Detection of a de novo duplication of 1q32-qter by fluorescence in situ hybridisation in a boy with multiple malformations: further delineation of the trisomy 1q syndrome.

We report a dysmorphic boy with a de novo partial trisomy 1q. The boy has microcephaly, bilateral cleft lip and palate, low set and dysmorphic ears, brain anomalies, pulmonary stenosis, duodenal obstruction, dysplastic kidneys, and bifid thumbs. The trisomic segment 1q32-qter is duplicated with an inverted insertion at 1p36.3. The aberration was initially detected at amniocentesis and confirmed and defined by GTG banding, chromosome microdissection, and FISH on postnatal blood samples. The parents had normal karyotypes. De novo partial duplications of chromosome 1q have rarely been reported. Comparison of our patient with other published pure trisomy 1q cases showed similarities which allowed the further delineation of the trisomy 1q syndrome.     

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.     

Cleft palate and complex chromosome rearrangements

Two of three unrelated children with de novo congenital complex chromosome rearrangements (CCR) with more than four chromosome breaks had cleft lip and palate as one of several congenital anomalies. In patient 1, unilateral complete cleft of the primary and secondary palates accompanied severe ectrodactyly, bilateral posterior choanal atresia and several minor congenital anomalies. Karyotypes of peripheral lymphocytes and skin fibroblasts showed five derivative chromosomes with six break points. There were two translocations, t(2;5), t(3;11) and an interstitial deletion, del(13)(q12q14). Patient 2 had a bilateral complete cleft of the lip and palate, in addition to slow pre- and postnatal growth and minor congenital anomalies. Peripheral lymphocytes and palatal mucosa fibroblasts karyotypes showed five derivative chromosomes with six break points. A partial deletion of 10p, two translocations, t(2;3), t(7;18) and an inversion of the derivative chromosome 2 were present. In both patients, a "major catastrophe" of unknown etiology in one of the parental gametes appeared to be the event leading to the stable CCR without evidence of persistent chromosome instability. All four parents had normal karyotypes. The presence of palatal clefts in these patients indicates that dysmorphologists and pediatricians have to consider CCR whenever taking care of a patient with cleft palate, particularly if additional anomalies, no matter how subtle, are present. The detection and interpretation of the latter anomalies are essential for the diagnosis and management of these patients. Accurate cytogenetic diagnosis determines the short- and long-term prognosis and facilitates genetic counseling in regard to life-span, quality of life and reproductive plans of patients and parents.     

A new case of the trisomy 9p syndrome: Report of a patient with unusual chromosome findings (46,XX/47,XX, + i (9p)) and a peculiar congenital heart defect

A girl is described for whom an unusual chromosome constitution was found and who had a peculiar congenital heart defect. The girl showed the main clinical features of the trisomy 9p syndrome, such as psychomotor retardation, microcephaly and brachycephaly, enophthalmos, antimongoloid eye slant, hypertelorism, abnormal ears, a globulous nose, downward slanting mouth, hypoplasia of phalanges and abnormal palmar creases. In addition, the girl had an incomplete harelip, a cleft palate and a peculiar congenital heart defect, a ventricular septal defect with pulmonary valve stenosis and a marked hypoplasia of the pulmonary trunk, including the bifurcation. Chromosome analysis revealed a mosaicism with normal and abnormal mitoses (47 chromosomes). The extra chromosome was a metacentric E16–like chromosome, which on the basis of the G, R, Q and Giemsa-11–banding could be identified as an isochromosome of the short arm of chromosome 9 (46,XX/47,XX,+ i (9) (pter⇛cen⇛pter)). The patient consequently had a partial tetrasomy of the short arm of chromosome 9.     

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. Am. J. Med. Genet. 84:132–136, 1999. © 1999 Wiley-Liss, Inc.     

Partial trisomy 9--further delineation of the phenotype

A patient with partial trisomy 9 (47,XX,+9pter----q22.1) had bilateral cleft lip and cleft palate, enophthalmos, severe micrognathia, small, apparently low-set ears, and dislocatable knees. The phenotypic findings are compared with those of other documented cases of total trisomy 9.     

Maternal age in Down syndrome

A patient with partial trisomy 9 (47,XX,+9pter→q22.1) had bilateral cleft lip and cleft palate, enophthalmos, severe micrognathia, small, apparently low-set ears, and dislocatable knees. The phenotypic findings are compared with those of other documented cases of total trisomy 9.     

Phenotype-karyotype correlation in patients trisomic for various segments of chromosome 13.

Analysis of clinical and cytogenetic findings taken from 62 published cases of partial trisomies of chromosome 13 showed that 15 had partial trisomy for the proximal long arm and 47 had trisomy for the distal long arm. Persistence of fetal haemoglobin (Hb F), increased projections of polymorphonuclear leucocytes (PMN), depressed nasal bridge, cleft lip/palate, and clinodactyly were more frequent in patients with proximal trisomy 13. In the distal trisomy group, the common features included haemangioma, bushy eyebrows, long curled eyelashes, prominent nasal bridge, long philtrum, thin upper lip, highly arched palate, and hexadactyly. In addition, several other features were common to both the groups, often showing inconsistency even when the same segment was in trisomy. The influence of the second aneusomy as the most likely cause for such inconsistent and overlapping phenotypes is discussed in view of the fact that 42 of 62 cases were derived from a balanced translocation carrier parent.     

Identification of two de novo partial trisomies by comparative genomic hybridization

We report the use of comparative genomic hybridization (CGH) to define the extra chromosome region present in two de novo partial trisomies 15q25-qter and Xp21-pter, which could not be clarified by conventional G-banding. Investigation with fluorescence in situ hybridization (FISH) revealed that the partial trisomy corresponded to an unbalanced translocation between Y and 15 chromosomes in 1 patient and an unbalanced X/X reorganization in the other patient. The combination of classical karyotyping, CGH, and FISH is useful for the identification and characterization of partial trisomies in clinical diagnostic laboratories, in order to delineate the chromosome regions implicated in specific clinical disorders.     

The phenotypic and cytogenetic spectrum of partial trisomy 9

A new patient with trisomy for the chromosome segment 9pter----q22 is compared to 19 previously reported cases of partial trisomy 9. Manifestations such as microcephaly, prominent nasal root, bulbous nose, and down-turned corners of the mouth are common to patients with trisomic segments extending from 9p21 to 9q13, while intra-uterine growth retardation, cleft lip/palate, skeletal anomalies, and heart defects are more common with trisomic segments extending through 9q22-9q32. A graphic method illustrates this progression in the partial trisomy 9 malformation spectrum as the triplicated chromosome region extends from bands 9p21 to 9q32. More severe and random defects are observed with complete trisomy 9 or tetrasomy 9p, suggesting an extreme excess of material greatly increases developmental variability.     

Beckwith-Wiedemann syndrome due to 11p15.5 paternal duplication associated with Klinefelter syndrome and a "de novo" pericentric inversion of chromosome Y

We report on an infant who had been prenatally diagnosed with Klinefelter syndrome associated with a "de novo" pericentric inversion of the Y chromosome. A re-evaluation at 3 years of age suggested that he was also affected by Beckwith-Wiedemann syndrome (BWS). Karyotype was repeated and fluorescence in situ hybridisation (FISH) analysis revealed trisomy for 11p15.5-->11pter and a distal monosomy 18q (18q23-->qter). Parental cytogenetic studies showed that the father carried a balanced cryptic translocation between chromosomes 11p and 18q. Furthermore, the child had an extra X chromosome and a "de novo" structural abnormality of chromosome Y. Thus, his karyotype was 47,XX, inv (Y) (p11.2 q11.23), der(18) t (11;18) (p15.5;q23) pat. ish der(18) (D11S2071+, D18S1390-). Two markers on the X chromosome showed that the extra X of the child was paternally inherited. No deletions were observed on the structurally abnormal Y chromosome from any of the microsatellites studied. Clinical findings of patients with BWS due to partial trisomy 11p reveal that there is a distinct pattern of dysmorphic features associated with an increased incidence of mental retardation when comparing patients with normal chromosomes. This fact reinforces that FISH study have to be performed in all BWS patients, specially in those with mental retardation since small rearrangements cannot be detected by conventional cytogenetic techniques.     

Small extra ring chromosome derived from chromosome 10p: clinical report and characterisation by FISH.

We present a case with a small extra ring chromosome which was found in 66% of lymphocytes on routine cytogenetic examination. FISH analyses, using centromere specific and single copy probes, showed that the extra ring chromosome was derived from the most proximal part of 10p, close to the centromere. The patient has a unilateral cleft lip and palate, mild dysmorphic features, and mild mental retardation. Only a limited number of extra ring chromosomes have been characterised so far. To our knowledge, this is the first reported patient with an extra ring chromosome derived from chromosome 10p.     

Two cases of partial trisomy 21 (pter-q22.1) without the major features of Down syndrome

We report two cases of partial trisomy 21 with clinical features distinct from Down syndrome (DS). These patients presented with moderate mental retardation and short stature, but the typical facial appearance of DS was not observed. Each patient had a similarly sized extra chromosome 21. We performed FISH analysis to examine whether deletions of reported approximately 5 Mb DS critical region (DSCR) might be associated with unusual clinical features in these cases. The results showed that each of their extra chromosomes 21 contained a distal part of chromosome 3p or 14q at the telomeric region of chromosome 21q. The translocation breakpoint of 21q for each patient was located on the centromeric side of DSCR (DSCR was deleted) and the sizes of partial trisomy 21 in respective patients are approximately 34.5 (21pter-q22.12) and approximately 33.0 Mb (21pter-q22.11). In one patient, the additional region of the short arm of chromosome 3 was 3pter-p26.1 from maternal origin, measuring approximately 9 Mb in size. The second patient had an extra 14q32.1-qter of maternal origin, measuring approximately 14 Mb in size. These are one of the shortest partial distal trisomy among reported cases. Taken together, two patients with partial trisomy 21 lack all of DSCR on 21q22, and their distinct clinical features are likely caused by the genes located at 21pter-q22.1 and the distal part of chromosome 3p or 14q.     

Abnormal chromosome 9 in a neonate program. Report of three cases

We describe three cases with abnormal chromosome 9. Patient 1 shows translocation in a homologous chromosome, with a karyotype of 46,XX,t(9;9)(9pter----cen----9pter; 9qter----cen::9q13----9qter), 1qh+. This case has a variety of anomalies, including brain anomalies. Patient 2 shows a partial trisomy 9p with a karyotype of 47,XY,+del(9)(pter----q11:). The patient has the typical clinical features of 9p trisomy syndrome. Patient 3 is unique because of partial 9p tetrasomy mosaicism without phenotypic abnormalities; the karyotype is mos 46,XY/47,XY,+dic(9)(pter----cen----q21::q21----cen----pter).     

Developmental abnormalities associated with long arm deletion of chromosome No. 6

A patient is reported who had a partial terminal deletion of the long arm of chromosome No. 6. His clinical findings included development delay, failure to thrive, neurologic abnormalities, and multiple congenital malformations. Among the malformation were unusual facial features, cleft palate, atrial septal defect, and abnormalities of the external genitalia. The patient's features are compared with others who may have material deleted from the long arm of chromosome No. 6.     

Apparently nonmosaic trisomy 22: clinical report and review

We report on apparently nonmosaic trisomy 22 in a liveborn girl with multiple congenital anomalies. The abnormalities were growth retardation; microcephaly; hypertelorism; epicanthic folds; anti-mongoloid slant; apparently low-set, malformed ears; highly arched, cleft palate; short webbed neck; and hypoplastic nails. The extra 22 was found to be of maternal origin by chromosome polymorphism.     

Trisomy 22. Two new cases and delineation of the phenotype.

Two unrelated children, not affected with Down's syndrome, with strikingly similar phenotypes and an extra G-like chromosome are presented. Quinacrine and trypsin-Giemsa banding identified the extra chromosome as No. 22. The phenotype of these patients and the review of 15 additional similar cases from the literature permit a definition of the cardinal features of trisomy 22; mental and growth retardation, microcephaly and craniofacial asymmetry, strabismus, beaked and prominent nose, long philtrum, cleft palate, micrognathia, large low set ears with preauricular tags and/or pits, long slender fingers, congenital heart disease, inguinal hernia, and hip dislocation.     

Tetrasomy 21 pter→q21.3 due to an extra +dic(21;21)mat in a severely psychomotor-retarded female patient without Down syndrome phenotype

Complete or partial tetrasomy 21 has been reported only in rare cases. We report a Japanese female patient with tetrasomy 21 due to an extra chromosome derived from chromosome 21 (Chr21). The patient had severe psychomotor retardation without Down syndrome (DS) phenotype; she showed short stature, microcephaly, round face, cleft lip and palate, and other dysmorphic features. The chromosome analyses for the patient detected an extra dicentric Chr21 consisting of two partial Chr21 copies fused together within their long arms. Her karyotype was revealed to be 47,XX,+dic(21;21). Allelic ratios of heterozygous SNPs observed in the patient indicated the maternal origin of the extra Chr21. Copy number and structural variant analyses using whole genome sequencing data indicated that the distal breakpoint of the dicentric Chr21 was located within 21q21.3 and that the extra Chr21 did not simply consist of inverted duplications of the pter→q21.3 region, but likely contained multiple partial deletions, duplications, and inversions within it. Fluorescence in situ hybridization results were consistent with the karyotype and genomic analyses. The patient's lack of DS phenotype turned out to be due to the normal copy number of the DS critical region (21q22.13–22.3). A possible molecular mechanism leading to the complex genomic rearrangements in the tetrasomic region consists mainly of breakage-fusion-bridge cycles with an unequal crossing-over event.     

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

The authors report on a young girl with generalized developmental deficits originally thought to be caused by an unusual reaction to DPT vaccination. At the age of 4(1/2) years, chromosome analysis showed that the terminus of the short arm of chromosome 9 had extra material believed to originate from 7p terminus, thus she was considered to be trisomic for a segment of 7p and monosomic for a small portion of 9p [46,XX,der (9), t(7;9)(p15;p24)]. Ten years later, molecular cytogenetic testing using fluorescence in situ hybridization (FISH) confirmed that the extra chromosomal material represented partial trisomy 7p. The proposita had a high and large forehead, hypertelorism, and broad nasal bridge, findings seen in most individuals with trisomy 7p. Long-term follow-up showed the presence of hypothyroidism, obesity, and cerebral palsy. A review of all published cases of trisomy 7p with focus on associated complications suggests a well-defined pattern of abnormalities characterized by musculoskeletal, cardiovascular, neurological, genital, and ocular abnormalities in decreasing frequency. At least one-third of affected individuals died in infancy and close to half had severe mental retardation. FISH was essential in the confirmation of the cytogenetic abnormality and further delineation of the chromosomal disorder.