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.

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.

Neonatal Coronoid Hyperplasia: A Report of a Case and Concepts to Promote Early Diagnosis and Treatment

Limited mouth opening in the neonatal patient is primarily caused by either soft tissue or hard tissue pathologic features. Differentiation between the two can usually be elicited by physical examination with the patient under anesthesia. Limited opening from soft tissue pathologic features can be increased with stretching. In contrast, osseous pathologic features will produce an anatomic stop. Syndromic cases with hard tissue pathologic features are primarily due to coronoid hyperplasia. Our aims are to help clinicians evaluate and identify mandibular hypomobility in the pediatric patient resulting from coronoid hyperplasia and to promote early treatment to improve long-term oral function. We present the case of a 2-month-old male who was born premature at 30 weeks by emergency cesarean section. Examination revealed multiple anomalies, including significant trismus with a maximal opening of 4 mm. A computed tomography scan revealed significant bilateral coronoid hyperplasia. At the age of 90 days, the patient underwent bilateral coronoidectomies with endoscopic guidance under general anesthesia. After resection, the patient was able to open his mouth to 25 mm. This opening was maintained with postoperative physiotherapy. Clinical problems can arise from the potential sequelae of neonatal trismus. Acutely, these problems can range from feeding difficulty and potential malnutrition to aspiration and emergent airway compromise. Long-term consequences include growth restrictions because of malnutrition, speech delay, muscle contracture and atrophy, facial asymmetry, and the risk of infection owing to poor oral hygiene. Information is limited about neonatal treatment of condylar hyperplasia in the published data. Treatment tends to be delayed owing to a late diagnosis and referral, and patients are prone to developing relapse. Postoperative physical therapy will help to prevent relapse and allows for maintenance of the improved jaw range of motion.

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.

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.

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.

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.

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 spectrum of interstitial 7p duplication in mosaic and non-mosaic forms

The phenotypes of a mother and child with a duplication of 7p15-7p22 are described. The mother is mosaic for the cytogenetic abnormality, whereas all cells are affected in her son. Fewer than 5 patients with interstitial 7p duplications are described in the world literature whereas over 30 phenotypic descriptions of individuals with terminal 7p duplication can be found. Authors have suggested that the associated phenotype amounts to a recognizable syndrome. The current cases give further insights into the phenotype that results from pure 7p duplication, both in its mosaic and in its full form. Comparisons are made with previous cases, in the light of the shorter segment involved in the current patients, whose duplication does not extend to pter. This case description will be useful in counseling patients with duplications of 7p and lends support to the existence of characteristic craniofacial features and congenital malformations in this chromosome rearrangement. In addition, as earlier case reports all describe the phenotype associated with non-mosaic partial 7p trisomy, the current observations amount to clear evidence that mosaicism attenuates the phenotype of this rearrangement.

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.