p and partial monosomy 9p result in distinct clinical phenotypes. However, patients with combined 7p trisomy/9p monosomy present with a phenotype consistent with trisomy 7p. We present a fourth case of trisomy 7p/monosomy 9p with long term follow-up and document the medical complications associated with this disorder. Long term follow-up of patients with chromosome abnormalities provides a unique opportunity to document the medical history and complications associated with such abnormalities.

A report of pure 7p duplication syndrome and review of the literature

We report on a case of a 9-month-old female infant with a direct duplication of the 7p13-p22.1 chromosome region diagnosed by combining conventional cytogenetic, FISH, and multicolor banding (MCB) studies. Traditional G-banding detected a partial 7p duplication, which was further demonstrated to be entirely of chromosome 7 origin by using a whole chromosome paint for chromosome 7, and derived from 7p13-p22.1 by MCB. The infant presented with characteristic dysmorphic features, psychomotor retardation, and generalized hypotonia. The phenotypic manifestations of partial 7p trisomy with or without other chromosome involvement are briefly reviewed. Our observations in combination with other cases confirm that 7p trisomy due to dir dup(7p) can be regarded as a defined chromosome syndrome.

Prenatal Diagnosis of a Fetus with Partial Trisomy 7p

We report a prenatal diagnosis of a fetus with partial trisomy 7p. Ultrasonography at 28 weeks of gestation of a 27-year-old multigravid woman revealed a growth-retarded fetus with agenesis of the corpus callosum, enlarged left kidney, single umbilical artery, hypertelorism, depressed nasal bridge, frontal bossing, irregular maxiller alveolar composition, club feet, flexion deformity of the upper extremities and Epstein anomaly. Fetal karyotype was 46,XX,der(9)add(9p24),16qh+. Our results indicated that the fetus had an unbalanced translocation, which resulted in duplication of the proximal segment of 7p. Maternal karyotype was (46,XX,t(7,9)(p15.3,p24),16qh+). Because fetal death occurred at 31 weeks of gestation, induction of labor was performed. An enlarged anterior fontanel and micrognathia were seen during fetal autopsy. Trisomy 7p is related to a well-known clinical picture with a dismal prognosis. Our report showed that the outcome of the affected pregnancy may also be poor. Detection of fetal chromosomal abnormality and parental translocations are essential for counseling of the parents.

A patient with duplication (7)(p22.1pter) characterized by array-CGH

Approximately 40 patients with terminal duplication of the distal short arm of chromosome 7 have been reported, the smallest being dup(7)(p21). We report here on a patient with a smaller duplication, dup(7)(p22.1), detected on G-banding and characterized by array-CGH. We establish phenotype-karyotype correlations with the reported patients with other 7p duplications.

Greater trochanteric stippling in trisomy 7p

Trisomy 7p is a rare condition involving partial or complete duplication of the short arm of chromosome 7. Radiological features include large fontanelles, widened sutures, dolicocephaly and asymmetrical skull. We report a new radiological finding of punctate calcifications in the region of femoral trochanters. This finding has not previously been reported with chromosome 7p duplication.

Mapping genomic deletions down to the base: a quantitative copy number scanning approach used to characterise and clone the breakpoints of a recurrent 7p14.2p15.3 deletion

With the recent advances in genomic research, it has become apparent that a substantial part of human malformation and mental retardation is caused by imbalances in genomic content. Thus, there is an increasing need for versatile methods allowing a detailed mapping and cloning of the actual rearrangements. We have combined the flexibility of real-time quantitative PCR with the knowledge of human genome sequence to perform a copy number scanning in three patients known to harbour a deletion in the 7p14p15 locus. In two of the patients the actual breakpoints were cloned and sequenced, whereas the breakpoint of the third patient was mapped to a region previously predicted to be prone for rearrangements. One patient also harboured an inversion in connection with the deletion that disrupted the HDAC9 gene. All three patients showed clinical characteristics reminiscent of the hand-foot-genital syndrome and were deleted for the entire HOXA cluster. Two patients were also deleted for DFNA5, a gene implicated in dominant nonsyndromic hearing impairment, but neither patient showed signs of reduced hearing capabilities. The described copy number scanning approach is largely independent of the genomic locus and may be a valuable tool for characterising a large spectrum of deletions.

Severe psychomotor retardation in a boy with a supernumerary derivative chromosome resulting in partial trisomy 21 and partial trisomy 7p

We report on a 12-year-old boy with a supernumerary chromosome der(21)t(7; 21)(p21; q21.3)mat, resulting in a partial trisomy 21 and a partial trisomy 7p. The patient has a severe psychomotor retardation. Although he has most of chromosome 21 in three copies, he does not have a phenotype of Down syndrome (DS). In addition to cytogenetic analysis, molecular analysis confirmed that the "DS critical region" on chromosome 21 (21q22) is not present in three copies, since the breakpoint of the partial trisomy 21 was found to be located distal to the marker locus D21S145 but proximal to D21S226. The patient's severe mental retardation is probably due to the small telomeric 7p trisomy, having the breakpoint between markers D7S507 and D7S488. In comparison with previously published cases of partial trisomy 7p, the phenotype of this patient indicates that there is a region around the distal part of band 7p21 that in three copies might contribute to many of the facial features common to patients with partial trisomy 7p.

Phenotypic findings due to trisomy 7p15.3-pter including the TWIST locus

We report on a three-month-old boy with a 46,XY,der(Y)t(Y;7)(p11.32;p15.3) karyotype and growth deficiency, postnatal microcephaly with large fontanels, wide sagittal and metopic sutures, hypertelorism, choanal stenosis, micrognathia, bilateral cryptorchidism, hypospadias, abnormal fingers and toes, and severe developmental delay. FISH studies showed partial trisomy 7p resulting from a de novo unbalanced translocation. The application of molecular probes from the TWIST gene region (7p15.3-p21.1) and probes from the pseudoautosomal region (PAR) demonstrated that the 7p15.3-pter fragment was translocated onto Yp with the breakpoint within approximately 20 kb from the Yp telomere. We discuss the possible role of the TWIST gene in abnormal skull development and suggest that trisomy 7p cases with delayed closure of fontanels can be a result of TWIST gene dosage effect.