Intrachromosomal triplication of 15q11-q13

A 7 year old girl with intrachromosomal triplication 46,XX,-15,+der(15)(pter-->q13::q13-->q11::q11-->qter) resulting in tetrasomy of 15q11-q13 is reported. Fluorescence in situ hybridisation confirmed that the tetrasomic region included the entire segment normally deleted in Prader-Willi and Angelman syndrome patients, and breakpoints were similar to those reported in two tandem duplications of 15q11-q13. The middle repeat was inverted, suggesting a possible origin through an inverted duplication intermediate. Microsatellite analysis showed that the rearrangement was of maternal origin and involved both maternal homologues. Clinical findings included multiple minor anomalies (a fistula over the glabella, epicanthic folds, downward slanting palpebral fissures, ptosis of the upper lids, strabismus, a broad and bulbous tip of the nose, and small hands and feet), motor and mental retardation, a seizure disorder, and limited verbal abilities. In addition, immunological examination disclosed a selective immunodeficiency. The overall phenotype did not clearly resemble that of cases with tetrasomy 15pter-q13 associated with an extra inv dup(15)(pter-->q13:q13-->pter) chromosome. The latter aberration causes more severe mental deficit and intractable seizures, but less marked phenotypic alterations, although some overlap in mild facial dysmorphic features is present. A number of features common to Angelman syndrome were also observed in the patient.     

Prenatal diagnosis of de novo distal 5q duplication associated with hygroma colli, fetal oedema and complex cardiopathy

We report the first prenatal diagnosis of de novo distal 5q duplication after the echographic findings of hygroma colli and complex cardiopathy in a female fetus of 16 weeks' gestation. Cytogenetic studies on amniocytes showed a de novo inverted distal 5q duplication: karyotype: 46,XX, inv dup(5) (pter-->q3.53::q3.53-q3.33::q3.53-->qter). Based on the findings in the literature, a review of the malformative syndrome associated with partial distal 5q trisomy is given.     

A de novo interstitial deletion of chromosome 15 band q25 as revealed by FISH-technique

We report a new chromosomal finding in a 20 month-old girl. The minor clinical features included: moderate mental retardation, microcephaly, mild hypotonia and hypertelorism. Initially, what appeared to be a terminal deletion of the long arm of one chromosome 15 [15q26-->qter] was determined to be an interstitial deletion involving band 15q25 as revealed by FISH-technique, showing the presence of intact telomeric hybridization signals. The cytogenetic diagnosis was thus modified to 46,XX, del (15) (pter-->q24::q26--> qter). Nevertheless, the function of the enzyme telomerase should not be ignored, as healing could occur following such terminal deletions. Consequently, it will remain a difficult task to distinguish terminal deletions from those that are interstitial.     

Fusion of the MLL gene with two different genes, AF-6 and AF-5alpha, by a complex translocation involving chromosomes 5, 6, 8 and 11 in infant leukemia

We analysed a complex translocation involving chromosomes 5, 6, 8 and 11 in a case of infant leukemia. Molecular analysis of the MLL gene revealed that MLL was fused with two different genes, AF-6 on chromosome 6q27 and AF-5alpha. AF-5alpha, the 11th partner gene fused with MLL, is a novel gene mapped to chromosome 5q12, which encodes a 31 kDa protein of 269 amino acids and contains a possible nuclear targeting sequence, a potential leucine zipper dimerization motif and an alpha-helical coiled-coil domain. In situ hybridization and molecular cloning analyses demonstrated that two different types of chromosomal recombination had occurred in the cells. One was a three-way translocation among chromosomes 6, 8 and 11, and the other was an insertion of a chromosome 5-derived segment into the breakpoint of chromosomes 8 and 11. Accordingly, the karyotype was defined as del(5)(q11.2q12), der(6)t(6;8) (q27;q11.2), der(8)(8pter-->8q11.2::5q11.2-->5q12::11q23-->++ +11qter), der(11)t(6;11) (q27;q23). Thus, the MLL gene created two different fusion mRNAs, since the chromosome 11 split into two different chromosomes 5 and 6. This is the first report demonstrating fusion of the MLL gene with two different genes by a complex translocation.     

Characterization of Y3 receptor-mediated synaptic inhibition by chimeric neuropeptide Y-peptide YY peptides in the rat brainstem

Archival material from primary and metastatic renal clear cell carcinomas of 25 patients was studied by comparative genomic hybridization. Copy number changes of entire chromosomes or chromosomal subregions were detected in 22 primary and 21 metastatic tumors. Copy number changes affected the following chromosomes in at least 20% of the 25 primary tumors (minimal common region given in parentheses): gains were noted for chromosomes 1 (1q21-->q23), 5 (5q31-->q34), 7 (7p), 8 (8q), 16 (16p), 17 (17q12-->qter), 19, and 22 (22q12-->qter); losses were revealed for chromosomes 3 (3p21-->pter), 8 (8p23-->pter), 14(14q21-->qter), and Y. The same chromosomal regions that were involved in primary renal clear cell carcinomas were also found in the respective metastatic tumors but with strikingly different frequencies for a few regions. Metastatic tumors showed a significantly higher frequency of complete or partial gains of the long arm of chromosome 1, in particular at 1q21-->q23 than primary tumors (16 cases versus 6 cases; P < 0.005). These data suggest a correlation of metastatic events in renal clear cell carcinomas with an increase in the copy number of genes located at 1q, in particular at 1q21-->q23. In contrast, the entire or partial loss of the short arm of chromosome 3 was significantly less frequent in metastatic tumors (8 cases versus 15 cases; P < 0.025). The validity of 1q and 3p copy number changes detected by comparative genomic hybridization was confirmed by interphase cytogenetics with region-specific yeast artificial chromosomes to paraffin-embedded tumor tissue sections.     

Changes in pulmonary mechanics after fiberoptic bronchoalveolar lavage in mechanically ventilated patients

We describe perinatal findings in a female fetus with partial trisomy 8q(8q24.1-->8qter) and partial monosomy 15q(15q26.1-->15qter) resulting from a paternal t(8;15) reciprocal translocation. Prenatal sonographic examination showed intra-uterine growth retardation, bilateral ventriculomegaly, cardiomegaly with arrhythmia, anhydramnios, and absent kidney and urinary bladder images. The pregnancy was terminated at 28 weeks of gestation. At birth, the infant manifested typical dysmorphic features of partial trisomy 8q. Necropsy further revealed hydrocephalus, congenital diaphragmatic hernia, ventricular septal defect, a horseshoe kidney with renal hypoplasia, and kyphoscoliosis. Our case shows that the coexistence of partial trisomy 8q24.1-->8qter and partial monosomy 15q26.1-->15qter are more detrimental than either defect alone and can result in a complex of major malformations. Prenatal ultrasound examination and cytogenetic assessment should be offered in subsequent pregnancies.     

Mosaic tetrasomy 15q25-->qter in a newborn infant with multiple anomalies

We describe a premature boy with metopic craniosynostosis, facial anomalies, atrial-septal defect, hydronephrosis and flexion contractures of lower limbs, and mosaic tetrasomy 15q25-->qter. The extra chromosome material was present in the form of an acentric marker. A number of clinical manifestations observed in this child were also found in 3 previously reported patients who were trisomic for the same part of chromosome 15 and in 2 patients who were tetrasomic for a larger segment of 15q.     

Simultaneous operation of emergency coronary artery bypass grafting and gastrotomy with suturing ulcer

We report a 6 year old child with a small de novo interstitial deletion of proximal 4q, karyotype 46,XX,del(4)(pter-->q12::q13.1-->qter). She has made good developmental progress and attends normal school with minimal assistance. We review published reports and clinical findings in patients with proximal 4q deletions.     

Febrile episodes in children with cancer in the United Arab Emirates

We report the first patient with a partial trisomy and a partial monosomy of the long arm of chromosome 4: 46,XY, inv dup(4)(pter-->q32::q32-->q26), del(4)(q32-->qter). The boy died from a complex cardiac defect (monoventricle, monoatrium and truncus arteriosus) in combination with a diaphragmatic hernia. In addition he had preaxial polydactyly of the right hand. We compare the clinical features with data from the literature. The phenotype of the patient mainly resembles that in patients with a terminal deletion 4q32.     

A stable marker chromosome with a cryptic centromere: evidence for centromeric sequences associated with an inverted duplication

Centromere activation, an important mechanism in karyotype evolution, is occasionally observed in some human chromosome rearrangements. We report a possible occurrence of centromere activation in a marker chromosome containing an atypical centromere associated with an inverted duplication of the region 14q32 --> qter. The marker chromosome's reduced centromere lacks both the alpha and beta satellite sequences usually found at normal centromeres. In an attempt to identify the centromeric sequences, the marker chromosome was flow-sorted and amplified by a degenerate oligonucleotide primer polymerase chain reaction. Reverse chromosome painting experiments showed that the marker chromosome contains sequences that are unique to the distal region of chromosome 14, as well as a low copy number of (centromeric) sequences that are also highly represented in the centromeres of chromosomes 18 and 19. These data suggest the activation of a novel centromere in the 14q32 --> qter region, very likely consequent to the duplication of the region itself.     

Constitutional mosaicism for a chromosome 9 inversion resulting in recombinant aneusomy in an offspring

We report on a case of constitutional mosaicism for a large pericentric inversion of chromosome 9 in a man whose daughter had recombinant aneusomy resulting in partial 9q duplication and partial 9p deletion. At age 6 months, the girl was evaluated because of congenital anomalies [corrected] and developmental delay. Chromosomal analysis on this infant showed a derivative chromosome 9 which was later determined to be a recombinant chromosome with trisomy of 9q34.1-->qter and monosomy of pter-->9p24. Chromosomal analysis in her father showed the presence of two cell lines; 75% of lymphocytes had a 46,XY pattern, and 25% had a 46,XY,inv(9)(p24q34.1) karyotype. The infant's physical findings represent a composite of the reported cases of both trisomy 9q34.1-->qter and monosomy pter-->9p24. The infant's father was phenotypically and cognitively normal. This case broadens the spectrum of reported cases of mosaicism for an autosomal structural rearrangement generating unbalanced gametes, and further supports the tenet that constitutional mosaicism has clinical relevance for genetic counseling.     

Pediatric primary diffuse large cell lymphoma of bone with t(3;22)(q27;q11)

PURPOSE: A child with a primary lymphoma of bone (PLB) with a t(3;22)(q27;q11) is described. METHODS: An 11-year-old boy had a 5-week history of back pain and a destructive lesion of S1 that contained an epidural component. Histologic evaluation of a biopsy confirmed the diagnosis of diffuse large B-cell non-Hodgkin lymphoma. Karyotypic analysis disclosed a t(3;22)(q27;q11), but the amount of tumor tissue was insufficient for molecular studies of the BCL-6 gene. RESULTS: The patient remains free of disease 4 years after completion of intensive systemic chemotherapy and intrathecal chemotherapy. CONCLUSIONS: The lymphoma in the patient described in this report is highly unusual because of the coexistence of pediatric PLB and a t(3;22)(q27q11).     

Nucleotide sequence and genetic analysis of the leader region of Canadian, American and European equine arteritis virus isolates

We present the first report of chromosomal rearrangement involving chromosomes 4, 10 and 12. The proband was a 42-year-old woman with severe mental retardation and multiple congenital anomalies. The most striking physical anomalies were upper limb contractures resulting in distal arthrogryposis. As upper limb flexion contractures have been previously reported in individuals with partial distal 10q deletion, this sign should be considered as part of the clinical manifestations of 10q25-->qter monosomy.     

Chromosomes 22q11 deletion syndrome: an update and review for the primary pediatrician

Chromosome 22q11 deletion syndrome is a relatively newly described syndrome that encompasses the majority of patients previously felt to have velo-cardio-facial syndrome, DiGeorge syndrome, and conotruncal anomaly face syndrome. The disorder is characterized by a deletion of band 11 on the long arm of chromosome 22 most often recognized by fluorescent in situ hybridization (FISH) techniques. Extensive laboratory investigations are currently ongoing to uncover the specific genes involved and their functions. Phenotypically, individuals present with congenital heart disease, palatal abnormalities, facial dysmorphism, and developmental delay, as well as variable degrees of immunodeficiency, hypocalcemia, and endocrine abnormalities. The primary care physician has an important role in caring for these patients and their families. We review the current state of knowledge regarding chromosome 22q11 deletion syndrome, with an emphasis on the clinical presentation and on prevention and treatment of the known complications associated with this multisystem disorder. Chromosome 22q11 deletion syndrome can be inherited in an autosomal dominant fashion or result from a de novo deletion or translocation. Hence, this syndrome may have significant reproductive risks to affected individuals and families.     

Juvenile rheumatoid arthritis and del(22q11) syndrome: a non-random association

Del(22q11) is a common microdeletion syndrome with an extremely variable phenotype. Besides classical manifestations, such as velocardiofacial (Shprintzen) or DiGeorge syndromes, del(22q11) syndrome may be associated with unusual but probably causally related anomalies that expand its phenotype and complicate its recognition. We report here three children with the deletion and a chronic, erosive polyarthritis resembling idiopathic cases of juvenile rheumatoid arthritis (JRA). Patient 1, born in 1983, initially presented with developmental delay, facial dysmorphism, velopharyngeal insufficiency, and severe gastro-oesophageal reflux requiring G tube feeding. From the age of 3 years, he developed JRA, which resulted in severe restrictive joint disease, osteopenia, and platyspondyly. Patient 2, born in 1976, had tetralogy of Fallot and peripheral pulmonary artery stenosis. She developed slowly, had mild dysmorphic facial features, an abnormal voice, and borderline intelligence. JRA was diagnosed at the age of 5 years. The disorder followed a subacute course, with relatively mild inflammatory phenomena, but an extremely severe skeletal involvement with major osteopenia, restrictive joint disease (bilateral hip replacement), and almost complete osteolysis of the carpal and tarsal bones with phalangeal synostoses, leading to major motor impairment and confinement to a wheelchair. Patient 3, born in 1990, has VSD, right embryo-toxon, bifid uvula, and facial dysmorphism. She developed JRA at the age of 1 year. She is not mentally retarded but has major speech delay secondary to congenital deafness inherited from her mother. In the three patients, a del(22q11) was shown by FISH analysis. These observations, and five other recently published cases, indicate that a JRA-like syndrome is a component of the del(22q11) spectrum. The deletion may be overlooked in those children with severe, chronic inflammatory disorder.     

Predisposition for breast cancer in carriers of constitutional translocation 11q;22q

A translocation between the long arms of chromosomes 11 and 22, t(11;22)(q23;q11), is the most frequent constitutional reciprocal translocation in man. This chromosome abnormality has not previously been reported to be associated with an increased risk for neoplasia. The observation of one patient with a constitutional translocation t(11q;22q) and breast cancer prompted us to study the relationship between these two conditions. The incidence of breast cancer was determined in carriers of t(11q;22q). The karyotypes were determined by QFQ-banding, and the breakpoints were then further characterized by fluorescent in situ hybridization. Eight families with a total of 22 balanced carriers were found. In five of these families there was one case of breast cancer each. In another family a case of an unknown malignancy was reported in one member. No other malignancies were found among these patients. The number of breast cancer cases was significantly higher than expected among the translocation carriers (P < .001). The chromosomal breakpoints showed the same localization with the markers used, in the seven families studied. The association of constitutional translocation t(11q;22q) and breast cancer identifies a subset of patients with a highly increased risk for breast cancer who would benefit from counseling and screening. It also suggests the involvement of genes on 11q and/or 22q, in the tumorigenesis of breast cancer.     

Assignment of STK6 to human chromosome 20q13.2-->q13.3 and a pseudogene STK6P to 1q41-->q42

Fluorescence in situ hybridization analysis of human STK6 encoding a mitotic centrosomal protein kinase, Aik, revealed two signals in chromosome bands 20q13.2-->q13.3 and 1q41-->q42. Somatic cell hybrid panel analyses showed the existence of an identical sequence to STK6 cDNA on chromosome 20, and a processed pseudogene on chromosome 1. These results suggest that STK6 is localized at 20q 13.2-->q13.3 and a pseudogene STK6P at 1q41-->q42.