Partial trisomy 2q

An infant with unusual facies and anomalies of brain, heart, and kidney was found to have a simple duplication of the distal long arm of chromosome 2. The clinical features of this case refine the phenotypic spectrum of partial trisomy 2q; prior cases had more complicated chromosomal rearrangements.     

Trisomy 2q and monosomy 11q in the same individual: the importance of considering the deleted segment

A female infant with multiple dysmorphic features and developmental delay was found to have partial duplication of the long arm of chromosome 2 and partial deletion of the long arm of chromosome 11 derived from a paternal balanced translocation, 46,XY,t(2;11)(q33:q25). Clinically, the infant had features of both 2q+ and 11q- syndromes. The importance of considering both the duplicated and deleted segment in unbalanced products resulting from familial translocations is emphasized.     

46,XY, t(3;22)(p2;q13) resuIting in partial trisomy for the short arm of chromosome 3

A familial translocation involving the short arm of chromosome 3 and the long, arm of chromosome 22 is reported, along with an infant with multiple congenital anomalies, which are probably the result of partial trisomy for the short arm of chromosome 3.     

Duplication 7p in a family with t(7;11): association with anomalies of the anterior cranial base

Duplication 7p has been observed in association with several balanced translocations. Of eight previously recorded cases, only one exhibited duplication of the entire short arm of chromosome 7. We report on a newborn infant with multiple congenital anomalies and an abnormal chromosome constitution: 46,XX,-11,+der(11),t(7;11) (p11.1;p15.5)mat. The proposita appeared to possess an isolated duplication of the entire short arm of 7. The patient died at age 4 days because of respiratory complications of meconium aspiration. Clinical and postmortem findings included craniocerebral asymmetry, craniosynostosis of a lambdoid suture, arhinencephaly, hypertelorism, anomalies of the ethmoidal portion of the cranial base, large anterior fontanelle, low set ears, ventricular septal defect (VSD), dysplastic tricuspid and pulmonic valves, hypoplastic genitalia, bilateral dislocated hips, and other minor limb malformations.     

Multiple hemangiomas in a patient with a t(3q;4p) translocation: an infrequent association with Wolf-Hirschhorn syndrome

We report on the clinical phenotype of an infant with a duplication of the terminal portion of the long arm of chromosome 3(q26.3-qter) and a deletion of the terminal portion of the short arm of chromosome 4(p16.3) with multiple hemangiomas and a hamartoma. Patients with deletions of distal 4p have the characteristic features of Wolf-Hirschhorn syndrome (WHS); whereas those with the distal duplication of 3q have a well recognized syndrome with some features resembling Cornelia-de Lange syndrome (CdLS). Neither of these recognized chromosomal anomalies has been reported previously to be associated with multiple hemangiomas or other vascular malformations.     

De novo "pure" partial trisomy (6)(p22.1-->pter) in a chromosome 15 with an enlarged satellite, identified by microdissection

We report on a newborn boy with a congenital heart defect, severe pre- and postnatal growth retardation, feeding problems, facial anomalies and unilateral hydronephrosis. Cytogenetic analysis showed extra chromosomal material on the short arm of one chromosome 15 that at first sight could be mistaken for a chromosomal variant and could not be identified with conventional banding techniques. Chromosome analysis of the parents showed that both had a normal karyotype. Microdissection of five copies of the aberrant chromosome 15, amplification of the dissected chromosomal material by DOP-PCR and subsequent reverse painting was performed and disclosed that the patient had a de novo 46,XY,der(15)(6pter-->6p22.1::15p12-->15qter) karyotype with a "pure" trisomy of chromosome region 6p22.1-->6pter. The associated phenotypic anomalies are compared with other reported cases with a distal duplication of chromosome 6p. Copyright Wiley-Liss. Inc.     

Deletion from the Long Arm of Chromosome 4 (46,XX,4q—) Associated with Congenital Anomalies

A congenitally malformed infant with a partial deletion of the long arm of chromosome 4 identified by Giemsa banding studies is described. The relationship of the anomalies to the chromosome abnormality is discussed.     

De novo “pure” partial trisomy (6)(p22.1→pter) in a chromosome 15 with an enlarged satellite,identified by microdissection

We report on a newborn boy with a congenital heart defect, severe pre‐ and postnatal growth retardation, feeding problems, facial anomalies and unilateral hydronephrosis. Cytogenetic analysis showed extra chromosomal material on the short arm of one chromosome 15 that at first sight could be mistaken for a chromosomal variant and could not be identified with conventional banding techniques. Chromosome analysis of the parents showed that both had a normal karyotype. Microdissection of five copies of the aberrant chromosome 15, amplification of the dissected chromosomal material by DOP‐PCR and subsequent reverse painting was performed and disclosed that the patient had a de novo 46,XY,der(15)(6pter→6p22.1::15p12→15qter) karyotype with a “pure” trisomy of chromosome region 6p22.1→6pter. The associated phenotypic anomalies are compared with other reported cases with a distal duplication of chromosome 6p. © Wiley‐Liss. Inc.     

Partial trisomy 6p due to maternal t(1;6) translocation

Partial trisomy 6p with duplications ranging from 6p21 to 6p25 is emerging as an established syndrome. A case of duplication of segment p22-p25 of the short arm of chromosome 6 as the result of a maternal t (1;6)(q44;p22.2) translocation in a mentally retarded girl with congenital anomalies is reported here. The associated phenotypic anomalies are compared with other reported cases of duplication 6p involving adjacent regions.     

Prenatal Diagnosis of an Inherited Translocation Between Chromosomes No. 9 and 18

A phenotypically normal woman has an apparently balanced reciprocal translocation between chromosomes No. 9 and No. 18 (translocation 9p-; 18p+), which was transmitted in an unbalanced state to an infant and a fetus. In the latter instance, chromosome analysis of cultured amniotic cells disclosed an abnormal karyotype, which was identical to that of the first affected child. The therapeutically aborted fetus was grossly abnormal and resembled the affected child. The physical features noted are those frequently associated with chromosome abnormalities, although not diagnostic for any specific syndrome. We presume that the chromosome abnormality in the affected offspring represents partial duplication of the short arm of chromosome No. 9 and partial deletion of the short arm of chromosome No. 18. No marked resemblance is noted between these cases and reported cases of trisomy 9 or of partial deletion of the short arm of 18.     

Identification of an unusual marker chromosome by spectral karyotyping

We ascertained a newborn girl with multiple congenital anomalies including severe hypotonia, cardiovascular defects, hearing loss, central nervous system anomalies, and facial anomalies. The infant died at 12 days. Cytogenetic analysis showed a de novo supernumerary marker chromosome. Fluorescence in situ hybridization (FISH) with a combination of chromosome specific alpha-satellite probes and an all-human centromere probe failed to show hybridization to the marker, indicating that the marker chromosome lacked detectable alpha satellite sequences. Spectral karyotyping (SKY) was performed and showed that the marker was chromosome 15 in origin. This was confirmed by FISH with a 15q specific subtelomeric probe, which showed hybridization to both ends of the marker chromosome. Based on FISH information and G-banding pattern, the marker was determined to be an inverted duplication of 15q25-qter, leading to partial tetrasomy for chromosome 15. Although the marker chromosome lacked detectable centromeric alpha-satellite sequences, it seemed to have a functional centromere as it is mitotically stable. This observation is consistent with previous studies on acentric marker chromosomes, which suggested that the DNA sequence at the breakpoint could function similarly to alpha-satellite sequences once activated through marker formation. Am. J. Med. Genet. 80:368–372, 1998. © 1998 Wiley-Liss, Inc.     

Duplication 14(q31----qter).

A 29 year old black female with delayed development and multiple congenital anomalies showing a duplication of 14(q31----qter) is presented. Although clinical features associated with partial duplication of the distal long arm of chromosome 14 are variable, there are some features which are distinctive of this chromosomal abnormality. The clinical findings of 14 cases with duplication distal 14q are compared in an effort to define a recognisable syndrome.     

New chromosome aberration: duplication of a large part of chromosome 4q and partial deletion of chromosome 1q

We describe a preterm female infant with multiple anomalies who has a duplication of a large part of 4q and partial deletion of chromosome 1q. Her karyotype was interpreted to be 46,XX,-1,+der(1),t(1;4) (q44;q23 or 24)mat. She is the first patient with an unbalanced translocation involving chromosomes 4 and 1. There is a substantial amount of concordance between the phenotypic features of this patient and those described in the context of partial deletion 1q. The extensive duplication of 4q has no dominant clinical effects in the present infant. These facts support the general concept of much more deleterious effects of deletions versus duplications in human species.     

Two new cases of analphoid marker chromosomes

Supernumerary marker chromosomes (SMCs) without detectable alphoid DNA represent a rare and interesting class of rearranged marker chromosomes. These SMCs are predicted to have a neocentromere and have been referred to as neocentric marker chromosomes (NMCs). We report the molecular cytogenetic characterization of two new cases of neocentromere-containing chromosomes, one on 1q43-44 and one on 15q26. Both cases were examined using fluorescence in situ hybridization (FISH) with various alpha-satellite DNA probes, and no alphoid DNA was detected. In case 1, the NMC originated from the distal long arm of chromosome 1 by chromosomal microdissection and reverse painting. This marker lacked detectable chromosome 1q subtelomeric sequences, and therefore appeared to be a small ring chromosome. After genetic counseling with a high risk for a MCA/MR syndrome (trisomy 1q43 --> q44), the family continued the pregnancy. At age 6 months, the infant demonstrated no congenital or developmental anomalies. This is the first published example of a NMC derived from chromosome 1q. The marker may be one of the smallest, if not the smallest, human NMC reported to date. In case 2, fetal ultrasonography indicated a complex heart defect (abnormal return of lower vena cava, atrial septum malformation) and bilateral hydronephrosis. Molecular cytogenetic analysis showed an inverted duplication of the distal long arm of chromosome 15 (tetrasomy 15q24 --> qter). The pregnancy was terminated. Autopsy demonstrated polycystic left kidney and dysplastic right kidney. Case 2 represents the ninth report of a neocentromere on distal chromosome 15q, suggesting that this region may possibly especially support the formation of neocentromeres.     

Familial partial trisomy 5p resulting from segregation of an insertional translocation

A case of duplication of segment p13-p15 of the short arm of chromosome 5 as the result of an insertional translocation in a mentally retarded girl with congenital anomalies is reported. Some of the apparently balanced carriers of the inverted insertion showed minor congenital anomalies.     

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.     

Recombination aneusomy of chromosome 5 associated with multiple severe congenital malformations

A male infant is described in whom congenital anomalies were recognized prenatally by ultrasound examination. The infant was delivered following spontaneous labor and died approximately 15 min after birth. An autopsy revealed major anomalies in the central nervous system (holoprosencephaly with premaxillary agenesis), the gastrointestinal system (esophageal atresia) and the heart (tetralogy of Fallot). Chromosomal studies revealed recombinant chromosome 5 [46,XY, rec(5), dup q, inv(5)(p15q32)], resulting in partial trisomy 5q and partial monosomy 5p. Cytogenetic investigation of the family revealed a pericentric inversion of chromosome 5 in the father and paternal grandmother, 46,XY (and XX, respectively,) inv(5)(p15q32). The congenital anomalies in this infant are more extensive and severe than previously reported in cases of recombination aneusomy involving chromosome 5.     

Partial chromosome 4 trisomy

A black female infant with multiple congenital anomalies was found to have partial trisomy of chromosome 4, which included all of the short arm and the proximal 20% of the long arm. The chromosomal aberration, to our knowledge, has not been previously reported. Clinically, the infant had a good degree of resemblance to cases of 4p trisomy.     

Trisomy 6q25→6qter in two sisters resulting from maternal 6;11 translocation

Chromosome banding was used to define a partial duplication of the long arm of chromosome 6 (6q25→6qter) in two profoundly affected sisters and to identify their phenotypically normal mother and sister as balanced translocation carriers whose karyotypes were interpreted as 46,XX,t(6;11) (q25;q25). Prominent clinical features included profound mental retardation, hypertelorism, micrognathia, down-turned mouth, dental anomalies, clubfeet, webbed neck, late progressive scoliosis, flexion contractures, and low total finger ridge count. By comparison with published reports, it has been possible to establish a trisomy 6q25→6qter syndrome.     

Duplication 2q33→2q37 due to paternal ins (12;2) translocation

An 18 month-old boy with partial duplication of the long arm of chromosome 2, based on a paternal balanced translocation, 46,XY,ins (12,2)(q23;q33q37), is described and compared with five previously reported cases. These children have in common a short nose with broad flat bridge and small anteverted nostrils, long upper lip, low-set ears, and minor digital anomalies.