Trisomy 1q42→qter in a sister and brother: Further delineation of the “trisomy 1q42→qter Syndrome”

We report on a 22-year-old woman and her 21-year-old brother with mild mental retardation, long face, prominent forehead, retrognathia, and (relative) macrocephaly. At birth they were small for date, their length is now below the 10th centile. Chromosome analysis demonstrated a nearly pure trisomy 1q42→qter in both patients due to unbalanced segregation of a paternal reciprocal balanced translocation 46,XY,t(1;15) (q42;p11). This is the second report of a nearly pure trisomy 1q42→qter. When comparing the manifestations of our patients with those of other reported cases we conclude that the most characteristic clinical manifestations of this syndrome are macrocephaly, prominent forehead, micro/retrognathia, large fontanelle, intrauterine growth retardation, postnatal growth retardation, and mental retardation. © 1995 Wiley-Liss, Inc.     

Inv dup del (1)(pter-->q44::q44-->q42:) with the classical phenotype of trisomy 1q42-qter.

We report on a girl with a trisomy 1q42-q44 due to an inverted duplication of this region, associated with a terminal deletion of the long arm of the rearranged chromosome 1. Both the large duplication (more than 30 cM) and the small deletion were detected by FISH. Complete karyotype was: (46,XX, inv dup(1)(q44q42).ish(dup del 1)(q44q42)(D1S446x2, D1S423x2, tel1q-). The phenotype of the patient is characterized by macrocephaly with prominent forehead, downslanting palpebral fissures, micrognathia, and psychomotor retardation. All these clinical features are the same as observed for the typical trisomy 1q42-qter syndrome. The phenotypic effects of the inversion and the terminal deletion of 1q in addition to the trisomy are discussed here.     

Trisomy (1q) (q42→qter): confirmation of a syndrome

This paper describes for the first time the clinical findings in a case of pure trisomy (1q)(q42----qter). Eight cases involving this trisomy have been reported previously, but these were complicated by additional chromosomal changes, and hence the assignation of a discrete phenotype remained doubtful. The clinical abnormalities reported here, most of which were included amongst others in the previous reports of trisomy (1q)(q42----qter), provide the basis for characterisation of this condition as a syndrome. These changes comprised macrocephaly, prominent forehead, micrognathia, large fontanelle, flat nasal bridge, low-set ears, facial capillary naevi, cardiac defect and small size for gestational age.     

Partial trisomy 1 (q42→ter)

Clinical findings on three closely related, severely malformed infants and a 20-week-old fetus with an identical partial trisomy of chromosome 1 (1q42→ter) have made possible the delineation of a new syndrome. The typical manifestations of this syndrome are: severe intrauterine and postnatal developmental retardation, trigonocephaly with wide sutures and fontanels, characteristic facial features, colobomata of the iris, small hands and feet, and early death.     

Dup(lq)(q42→qter) syndrome: Case report and review of literature

We report on a patient with primordial growth retardation, mental retardation, and minor anomalies (triangular face, open sagittal suture, frontal bossing, telecanthus, upturned nose, micrognathia, and small mouth with downturned corners). The diagnosis of Russell-Silver syndrome (RSS) had been considered but was abandoned when cytogenetic evaluation showed a partial trisomy lq or duplication lq (46,XY,15, + der(15)t(l;15)(q42;qter). Data from another 5 reports of dup(l)(q42→qter) do not allow delineation of a typical syndrome. However, individuals with dup(lq), del(15q), and Russell-Silver syndrome share common manifestations (i.e., low birth weight, growth retardation, triangular face, low set/abnormal ears, micrognathia, renal anomalies). © 1993 Wiley-Liss, Inc.     

Atypical phenotype associated with deletion (15) (pter → q11::q13 → qter)

We report on a 10-year-old boy with an interstitial deletion within the region of bands 15q11 → q13. Authors have associated the manifestation of the Prader-Willi syndrome (PWS) with variable deletions involving the bands q11 → q13. Our patient had atypical manifestations not usually associated with PWS, ie, normal stature, proportionally sized hands and feet, normal genitalia, and was nonambulatory and severely mentally retarded. This case emphasized the clinical diversity seen in proximal 15q deletions in the region considered to be correlated with the PWS.     

Clinical and molecular cytogenetic characterization of two patients with partial trisomy 1q41‐qter: Further delineation of partial trisomy 1q syndrome

We report the clinical and molecular cytogenetic characterization of two patients with partial trisomy 1q. The first patient is a currently 11‐year‐old female proposita with a de novo unbalanced translocation 46,XX,der(8)(8qter‐8p23.3::1q41‐1qter), leading to a partial trisomy 1q41‐qter and a partial monosomy for 8p23.3‐pter. The most prominent clinical features of the girl are a triangular face, almond‐shaped eyes, low‐set ears, short stature with relatively long legs, and mild psychomotor retardation. To our knowledge, the cytogenetic aberration in this girl is the most proximal partial trisomy 1q leading to a mild phenotype. Recently, we identified a second patient with a similar partial trisomy 1q combined with a cri du chat syndrome caused by a de novo unbalanced translocation 46,XX,der(5)(5qter‐5p13.1::1q41‐1qter). Comparison of the phenotype of the two girls as well as with already published trisomy 1q cases was performed, and fluorescence in situ hybridization probes from selected YACs were used to delineate the extent of the partial trisomy in more detail. © 2001 Wiley‐Liss, Inc.     

Girl with combined cellular immunodeficiency,pancytopenia, malformations,deletion 11q23.3 → qter,and trisomy 8q24.3 → qter

We describe here a 3‐year‐old girl demonstrating combined cellular immunodeficiency of B‐ and T‐cells, pancytopenia, multiple anomalies, and severe mental retardation. Cytogenetic analysis and fluorescent in situ hybridization (FISH) indicated an unbalanced translocation of chromosomes 8q and 11q, resulting in monosomy 11q23.3‐qter and trisomy 8q24.3‐qter. The association of cellular immunodeficiency and partial deletion 11q and/or partial trisomy 8q has not been described previously; however, the 11q deletion has been reported with humoral immunodeficiency or pancytopenia. Some one‐third to one‐half of patients with partial monosomy 11q were reported to have pancytopenia, which has been related to the absence of the 11q23‐q24 region. Our case narrows down the critical interval for thrombo‐ or pancytopenia to 11q23.3‐q24 and excludes both the ATM (which resides on 11q23.1) and the MLL genes as possible candidate genes. We are proposing that haploinsufficiency of the NFRKB gene on 11q24‐q25 and/or the ETS‐1 proto‐oncogene on 11q24 may have caused or contributed to the immunodeficiency (decreased levels of B‐ and T‐lymphocytes) in our patient. © 2002 Wiley‐Liss, Inc.     

Subtelomeric familial translocation t(2;7)(q37;q35) leading to partial trisomy 7q35→qter: Molecular cytogenetic analysis and clinical phenotype in two generations

Few patients with trisomy of the most distal region of chromosome 7q have been described. We report on a familial translocation t(2;7)(q37;q35) leading to trisomy 7q35→7qter in a child and her paternal uncle and a minimal deletion of distal 2q as demonstrated by FISH with probes located in the chromosome 2q subtelomeric region. The clinical phenotype included macrocephaly and low‐set ears, also found in other reported patients trisomic for the distal part of chromosome 7q. Phenotypic findings probably useful for the clinical diagnosis include normal size at birth, large head with frontal bossing, low‐set ears of normal shape, small nose and low nasal bridge, feeding difficulties in infancy, and severe neurodevelopmental delay. Am. J. Med. Genet. 93:349–354, 2000. © 2000 Wiley‐Liss, Inc.     

Monosomy 9p24→pter and trisomy 5q31→qter: Case report and review of two cases

Partial deletion of the short arm of chromosome 9 (p24→pter) and partial duplication of the long arm of chromosome 5 (q32→qter) were observed in an abnormal boy who died at age 8 weeks of a complex cyanotic cardiac defect. He also had minor anomalies, sagittal craniosynostosis, triphalangeal thumbs, hypospadias, and a bifid scrotum. Two other infants with similar cytogenetic abnormalities were described previously. These patients had severe congenital heart defect, genitourinary anomalies, broad nasal bridge, low hairline, apparently low-set ears, short neck, and triphalangeal thumbs, in common with our patient. We suggest that combined monosomy 9p23,24→pter and trisomy 5q31,32→qter may constitute a clinically recognizable syndrome. © 1995 Wiley-Liss, Inc.     

Duplication 6q22→qter: Definition of the phenotype

We report on a girl with duplication of 6q22.32 → qter and microcephaly, frontal bossing, facial anomalies, and webbed neck. She has congenital heart disease, renal hypoplasia, and hearing loss along with severe developmental delay. Published reports of seven other patients are reviewed and compared. The most frequent anomalies include microcephaly, abnormal face, webbed neck, congenital heart disease, limb contractures, and developmental delay. Am. J. Med. Genet. 78:123–126, 1998. © 1998 Wiley-Liss, Inc.     

Familial cryptic translocation with del 4q34→qter and dup 12pter→p13 in sibs with tracheal stenosis: Clinical,classical and molecular cytogenetic studies and CGH analyses from archival placental tissues evidencing tertiary trisomy 4 in one abortion specimen

We report on two retarded half‐sibs of different sex and seemingly normal karyotype who had the same syndrome of minor anomalies, heart defect and a distal tracheal stenosis, and who shared a healthy mother. These findings raised suspicions of a cryptic chromosome translocation. A translocation t(4;12)(q34;p13), balanced in the mother and unbalanced in the sibs with loss of terminal 4q and gain of terminal 12p regions, was verified by FISH using whole chromosome painting, subtelomeric and YAC probes. Clinical features could be explained by partial monosomy 4q and partial trisomy 12p. Tracheal stenosis was interpreted as a consequence of the same developmental disturbance leading to esophageal atresia and tracheo‐esophageal fistula. It was attributed to the 4q deletion in which esophageal atresia as also respiratory difficulties and airway obstructions had been described. Paraffin‐embedded placental tissues were available from three of the five abortions of the mother allowing DNA extraction and comparative genome hybridization (CGH). Two of the abortion specimens had the same der(4)t(4;12)(q34;p13) unbalanced translocation as identified in the sibs. In the third abortion specimen, suspicious of triploidy because of partial hydatidiform mole, CGH uncovered a tertiary trisomy 4 resulting from a 3:1 segregation of the translocation chromosomes and their homologs during maternal meiosis I. Differences in CGH results using DNA generated directly or after DOP‐PCR were explained by DNA fragmentation in paraffin‐embedded tissues and unequal amplification. Am. J. Med. Genet. 94:271–280, 2000. © 2000 Wiley‐Liss, Inc.     

Segregation of a familial balanced (12;10) insertion resulting in dup(10)(q21.2q22.1) and del(10)(q21.2q22.1) in first cousins

An interchromosomal insertion in 3 generations of a family was ascertained through two developmentally delayed first cousins. Cytogenetic analysis using G-banding and chromosome painting showed an apparently balanced direct insertion of chromosome 10 material into chromosome 12, ins(12;10)(q15;q21.2q22.1), in the mothers and grandfather of these children. The proposita inherited only the derivative 10 chromosome, resulting in deletion of 10q21.2 → 22.1 while her cousin inherited only the derivative 12, resulting in duplication of 10q21.2 → 22.1. A comparison of the proposita with published deletion cases suggests a pattern of anomalies attributable to deletion of the 10q21 → q22 region: developmental delay, hypotonia, a heart murmur, telecanthus, broad nasal root and ear abnormalities. This is the first report of a nontandem duplication of the 10q21 → q22 region. The phenotype of the cousin with the duplication does not overlap greatly with published tandem 10q duplications. Finally, this report reaffirms the importance of obtaining family studies of patients with interstitial chromosomal abnormalities. Am J. Med. Genet. 69:188–193, 1997. © 1997 Wiley-Liss, Inc.     

Pericentric inversion of chromosome 14 and the risk of partial duplication of 14q (14q31 → 14qter)

Cytogenetic analysis after conventional staining and Q-banding demonstrated a pericentric inversion of chromosome 14 in the mother of a child with a mental retardation/multiple congenital abnormality syndrome and an abnormal chromosome 14. The proposita's partial duplication for the distal segment of 14q is apparently the result of crossing over within the inverted segment during meiosis. An attempt is made at assessing the risk that a carrier of the described pericentric inversion faces of having an abnormal child. The estimate of the risk depends on two factors: 1) the probability of a crossover occurring within the inverted segment during meiosis, and 2) the probability of a child with either of the two possible unbalanced recombinant chromosomes being born alive. An explanation is offered as to why some pericentric inversions confer a significant risk while others are so benign and occur with such a high frequency that they can be considered normal chromosomal variants, rather than chromosome aberrations.     

Two cases of interstitial deletion of the long arm of chromosome 1: del(1)(q21 → q25) and del(1)(q41 → q43)

Two unrelated children, one with a proximal interstitial deletion 1 (1(pter----q21: :q25----qter] and the other one with a distal interstitial deletion 1 (1(pter----q41: :q43----qter] are presented. The clinical features of the patient with a proximal deletion (q21-q25) correspond with those of eight earlier reported cases with a deletion 1q21/22/23----q25. The second patient with the distal interstitial deletion (q41-q43) is the first case published as far as we know. The clinical characteristics of the latter patient are compared with those of six cases with a terminal deletion 1q with at least one common band missing (1q42).     

Adjacent-2 disjunction of a maternal t(9;22) leading to duplication 9pter→q22 and deficiency of 22pter→q11.2

The proposita presented at birth with multiple congenital anomalies including craniofacial anomalies, bilateral cleft lip and palate, abnormalities of the urogenital system, talipes equinovarus, and the DiGeorge sequence. Cytogenetic investigation showed a 46,XX,- 22,+der(9)t(9;22)(q22;q11.2) karyotype. The mother, maternal uncle, and maternal grandmother of the infant are carriers of a reciprocal balanced translocation involving chromosomes 9 and 22 at regions q22 and q11.2, respectively. The unbalanced karyotype seen in the proposita arose due to an adjacent-2 disjunction of the quadrivalent in the mother. Prenatal diagnosis of the second pregnancy of this woman showed a similar karyotype. Review of the literature shows that adjacent-2 disjunction may occur preferentially when certain chromosomes are involved in translocations.     

Brief cytogenetic case report: A 4.5-year-old girl with deletion 4q syndrome — de novo, 46,XX,del(4) (pter→q31:)

A 3.5-year-old white girl had growth and mental retardation of prenatal origin, unusual facial appearance, cleft palate, abnormal sternum, absence or hypoplasia of some digits, diaphragmatic hernia, ventricular septal defect, and rib and vertebral anomalies. Her karyotype was 46,XX,del(4)(pter→q31:).     

Interstitial deletion of the long arm of chromosome 4, del(4)(q28→q31.3)

Interstitial deletions of the long arm of chromosome 4 are rare. Different breakpoints are involved. Only one of the patients had a very similar deletion to that of the present case. Both had low birth weight at term; weight, length and head circumference less than the third centile; epicanthic folds; apparently low-set abnormal ears; broad nasal bridge; micrognathia; hypoplastic nails; delayed psychomotor development; and mild mental retardation. © 1995 Wiley-Liss, Inc.