ABSTRACT
A 22 year old woman with partial trisomy for the long arm of chromosome 2 is described. The karyotype is 46,XX, dir dup(2)(q33.1q35) de novo confirmed by FISH using a chromosome 2 specific paint. Parental chromosome studies were normal. To our knowledge this is the first report of trisomy for this specific segment of 2q and only the sixth case of de novo direct duplication of 2q, one of which was mosaic. Clinical features include epicanthus, clinodactyly, scoliosis, broad, flat nasal bridge, thin upper lip, long philtrum, and short neck.
Subject(s)
Abnormalities, Multiple/genetics , Chromosome Aberrations/genetics , Chromosomes, Human, Pair 2/ultrastructure , Intellectual Disability/genetics , Trisomy , Adult , Chromosome Disorders , Eyelids/abnormalities , Female , Humans , Nose/abnormalities , Scoliosis/geneticsABSTRACT
Bloom syndrome (BS) is an autosomal recessive disorder characterized by increases in the frequency of sister-chromatid exchange and in the incidence of malignancy. Chromosome-transfer studies have shown the BS locus to map to chromosome 15q. This report describes a subject with features of both BS and Prader-Willi syndrome (PWS). Molecular analysis showed maternal uniparental disomy for chromosome 15. Meiotic recombination between the two disomic chromosomes 15 has resulted in heterodisomy for proximal 15q and isodisomy for distal 15q. In this individual BS is probably due to homozygosity for a gene that is telomeric to D15S95 (15q25), rather than to genetic imprinting, the mechanism responsible for the development of PWS. This report represents the first application of disomy analysis to the regional localization of a disease gene. This strategy promises to be useful in the genetic mapping of other uncommon autosomal recessive conditions.
Subject(s)
Bloom Syndrome/genetics , Chromosome Aberrations , Chromosomes, Human, Pair 15 , Bloom Syndrome/diagnosis , Chromosome Mapping , Diagnosis, Differential , Humans , Infant, Newborn , Male , Mothers , Nondisjunction, Genetic , Polymorphism, Restriction Fragment Length , Prader-Willi Syndrome/diagnosis , Prader-Willi Syndrome/genetics , Repetitive Sequences, Nucleic Acid , Sister Chromatid Exchange , TelomereABSTRACT
An 18 month old girl with partial monosomy for the long arm of chromosome 22 is described. The karyotype was 46,XX,del(22)(pter----q13.1::q13.33----qter). To our knowledge this is the first report of monosomy for this specific segment of chromosome 22. Clinical features include developmental delay in all areas, hypotonia, macrosomia, full cheeks, eyebrows, and eyelids, mild epicanthus, wide nasal bridge, long philtrum, and thick lower lip. Parental chromosome studies were normal.
Subject(s)
Chromosome Aberrations/genetics , Chromosome Deletion , Chromosomes, Human, Pair 22 , Chromosome Banding , Chromosome Disorders , Female , Humans , InfantABSTRACT
Cytogenetic analysis of bone marrow cells from a 53-year-old man with acute nonlymphocytic leukemia (FAB-M4) revealed a t(2;14)(q23;q32.3) as the sole cytogenetic abnormality. This is the first report of a t(2;14)(q23;q32.3) as the sole abnormality in acute nonlymphocytic leukemia (M-4). The findings are discussed in relation to the possible role of genes located at 2q23 in acute nonlymphocytic leukemia.
Subject(s)
Chromosomes, Human, Pair 14 , Chromosomes, Human, Pair 2 , Leukemia, Myeloid, Acute/genetics , Translocation, Genetic , Humans , Male , Middle AgedABSTRACT
Three cases of partial trisomy 7q are described. One case had duplication of region 7q22.1----q31.2 owing to a de novo direct intra-arm intrachromosomal duplication. The other two cases, first cousins, were trisomic for 7q34----qter, resulting from recombination within the inserted segment of a dir ins(7;17)(q34;q23.1q25.3)mat. All three cases had a number of the already recorded manifestations of partial trisomy 7q, namely strabismus, low set ears, depressed nasal bridge, small nose, hypotonia, and mental retardation.
Subject(s)
Gene Rearrangement/genetics , Trisomy , Adult , Chromosome Banding , Chromosome Mapping , Chromosomes, Human, Pair 7 , Facial Bones/abnormalities , Female , Humans , Infant , Infant, Newborn , Karyotyping , Male , PedigreeABSTRACT
Trisomy for the distal part of the long arm of chromosome 8(q24.13----qter) is described in three sibs. The anomaly arose as an adjacent 1 meiotic segregation from a balanced reciprocal translocation t(1;8)(q44; q24.13)mat.
Subject(s)
Chromosomes, Human, Pair 8 , Trisomy , Adult , Child , Child, Preschool , Face/abnormalities , Female , Fingers/abnormalities , Humans , Infant, Newborn , Intellectual Disability/complications , Intellectual Disability/genetics , Male , Pedigree , Toes/abnormalitiesABSTRACT
We describe a 27 month old female child with partial monosomy for the short arm of chromosome 12: 46,XX,del(12)(p13.1----p13.3). She differs from the eight cases described by others, in that she is less severely affected. Her main clinical features are developmental delay, protruding tongue, strabismus, slightly unusual facies, slight micrognathia, and speech delay.
Subject(s)
Chromosome Deletion , Chromosomes, Human, Pair 12 , Developmental Disabilities/genetics , Child, Preschool , Chromosome Banding , Facial Expression , Female , Humans , Tongue HabitsABSTRACT
Three fragile sites 2q13, 12q13, and 17p12 were found in one family. In the index case, who was first investigated in 1969 for low birth weight and bilateral inguinal hernia, three tissues were examined, blood, marrow, and skin. Three of the family have been reinvestigated after 17 years. Cultures for sister chromatid exchange (SCE) and the effects of aphidicolin, fluorodeoxyuridine (FUdR), bromodeoxyuridine (BrdU), and methotrexate on the frequency of the fragilities were studied. The mother of the index case who is an obligate carrier for the fragile 2q13 does not express it in folate/thymidine deficient medium. Further studies on her using a lymphoblastoid cell line, showed that there was a reduced level of fragility of 12q13 and 17p12 in B-lymphocytes compared to T-lymphocytes. Excess thymidine and FUdR when added to the lymphoblastoid cell line did not induce the 2q13. These studies also confirm the induction of a range of common fragile sites by treatment with aphidicolin, showing in addition homozygosity for at least 3p14, 6q26, 16q23, and Xp22. There were no detectable increases in the SCE rate between individuals with fragile sites and the five controls tested. There was no history of cancer or phenotypic abnormalities in the family.
Subject(s)
Chromosome Fragility , Chromosomes, Human, 1-3 , Chromosomes, Human, 16-18 , Chromosomes, Human, 6-12 and X , Adolescent , Aphidicolin , Cells, Cultured , Chromosome Banding , Chromosome Fragile Sites , Diterpenes/pharmacology , Female , Folic Acid/pharmacology , Humans , Karyotyping , Male , Pedigree , Sister Chromatid Exchange/drug effectsABSTRACT
A 32-year-old mentally retarded woman was found to have a complex rearrangement of one chromosome 4. Her karyotype is interpreted as 46,XX,inv(4) (pter----p14::q12----p14::q12----qter) del (4) (pter----15.33::p15.2----qter). Clinically she does not show the features of the Wolf-Hirschhorn syndrome. Her phenotype and cytogenetic findings are compared with 2 other reported cases of 4p-without Wolf-Hirschhorn syndrome.
Subject(s)
Chromosomes, Human, 4-5 , Intellectual Disability/genetics , Adult , Chromosome Banding , Chromosome Deletion , Chromosome Inversion , Female , Humans , Karyotyping , Phenotype , SyndromeABSTRACT
We describe a woman with profound mental retardation and a direct duplication of 16q and fragile site fra(10)(q25). The identification and possible origin of the duplicated 16q is discussed along with the clinical manifestations. To our knowledge this is the first direct duplication of 16q to be reported. The karyotype is shown to be 46,XX, dir dup (16) (q11.2----q13).
Subject(s)
Chromosomes, Human, 16-18 , Chromosomes, Human, 6-12 and X , Intellectual Disability/genetics , Adult , Aneuploidy , Chromosome Fragile Sites , Chromosome Fragility , Female , HumansABSTRACT
A newborn male with partial trisomy for the distal part of the long arm of chromosome 14 (14q24 leads to qter) is described. The anomaly arose as an adjacent 1 meiotic segregation product from a balanced translocation t(11;14) (q25;q24) in the mother (figure). To our knowledge only one previous case involving the same segment has been reported. The karyotype was confirmed as 46,XY,der(11),t(11;14)(q25;q24) mat.
Subject(s)
Chromosomes, Human, 13-15 , Trisomy , Humans , Infant, Newborn , Male , Translocation, GeneticABSTRACT
Two cases of ring chromosome 11 are reported. Both had mental retardation, microcephaly, and short stature. High resolution G banding in case 1 showed no visible loss of chromatin, the karyotype being assessed as 46,XX,r(11) (p15 X 4q2 X 5). In case 2, a Wilm's tumour developed at 8 months and the child died at 18 months. Cytogenetic analysis by Q banding demonstrated minimal chromosome deletion and the karyotype was considered to be 46,XY,r(11) (p15q25).
Subject(s)
Chromosome Aberrations , Chromosomes, Human, 6-12 and X , Abnormalities, Multiple/genetics , Chromosome Banding , Female , Growth Disorders/genetics , Humans , Infant , Intellectual Disability/genetics , Kidney Neoplasms/genetics , Male , Microcephaly/genetics , Wilms Tumor/geneticsABSTRACT
We report a paracentric inversion of 1p in a boy with mild mental retardation. The chromosome aberration was identified by high resolution chromosome banding, and was also present in his phenotypically normal mother and other relatives. The boy's karyotype was considered to be 46,XY,inv(1) (p31,2p36.22) ISCN (1981).
