De novo tandem duplication 9p (p12----p24) with normal GALT activity in red cells

Prenatal diagnosis of maternal partial trisomy 9p23p24.3 and 14q11.2q21.3 in a fetus: a case report

Objective

This study aimed to report a fetus with maternal partial trisomy 9p and 14q and the phenotype detected in ultrasound.

Methods

The chromosome rearrangements in the fetus were characterized by G-banding and chromosome microarray analysis based on single nucleotide polymorphism (SNP) array of cultured amniocytes and compared with the parents’ karyotypes.

Results

The fetal abnormal karyotype was 47,XY,+der(14)(9;14)(p23;q22). The SNP array revealed a duplicate 11.8-Mb 9p23-p24.3 fragment and a duplicate 29.6-Mb 14q11.2-q21.3 fragment. The peripheral blood karyotype of the mother was 46,XX,t(9;14)(p23;q22), while the father’s was normal at the level of 300~400 bands. A high-resolution karyotype analysis conformed the same abnormality of the mother at the level of 550~650 bands. These results indicated that the fetal chromosomal abnormality probably derived from the mother. The fetal nuchal translucency thickness was 3.5 mm, and the fetal heart was detected with around 1.0-mm ventricular defect by the ultrasound examination at 12-week gestation. The couple decided to terminate the pregnancy. They opted for in vitro fertilization and embryo transfer for the fourth pregnancy, which was successful.

Conclusions

The SNP array combined with cytogenetic analysis was particularly effective in identifying abnormal chromosomal rearrangements. These methods combined with the existing database information and fetal ultrasonography might provide a comprehensive and efficient way for the prenatal assessment of fetal situations. Preimplantation genetic diagnosis might effectively assist those women with an adverse pregnancy history in their next pregnancy.

De Novo Duplication of Chromosome 9p in a Female Infant: Phenotype and Genotype Correlation

Trisomy 9p syndrome is the fourth most frequent chromosome aberration seen in infants. Duplication of the critical region 9p22p24 leads to mental retardation, psychomotor delay, and craniofacial and digital anomalies. We report a 2-year-old Ecuadorian girl with Trisomy 9p syndrome. Although her phenotype shares characteristics of Noonan syndrome, Giemsa trypsin banding technique shows there is an extra chromosomal segment on chromosome 14, and array analysis shows that it belongs to a duplication of 38 Mb of 9p13.1p24.3. Fluorescence in situ hybridization analysis detected three signals from 9p chromosome. The duplication is de novo, being another unique case of the few reported in the literature.

Insulin-like growth factor type 1 deficiency in a Moroccan patient with de novo inverted duplication 9p24p12 and developmental delay: a case report

Background

9p duplication is a structural chromosome abnormality, described in more than 150 patients to date. In most cases the duplicated segment was derived from a parent being a reciprocal translocation carrier. However, about 15 cases with de novo 9p duplication have been reported previously. Clinically, this condition is characterized by mental retardation, short stature, developmental delay, facial dysmorphism, hand and toe anomalies, heart defects and/or ocular manifestations.

Case presentation

We report here the case of a 2-year-old Moroccan girl with a de novo duplication of 9p24 to p12. Clinical manifestations included failure to thrive, psychomotor delay, microcephaly, dysmorphic features, equinus feet, and umbilical hernia. Further clinical investigations showed an insulin-like growth factor type 1 deficiency. Banding cytogenetics identified a derivative chromosome 9, with an abnormally elongated short arm. Molecular cytogenetics based on multicolor banding probes characterized an inverted duplication 9p24 to p12 involving several genes especially an insulin-like growth factor binding protein named insulin-like growth factor binding protein-like 1, which seemed to be overexpressed, leading to the insulin-like growth factor deficiency in our patient.

Conclusions

This study showed that insulin-like growth factor type 1 deficiency can be another feature of 9p duplication, suggesting a likely involvement of insulin-like growth factor binding protein-like 1 overexpression in growth delay. However, further studies of the gene expressions are needed to better understand the phenotype-karyotype correlations.

Clefting in trisomy 9p patients: genotype-phenotype correlation using microarray comparative genomic hybridization

Duplication 9p syndrome (partial trisomy 9p) is characterized by craniofacial anomalies, mental retardation, and distal phalangeal hypoplasia. Here, we present a female patient with microcephaly and incomplete bilateral cleft lip and palate, whose initial cytogenetic analysis revealed a de novo trisomy 9p. The patient, now 21 years old, has persistent microcephaly, craniofacial and hand anomalies, history of a seizure disorder, and global mental retardation. Oligonucleotide-based array comparative genomic hybridization was performed and revealed partial trisomy 9p21.1->9pter and a deletion of 9p12.1 to 9p11.2. Our case supports the utility of array comparative genomic hybridization for the precise characterization of chromosomal anomalies and for the ascertainment of genotype-phenotype correlation in patients with partial trisomy 9p.

A de novo marker chromosome derived from 9p in a patient with 9p partial duplication syndrome and autism features: genotype-phenotype correlation

Background

Previous studies focusing on candidate genes and chromosomal regions identified several copy number variations (CNVs) associated with increased risk of autism or autism spectrum disorders (ASD).

Case Presentation

We describe a 17-year-old girl with autism, severe mental retardation, epilepsy, and partial 9p duplication syndrome features in whom GTG-banded chromosome analysis revealed a female karyotype with a marker chromosome in 69% of analyzed metaphases. Array CGH analysis showed that the marker chromosome originated from 9p24.3 to 9p13.1 with a gain of 38.9 Mb. This mosaic 9p duplication was detected only in the proband and not in the parents, her four unaffected siblings, or 258 ethnic controls. Apart from the marker chromosome, no other copy number variations (CNVs) were detected in the patient or her family. Detailed analysis of the duplicated region revealed: i) an area extending from 9p22.3 to 9p22.2 that was previously identified as a critical region for the 9p duplication syndrome; ii) a region extending from 9p22.1 to 9p13.1 that was previously reported to be duplicated in a normal individual; and iii) a potential ASD locus extending from 9p24.3 to 9p23. The ASD candidate locus contained 34 genes that may contribute to the autistic features in this patient.

Conclusion

We identified a potential ASD locus (9p24.3 to 9p23) that may encompass gene(s) contributing to autism or ASD.

Cytogenetic and array-CGH characterization of a complex de novo rearrangement involving duplication and deletion of 9p and clinical findings in a 4-month-old female

Approximately 15 patients with partial trisomy 9p involving de novo duplications have been previously described. Here, we present clinical, cytogenetic, FISH and aCGH findings in a patient with a de novo complex rearrangement in the short arm of chromosome 9 involving an inverted duplication at 9p24→p21.3 and a deletion at 9pter→p24.2. FISH probes generated from BACs selected from the UCSC genome browser were utilized to verify this rearrangement. It is likely that some previously described duplications of 9p may also be products of complex chromosomal aberrations. This report in which FISH and aCGH were used to more comprehensively characterize the genomic rearrangement in a patient with clinical manifestations of 9p duplication syndrome underscores the importance of further characterizing cytogenetically detected rearrangements.

Dandy-Walker malformations in a case of partial trisomy 9p (p12.1→pter) due to maternal translocation t(9;12)(p12.1;p13.3)

We describe a five-year-old proband presented with Dandy-Walker malformations, right microopthalmia, hamstring contractures, undescended testis with absence of testis in right scrotum in addition to typical trisomy 9p clinical features. Routine cytogenetic studies with GTG - banding showed 46,XY,der(12)t(9;12) (p12;q13.3),mat karyotype (trisomy 9p). Chromosomal analysis of the father was normal and phenotypically normal mother had 46,XX,t(9;12)(p12;q13) karyotype. Fluorescence in situ hybridization analysis with single copy probes bA5OIA2 (9p11.2), bA562M8 (12p12.1) and centromere probes (9) showed break point at 9p12.1 region. The gene dosage effect of Chromosome 9p along with environmental factors might be associated with Dandy- Walker malformations in the patient.

20-Mb duplication of chromosome 9p in a girl with minimal physical findings and normal IQ: narrowing of the 9p duplication critical region to 6 Mb

We studied the case of a girl with a partial 9p duplication, dup(9)(p22.1 --> p13.1). Molecular cytogenetics studies defined the chromosome 9 rearrangement as a direct duplication of 20 Mb from D9S1213 to D9S52. Microsatellite analysis demonstrated the presence of a double dosage of the paternal alleles and demonstrated that the duplication occurred between sister chromatids. The patient's phenotype was almost normal, with a few minor anomalies (dolichocephaly, crowded teeth, high arched palate) and normal IQ. The breakpoint's location in this patient and previously reported cases suggest that the critical region for the 9p duplication syndrome lies within a 6-Mb portion of chromosome 9p22 between markers D9S267 and D9S1213.

Characterization of partial trisomy 9p due to insertional translocation by chromosomal (micro)FISH

We describe a family with an insertion 12;9 translocation occurring in a balanced form in a mother and two sons, but in an unbalanced form in the proband, resulting in trisomy of chromosome region 9p22-->9p24. The proband manifests typical features of trisomy 9p; the clinical signs were mental and growth retardation, microcephaly, epicanthus, low-set ears, micrognathia, clinodactyly and hypoplastic phalanges of the fifth fingers, hypoplasia or absence of toenails, and extremely small genitals. The GTG-banded findings were confirmed using (micro)FISH. Intriguingly, the mother and the two carrier sons exhibited major learning difficulties that were not present in the non-carrier sister of the mother: this may be due to a gene disruption or induction of abnormal expression. Dysmorphic features were not present in the three carriers. We compare our clinical and cytogenetic findings with other cases of partial trisomy 9p reported in the literature.

Molecular cytogenetic characterization and origin of two de novo duplication 9p cases

We report on two additional cases with duplication of 9p, minor with facial anomalies and developmental delay. Using fluorescence in situ hybridization and single-copy probes, we showed that the first case was a direct duplication, whereas the second case was inverted. The extent of the direct duplication was defined as 9p12 --> p24 by microdissection and microcloning of the aberrant chromosome and subsequent chromosome-specific comparative genomic hybridization. DNA polymorphism analysis with eight microsatellite markers revealed that the origin of the dup(9p) was maternal in the first case, whereas it was paternal in the second.

Case of partial trisomy 9p and partial trisomy 14q resulting from a maternal translocation: overlapping manifestations of characteristic phenotypes

We report on a female infant with partial trisomy 9p (pter-->p13) and partial trisomy 14q (pter-->q22) resulting from a 3:1 segregation of a maternal reciprocal translocation (9;14)(p13;q22). Both trisomy 9p and partial trisomy 14q have been described as recognized phenotypes with characteristic patterns of anomalies. This patient appears to be the first reported with a partial duplication of both 9p and 14q resulting in an overlapping phenotype including minor facial anomalies, cleft palate, and hand-foot anomalies. However, the facial findings were more pronounced than commonly observed in cases with only one or the other duplicated chromosome regions, resulting in a distinctive appearance.

De novo inverted duplication 9p21pter involving telomeric repeated sequences

We report on clinical and cytogenetic findings in a boy with partial 9p duplication, dup(9)(p21pter). Clinical manifestations included facial and hand anomalies and mental retardation. Fluorescence in situ hybridization (FISH) and comparative genomic hybridization (CGH) were used to characterize further and confirm the conventional banding data. Investigation by FISH using whole chromosome 9 paint probe showed that the additional material was derived from chromosome 9. Using CGH, a region of gain was found in the chromosome segment 9p21pter. YACs and telomeric probes confirmed the duplicated region. Using the all-human telomeric sequences probe, intrachromosomal telomeric signal was noted on the short arm of the abnormal chromosome 9. Mechanism of formation of the duplication, including intrachromosomal telomeric sequences, is discussed.

Molecular cytogenetic characterisation of the first familial case of partial 9p duplication (p22p24)

We report on a father and daughter with a partial 9p duplication, dup(9)(p22p24). Their phenotype, albeit mild, is characteristic of partial trisomy 9p. Fluorescence in situ hybridisation (FISH) was used to characterise further and confirm the G banding finding. This is the first reported instance of trisomy 9p occurring in two successive generations. The duplicated segment in these two patients is among the smallest segments reported. Comparison of our two patients and 144 reported patients with trisomy 9p (partial or complete trisomy) suggests that the 9p22 region may be responsible for the observed phenotype in 9p duplication cases.

Molecular and cytogenetic characterization of 9p- abnormalities

We report on 2 girls with terminal deletion of the short arm of chromosome 9 with concurrent duplication unrecognizable by routine chromosome studies. The phenotype of the patients was not specifically suggestive of the 9p-syndrome in the absence of trigonocephaly and long philtrum as cardinal manifestations. In addition to psychomotor retardation, their manifestations were mild and include upward slant of palpebral fissures and dolichomesophalangy which are characteristic of del(9p). Chromosome abnormalities were de novo in both cases. The two rearranged chromosomes 9 exhibit similar G-banding patterns and suggested the possible duplication of distal 7p. Fluorescence in situ hybridization (FISH) with a chromosome-7 specific library probe indeed identified that one derivative chromosome 9 was the result of a translocation between chromosomes 7 and 9 [der(9)t(7;9)(p15.3;p24] but failed to detect a signal on the other derivative 9. In the second case, the concurrent abnormality was an inverted duplication of proximal 9p and deletion of distal 9p [inv dup(9)(p13-->p22::p22-->qter)] confirmed by FISH using a chromosome 9 specific library probe. FISH clearly identified the origin of these 2 abnormal chromosomes 9 and provided crucial information for clinical evaluation. We emphasize the importance of utilizing updated cytogenetic and molecular techniques in the precise delineation of subtle or complex abnormalities where there are no useful phenotypic clues.

Mosaic dup (9p) diagnosed by fluorescence in situ hybridization (FISH)

We describe a girl with some manifestations of the dup (9p) syndrome. High-resolution Giemsa-banded karyotype of her lymphocytes documented that she was mosaic with 80% of cells being 46,XX, and 20% 46,XX,-20, + der(20;?) (p13;?). The additional material on 20p could not be defined clearly by high-resolution Giemsa banding, as the banding pattern appeared consistent with either distal 9p or distal 13q. In order to make a definitive cytogenetic diagnosis, we used fluorescence in situ hybridization (FISH) with a chromosome 9 specific DNA library to establish that the origin of the additional chromosomal material on chromosome 20 was from 9p. FISH used in this situation enabled us to counsel the family specifically regarding the prognosis and manifestations of distal 9p duplication.

Congenital cardiovascular malformations (CCVM) and structural chromosome abnormalities: a report of 9 cases and literature review

Nine cases of congenital cardiovascular malformations (CCVM) with associated unbalanced structural chromosomal abnormalities were ascertained in a population-based study of heart defects, constituting 0.4% of the 2,103 cases of CCVM in the Baltimore-Washington Infant Study (BWIS). This represents a four-fold increase over the general population rate. In an effort to determine possible phenotype/karyotype correlations, the literature was searched for cases with similar karyotypic abnormalities. This comparison of 223 literature cases of karyotypic abnormalities with nine similar cases ascertained by heart malformation has provided the opportunity to review cardiac defects reported in cases of structural abnormalities of chromosomes 1, 3, 7, 8, 9, 10, 11, 15, and 18. The most common cardiac malformation present in the chromosomal cases was ventricular septal defect (VSD) (39%); similarly VSD is the most common CCVM among children with heart defects, although it is the primary defect in only 20% of the BWIS cases. Among all heart defects in the BWIS, atrial septal defect (ASD) represents 5.5% of all cases, but in cases of 8p duplication, ASD is present in 41%. In addition, 40% of cases of 9p duplication had an ASD. Similarly, 35% of cases of 11q duplication had an ASD. While the suggestion of specific karyotype/phenotype association is premature, information on additional cases might clarify the possibility that genetic determinants related to septum formation may reside on chromosome 8, 9, and/or 11. The variety of chromosomal abnormalities in cases with ventricular septal defect indicates one type of genetic heterogeneity that may be involved in this very common heart defect.

Duplication 9p due to unequal sister chromatid exchange

A case of trisomy 9p syndrome is reported. The karyotype showed a tandem duplication of the short arm and of the inverted heterochromatic block of chromosome 9. Unequal sister chromatid exchange seems to be the only possible cause of this finding.