Ring chromosome X in a child with manifestations of Kabuki syndrome

A female patient with the karyotype 45, X/46, X, r(X)(p11.2 q13) and severe developmental delay, prominent fingertip pads, long palpebral fissures, short stature, and history of hypotonia had a phenotype reminiscent of Kabuki syndrome. We hypothesized that overexpression of X chromosome-derived sequences might be associated with the Kabuki-like phenotype observed. The nature and parental origin of this small-ring X were ascertained using a combination of genotyping with microsatellite markers and quantitative Southern blotting. PCR-based genotyping demonstrated heterozygosity at X-linked loci SBMA (Xq11-q12) and DXS227 (Xq13.1). Hemizygosity was observed at several loci: DMD STR-49 (Xp21.2), DXS1003 (Xp 11.23), DXS988 (Xp 11.21), DXS101 (Xq21.3), FMR-1 (Xq27.3), and DXYS64 (Xq28). This ring X chromosome is paternally derived since only maternal alleles are inherited at three informative microsatellite loci. Results of FISH and RT-PCR experiments indicate that the XIST locus is missing in the ring X chromosome and not expressed. These data indicated a large deletion of the X chromosome consistent with a small-ring X chromosome with approximate breakpoints near p11.2 and q13. These results are comparable to the observation of others where an atypically severe phenotype has been associated with the presence of an r(X), or small mar(X). Am. J. Med. Genet. 70:37–42, 1997. © 1997 Wiley-Liss, Inc.     

Phenotype associated with ring 10 chromosome: Report of patient and review of literature

A 15-month-old infant's peripheral blood chromosome analysis showed the following defects: 46,XY,r(10)(p15.3q26.1) in 84 cells, 45,XY,?r(10) in 13 cells, and 47,XY,r(10),+r(10) in one cell. Clinical abnormalities included growth retardation, microcephaly, prominent nasal bridge, macular hypoplasia, persistent pulmonary hypertension, and posterior urethral valves with hydronephrosis. Comparison of the phenotype of five other patients with a ring chromosome 10 with the present case showed the following common manifestations: growth retardation, microcephaly, undescended testes, hydronephrosis, and, in males, posterior urethral valves. To date, this last anomaly has not been seen in patients with either a del(10p) or a del(10q) abnormality.     

Ring 21 chromosome: the mild end of the phenotypic spectrum

The case is reported of a child with the karyotype 46,XY,r(21), who presented with linear growth retardation but who appears, at age 2 years 8 months, to be developing normally mentally. There is a small number of reports of mildly affected cases of r(21), and of some with an apparently completely normal phenotype. We presume a structural and functional cytogenetic heterogeneity underlies the observed phenotypic heterogeneity in the ring 21 spectrum.     

Ring syndrome caused by ring chromosome 7 without loss of subtelomeric sequences

Ring chromosome 7 is an unusual chromosome anomaly. Here we describe a patient with ring chromosome 7 and we show that both subtelomeres are still present. The diagnosis agrees with 'ring syndrome'. This report helps to further delineate the clinical manifestations of 'ring syndrome' and to distinguish the phenotypic consequences of the presence of a ring chromosome 7 from the phenotypic consequences of terminal chromosome 7 submicroscopic deletions.     

Interstitial deletion 13q. Further delineation of the syndrome by clinical and high-resolution chromosome analysis of five patients

Five patients with interstitial deletion 13q are reported. High-resolution chromosome banding established the diagnosis in two cases and stated the exact breakpoints in three remaining cases. All parents had normal chromosomes. An unequal and so far unexplained sex ratio of previously published and present cases was found: M:F = 1:2.75. Moderate to severe growth retardation was prominent in all patients. The patients were followed with psychological tests and growth data for 3–10 years. Mild to moderate mental retardation was present. Considerable phenotypic similarities were found in two patients with del(13)(q21.33 q31.3) and one with del(13)(q14.3q22.3). Repeat ophthalmological examinations showed no evidence of retinoblastoma in a male with del(13)(ql3.1q21.1). In conclusion, the long-term study of five patients with interstitial deletion 13q, all evaluated with high-resolution banding, contributed to a more reliable mental and growth prognosis in such patients.     

Terminal deletion of the short arm of chromosome 3

Summary A boy with growth and mental retardation, flat occiput, high and broad forehead, blepharoptosis, narrow palpebral fissures, low set, malformed ears, short neck, anal atresia, deep sacral dimple is reported. High-resolution banding analysis showed terminal deletion of the short arm of chromosome 3 (46,XY,del(3)(p25.3)). Deletions of the short arm of chromosome 3 are relatively rare. The clinical features of the patient are compared with those of 19 previously reported cases.     

Trisomy 9q3 syndrome: a case report and review of the literature

A girl with partial trisomy 9q is reported. She was characterized by dolichomorphism, abnormalities of the digits, a cardiac defect and craniofacial dysmorphism. A high-resolution analysis revealed the karyotype to be: 46,XX,-3,+ der(3)t(3;9)(q29;q13) de novo. A phenotype-karyotype correlation study in 22 cases of partial trisomies 9q supported the delineation of a trisomy 9q3 syndrome. The smallest region of overlap was confined to 9q32.     

Ring chromosome 15: Report of a case in an infertile man

Analysis of the karyotype of a sterile 34-year-old man, with slight mental retardation and small stature, but without significant dysmorphism, showed the presence of a ring chromosome 15.     

Ring Y chromosome: cytogenetic and molecular characterization

A female patient with Turner syndrome and the karyotype mos45,X/46,X,r(Y)/46,XY is described. Physical mapping of the ring chromosome by Y-specific single-copy and moderately repeated DNA sequences as molecular probes showed that, in addition to the heterochromatic part of Yq, a considerable portion of the Yp has also been lost in the course of the rearrangement. Thus, molecular findings provide independent support that this structurally abnormal sex chromosome is a ring Y and agree with the generally accepted model of ring formation requiring breaks in both chromosome arms. Clinical consequences of Y chromosome mosaicism in patients with Turner syndrome are discussed.     

Ring chromosome 5 in two malformed boys with Cri du Chat syndrome

Two cases of Cri du Chat syndrome were found to have a ring chromosome 5 in almost all their cells. The lack of the No. 5 short arm p15 band in both cases sufficed to produce the well-known features.     

Terminal deletion of the long arm of chromosome 10: A new case with breakpoint in q25.3

Since the first patient with partial deletion of the long arm of chromosome 10 was described in 1978, another 23 cases have been reported, with the breakpoint ranging from 10q23.3–26.2. To contribute further to the delineation of the monosomy 10qter syndrome, we describe a female child who, at age 3 6/12 years, was diagnosed with a de novo deletion of the long arm of chromosome 10, with a breakpoint in 10q25.3. The phenotypic manifestations in this child are compatible with those of previously reported cases. However, in contrast to most other patients, we found a moderate expression of the syndrome, with no genitourinary or cardiac malformations and with only mild retardation. Based on our observations and those of others, we conclude that a typical craniofacial appearance and varying degrees of psychomotor retardation are always found in patients with 10q− syndrome. Am. J. Med. Genet. 77:60–62, 1998. © 1998 Wiley-Liss, Inc.     

Ring chromosome 4 in a child with mild dysmorphic signs

We report on an 8-year-old boy exhibiting microcephaly, clinodactyly and growth retardation. Chromosome analysis showed a ring chromosome 4 in 97% of the cells and a high number of hyperploid cells with various ring formations. The breakpoints are presumed to be close to or in the telomeric regions of both arms. The patients reported with ring chromosome 4 and breakpoints close to the telomeres of both arms showed unspecific, mild clinical findings with normal or retarded mental development. These signs are probably related to the continuous generation of aneuploid cells.     

Ring chromosome 5 associated with severe growth retardation as the sole major physical abnormality

We report on a case of ring chromosome 5 in a 36-month-old girl with severe growth retardation, clinodactyly, mild psychological abnormalities, and normal facial appearance. Endocrine tests showed partial growth hormone deficiency. Cytogenetic investigation failed to demonstrate any apparent microscopic deletion of either short or long arm of chromosome 5 as consequence of ring formation. In 12% of cells examined, the ring was either absent or present in multiple copies. Only 3 previous cases of ring chromosome 5 have been reported in association with short stature of prenatal onset and minor anomalies, without mental retardation. © 1994 Wiley-Liss, Inc.     

Ring chromosome 20 with loss of telomeric sequences detected by multicolour PRINS

Brandt CA, Kierkegaard O, Hindkjær J, Jensen PKA, Pedersen S. Ring chromosome 20 with loss of telomeric sequences detected by multicolour PRINS.
Clin Genet 1993: 44: 26–31. © Munksgaard, 1993
A ring chromosome 20 in a male infant with epileptic seizures, mental and somatic growth retardation, and behavioural disturbances is described. Conventional cytogenetics revealed the karyotype to be 46,XY,r(20)(pter→qter) and no signs of mosaicism were found. Fluorescence in situ hybridisation using the clone p20Z1 identified the ring to be derived from chromosome 20. By counting 111 metaphases, only 7% were found to be missing the ring. The absence of telomeric sequences in the ring chromosome was demonstrated by multicolour PRINS: a three-step PRimed IN Situ labelling technique, using unlabelled primers. A terminal deletion of both arms thus seems to be the cause of the ring formation in the proband. Bivariate flow-analysis of chromosomes verified a deletion of the ring chromosome. The clinical and cytogenetic findings are compared with previous cases. A specific ring 20 syndrome seems justified.     

Pericentric inversion of chromosome 2 in a patient with the empty follicle syndrome: case report

The empty follicle syndrome (EFS) is defined as a lack of retrieved oocytes from follicles, at the time of repeated aspiration and flushing, following ovulation induction. The actual mechanism responsible for the EFS is still unknown. The aim of this study was to offer more information regarding the possible connection of this syndrome with pericentric inversion of chromosome 2. We give a case report of a patient who had multiple failed IVF attempts, due to the absence of oocyte and granulosa cells in the follicular fluid, following oocyte retrieval in both stimulated and natural cycles. Chromosomal analysis showed the presence of a pericentric inversion of chromosome 2: 46,XX,inv(2)(p11q21) in the female partner karyotype, while the male partner had a normal karyotype. Our case showed possible genetic factor influence in the aetiology of EFS.     

13号环状染色体综合征的临床及其细胞遗传学研究

本文对一例罕见的１３号环状染色体综合征患儿家系进行了外周血淋巴细胞培养、ＧＴＧ、ＣＢＧ、Ａｇ－ＮＯＲ显带和高分辨Ｇ显带等细胞遗传学研究，证实患儿核型为４５，ＸＸ，－１３／４６，ＸＸ，ｒ（１３）／４６，ＸＸ，ｒ（１３；１３）／４７，ＸＸ，２ｒ（１３；１３）（ｐ１１．２；ｑ３４），为一新生的、由４种不同异常细胞系组成的嵌合体，并对其产生原因及其与临床症状间的关系进行了讨论。