A case of monosomy 21

A new case of monosomy 21 was observed in a newborn male. Characteristic clinical features include: an antimongoloid eye slants, large and low set ears, flat nose bridge, hypoplastic nipples, cardiac anomalies, muscular hypotonia, retarded psychomotor development. The karyotypes of the parents were normal.     

Partial trisomy 8q and partial monosomy 18p: a case report

We report clinical observations and cytogenetic studies of an inherited partial trisomy 8q and partial monosomy 18p. A full trisomy 8 syndrome (Warkany syndrome) is a clinically recognized syndrome. Partial trisomy 8q has been reported sporadically in the literature with variable phenotypes. Partial monosomy 18p, deletion of the short arm of chromosome 18, is also a well-recognized syndrome. This is the first report to the best of our knowledge of partial trisomy for distal 8q and partial monosomy for distal 18p occurring together in a patient.     

Dissociation of tdic chromosomes: about a t(15;18)(p11;p11) leading to 18p monosomy

A 10-month-old girl with monosomy due to a de novo 45,XX,-15,-18,+tdic(15;18)(p11;p11) karyotype is described. The abnormal chromosome underwent dissociation into two telocentrics in 5/200 (2.5%) metaphases. This and other comparable instances indicate that, in addition to criss-cross separation of the dicentric chromatids, the characteristics of the anomalous reunion also influence the rate of dissociation. Besides, the mean maternal (31.2) and paternal (35.1) ages in this subtype of 18p monosomy are significantly increased.     

A case of (13q;18q) translocation with proximal 13q monosomy

Summary A case of partial monosomy of the 13p terminal to 13q12, associated with a de novo 13/18 translocation, is reported. The symptoms appeared to be derived from both 18q- and partial monosomy 13, the latter giving rise to: high arched palate, epicanthus, antimongolian slant, small eye fissure, flat nasal bridge, hypoplastic helix, and large clitoris. Serum Ig-A and Ig-M levels were normal in our case.     

Clinical case of tandem translocation between chromosomes 13 and 15

Cytogenetic and clinical examination of a patient (girl) with tandem translocation between chromosomes 13 and 15 was carried out. Translocation resulted in a partial loss of the genetic material between chromosomes 15 and 13. The problem on karyotype and phenotype relations with the loss of the respective chromosome regions is discussed.     

Presumptive monosomy 21 with neuronal migration disorder re-diagnosed as de novo unbalanced translocation t(18p;21q) by fluorescence in situ hybridisation

We present clinical and cytogenetic data of a one year old boy with partial monosomy for both 21q and 18p, resulting from a de novo unbalanced translocation. The initial diagnosis of a seemingly full monosomy 21 was revised after fluorescence in situ hybridisation (FISH) with whole chromosome painting probes and a locus-specific chromosome 21 probe. The karyotype was reinterpreted as 45,XY,der(18)t(18;21)(p11.2;q22.1),-21. This karyotype, to our knowledge, has not been previously described. The boy presented with a spectrum of clinical features previously described for (partial) monosomy 18p only, for monosomy 21q only, or for both of these aneusomies. The radiological finding of a neuronal migration disorder with localised polymicrogyria (cortical dysplasia) has not been described for either monosomy before.     

Partial monosomy 13 and 21 due to a familial 13/21 translocation

Summary Two patients are described with a monosomy for the proximal part of the long arm of chromosome 13 and for the distal part of the long arm of chromosome 21, due to an unbalanced 13/21 translocation.     

18q部分单体患儿的细胞和分子遗传学研究

临床发现1例智力低下伴轻度发育迟缓的女性患儿,对患儿进行G显带高分辨染色体核型分析, 发现18q21→qter缺失, 经多色荧光原位杂交和双色荧光原位杂交证实, 确定其核型为46,XX,del(18)(pter→q21:),ish del(18)(D18Z1+, qter-)。用DNA多态性方法分析, 该患儿从18q22.1至18qter区域内至少有8.7 Mbp丢失, 有MBP基因和GALNR基因缺失。缺失的18号染色体源自父亲。患者的智力低下和生长发育迟缓是18q21→qter缺失的结果, 或许与MBP基因和GALNR基因的缺失有关。     

Report of large kinship with familial translocation between chromosomes 21 and 22.

This paper reports a large kinship with a familial (21;22) translocation occurring in both the balanced and the unbalanced states. Recurrence risks for the (21;22) translocation in the unbalanced state are high (14%) for the offspring of female carriers as compared with those for the offspring of male carriers (4%), but the offspring of male carriers appear to have a much higher risk (50%) of being balanced carriers than those of female carriers (30%).     

Partial trisomy and monosomy 21 in an infant with an unusual de novo 21/21 translocation

A 3-month-old boy with a 46,XY,--21,+t(21;21)(pter leads to q22.3::q22.3 leads to q11::p11 leads to pter) karyotype, implicating trisomy for the 21q11 leads to 21q22.2 segment and monosomy for the 21q22.3 sub-band, is described. Most of the clinical features corresponded to Down syndrome ; other signs such as large ears, prominent nasal bridge and retromicrognathia were interpreted as the expression of 21q22.3 monosomy. The abnormal monocentric chromosome had satellites and stalks on both ends as a result of a 21q;21q translocation followed by deletion of one centromere region. Despite similar stalk size and NOR-Ag positiveness a significantly higher association frequency of the centrometric end as compared to the acentric end was found. This observation suggests that the satellite association phenomenon is not exclusively NOR-dependent, but that the centromeric and/or p11 regions of acrocentrics also play an important role.     

Miller-Dieker syndrome and monosomy 17p13:a new case

Summary A 12-year-old boy is described with multiple anomalies and a de novo terminal deletion of 17p13. Based on clinical examination, the Miller-Dieker syndrome was diagnosed.     

A female infant with monosomy 21

Summary A female infant with total monosomy 21 identified by Q banding is described. The main clinical features were hypertonia, prominent occiput, hypertelorism, antimongoloid slant of the eyes, broad nose, antimongoloid character of dermatoglyphics. Both parents are phenotypically as well as karyotypically normal.     

Partial trisomy 17q and monosomy 9p due to a familial translocation.

Described is an infant with partial trisomy 17q and monosomy 9p [46,XX,-9,+der(9)t(9;17)(p21;q23)] due to adjacent-1 segregation of a maternal balanced reciprocal translocation. Characteristic clinical features of both partial 17q trisomy and monosomy 9p are present, but the former syndrome is less recognisable in this infant than in previously reported cases due to the concomitant 9p monosomy.