De novo partial trisomy 18p and partial monosomy 18q in a patient with anorectal malformation

Anorectal malformations (ARM) encompass a broad clinical spectrum which ranges from mild anal stenosis to severe anorectal anomalies such as complex cloacal malformations. The overall incidence of ARM is around 1 in every 2,500 live births. Although causative genes for a few syndromic forms have been identified, the molecular genetic background of most ARM remains unknown. The present report describes a patient with a de novo 13.2-Mb deletion of chromosome 18q22.3-qter and a 2.2-Mb de novo duplication of chromosomal region 18pter-p11.32 located at the telomeric end of chromosome 18q. The patient presented with ARM and the typical features of 18q- syndrome (De-Grouchy syndrome). The combination of a partial duplication of the short arm and a partial deletion of the long arm of chromosome 18 has been described in 16 previous cases. However, this is the first report of an association between this complex chromosomal rearrangement and ARM.     

Multiorgan autoimmunity in a Turner syndrome patient with partial monosomy 2q and trisomy 10p

Turner syndrome is a condition caused by numeric and structural abnormalities of the X chromosome, and is characterized by a series of clinical features, the most common being short stature and gonadal dysgenesis. An increased frequency of autoimmune diseases as well as an elevated incidence of autoantibodies has been observed in Turner patients.     

Distal trisomy 10q/partial monosomy 14q: an unusual clinical picture

A case of twin boy with partial trisomy for the distal part of the long arm of chromosome 10 (10q24-->qter) and a concomitant monosomy 14(q32-->qter) is reported. The chromosomal abnormalities resulted from a paternal balanced translocation involving chromosomes 10 and 14. An additional clinical feature was observed, viz. hypoplastic lungs. The proband's phenotype was compared to previously reported patients with partial trisomy 10q or 14q deletion.     

De novo partial 2q3 trisomy/distal 7p22 monosomy in a malformed newborn with 7p deletion phenotype and craniosynostosis

In the present paper a malformed male newborn is presented with de novo 2q3 trisomy/distal 7p22 monosomy and typical clinical findings of 7p deletion syndrome including trigonocephaly.     

Precocious puberty associated with partial trisomy 18q and monosomy 11q

We report a 10-years-old female patient with a partial trisomy 18q and monosomy 11q due to a maternal translocation. The phenotype of our proband is partially common with Jacobsen syndrome and duplication 18q but she has also some atypical anomalies such as precocious puberty, a retinal albinism and hypermetropia. Based on cytogenetics and FISH analysis, the karyotype of the proband was 46,XX,der(11)t(11;18)(q24;q13). To the best of our knowledge, this is the first report of precocious puberty associated with either dup(18q) or del(11q) syndromes.     

Two unrelated children with partial trisomy 1q and monosomy 6p,presenting with the phenotype of the Larsen syndrome

Summary Two unrelated children presented with similar clinical features (facial dysmorphism and multiple joint dislocations) suggesting the diagnosis of Larsen syndrome. Both carried an inherited unbalanced translocation resulting in partial trisomy 1q and partial monosomy 6p. Analysis of skin collagen from one of the probands disclosed a decreased 1/2 chain ratio of collagen type I, increased thermal stability and increased hydroxylation of proline and lysine. The present findings suggest that, as a result of the chromosome rearrangements, both patients have a mutation on a gene involved in collagen production, located either on chromosome 1q or, more probably, on 6p. It is furthermore suggested that other cases of Larsen syndrome are the result of a similar mutation.     

A patient with partial trisomy 21 and 7q deletion expresses mild Down syndrome phenotype

Backround

Down syndrome (DS) is the most common aneuploidy in live-born individuals and it is well recognized with various phenotypic expressions. Although an extra chromosome 21 is the genetic cause for DS, specific phenotypic features may result from the duplication of smaller regions of the chromosome and more studies need to define genotypic and phenotypic correlations.

Case report

We report on a 26 year old male with partial trisomy 21 presenting mild clinical symptoms relative to DS including borderline intellectual disability. In particular, the face and the presence of hypotonia and keratoconus were suggestive for the DS although the condition remained unnoticed until his adult age array comparative genomic hybridization (aCGH) revealed a 10.1 Mb duplication in 21q22.13q22.3 and a small deletion of 2.2 Mb on chromosomal band 7q36 arising from a paternal translocation t(7;21). The 21q duplication encompasses the gene DYRK1.

Conclusion

Our data support the evidence of specific regions on distal 21q whose duplication results in phenotypes recalling the typical DS face. Although the duplication region contains DYRK1, which has previously been implicated in the causation of DS, our patient has a borderline IQ confirming that their duplication is not sufficient to cause the full DS phenotype.     

Genotype/phenotype correlation in autosomal recessive lamellar ichthyosis.

Autosomal recessive lamellar ichthyosis is a severe congenital disorder of keratinization, characterized by variable erythema of the whole body surface and by different scaling patterns. Recently, mutations have been identified in patients with lamellar ichthyosis in the TGM1 gene coding for keratinocyte transglutaminase, and a second locus has been mapped to chromosome 2. We have now analyzed the genotype/phenotype correlation in a total of 14 families with lamellar ichthyosis. Linkage analyses using microsatellites in the region of the TGM1 gene confirmed genetic heterogeneity. In patients not linked to the TGM1 gene, the second region identified on chromosome 2 and a further candidate region on chromosome 20 were excluded, confirming as well the existence of at least three loci for lamellar ichthyosis. Sequence analyses of the TGM1 gene in families compatible with linkage to this locus revealed seven different missense mutations, five of these unpublished so far, and one splice mutation. No genotype/phenotype correlation for mutations in the TGM1 gene was found in this group of patients, which included two unrelated patients homozygous for the same mutation. Similarly, no clear difference in the clinical picture was seen between patients with TGM1 mutations and those unlinked to the TGM1 locus. Comparison of genetic and clinical classifications for patients with lamellar ichthyosis shows no consistency and thus indicates that clinical criteria currently in use cannot discriminate between the molecularly different forms of the disease.     

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.     

X monosomy and 21 trisomy in a sibship

Summary The case of a sibship of 4, 2 members of which present aneuploïdy (45,X and 47,XX,21+) is reported. The paternal grandfather and grandmother are first cousins and there is a large number of centromeric associations in the father.     

Partial monosomy 8p and partial trisomy 8p with moderate mental retardation.

A female patient with mosaicism for partial monosomy 8p and partial trisomy 8p is presented. Her karyotype is 46,XX, del(8)(p21)/46,XX, dup(8)(p21----pter). She showed minimal dysmorphic features, agenesis of the corpus callosum and moderate developmental delay. There is no previous report of mosaicism for partial monosomy and partial trisomy 8p. The clinical findings in the presently described patient are less severe than those reported in cases with only monosomy or trisomy of the distal part of chromosome 8.     

Genotype/phenotype correlation in a SCA1 family: anticipation without CAG expansion

We report on a family with spinocerebellar ataxia type 1 (SCA1), in which the age at onset and the severity of the disease do not correlate with the number of CAG repeat units. Although a marked anticipation was observed in the proband, it was not a consequence of an expansion of the CAG tract. None of the expanded alleles contained CAT interruptions. The pathologic expansion in this family was stable during the paternal but not maternal transmission, where it expanded by one trinucleotide and unexpectedly did not lead to anticipation. Our observations suggest that factors other than the length of the CAG repeat play a considerable role in determination of the disease course.     

Prenatal diagnosis of de novo partial trisomy 18p and partial monosomy 18q recurrent in a family with fatal aortic coarctation

Aortic coarctation is a life-threatening defect when it occurs with cardiorespiratory failure. Its genetic cause remains unknown. A woman was pregnant twice, both with male fetuses that had partial trisomy 18p, partial monosomy 18q, and aortic coarctation. The syndrome may relate to the aortic coarctation and pulmonary hypoplasia and is life-threatening. ArrayCGH analysis suggested a de novo 17.7 Mb deletion of chromosome 18q21.33 → qter (58,413,193 bp to 76,116,029 bp) and a de novo 12.4 Mb duplication of chromosome 18pter → p11.21 (1543 bp to 12,438,430 bp) at the telomeric end of chromosome 18. To the best of our knowledge, the present chromosomal breakpoint with rearrangement has not been previously described. This chromosome aberration may be responsible for this syndrome.     

Distal monosomy 16p13.3/distal trisomy 2p24.2-pter: molecular-cytogenetic characterisation and phenotype

We describe a 4-year-old boy with various facial dysmorphic features such as downslanting palpebral fissures, ptosis, hypertelorism, broad nasal bridge, small and low-set ears, broad philtrum, and micrognathia. In addition, profound mental retardation, myopia, muscular hypotonia as well as genital and cardiovascular abnormalities are also present. Refinement of the breakpoints by cytogenetic techniques, in particular the increase of banding resolution in conventional cytogenetic analysis, has enabled the correct diagnosis, as proven by fluorescence in situ hybridisation (FISH) using whole chromosome painting and single copy probes. We were able to demonstrate an unbalanced translocation that the patient inherited from his father resulting in a submicroscopic monosomy 16p13.3 and a trisomy 2p24.2-pter.     

X monosomy and 21 trisomy in a sibship.

The case of a sibship of 4, 2 members of which present aneuplo?dy (45,X and 47,XX,21+) is reported. The paternal grandfather and grandmother are first cousins and there is a large number of centromeric associations in the father.     

Partial trisomy 18q in a newborn with typical 18 trisomy phenotype

Summary This paper describes a case of partial trisomy of almost the entire long arm of chromosome 18 in a newborn with classic trisomy-18 phenotype, resulting from a de novo unbalanced 18q/21p translocation: karyotype: 46,XX,-21,t(18;21)(18qter18q11::21p1221qter). A review of the other reported cases of partial trisomy 18 suggests that a critical segment in chromosome 18, corresponding to bands q11-q12, might be responsible for most of the signs of trisomy 18, including failure to thrive and early death.     

Clinical and molecular cytogenetic analysis of a rare case of mosaicism for partial monosomy 3p and partial trisomy 10q in human

The results of comprehensive clinical examination and molecular cytogenetic analysis of a patient carrying chromosome 3p+ in 69% of the peripheral blood lymphocytes are presented. Using microdissection of the metaphase chromosomes followed by DOP-PCR, a DNA library specific for the abnormal chromosome was obtained. By fluorescence in situ hybridization (FISH) of this DNA library with chromosomes from the patient and a healthy donor, the aberrant chromosome was identified as der(3)t(3;10)(3p25;q24.3). Since this chromosome was present in only a proportion of patient's cells studied and no chromosome aberrations were revealed in cells of his parents, the der(3)t(3;10) is suggested to appear de novo. The cells carrying der(3)t(3;10) are monosomic for a proportion of 3p25 and trisomic for 10q24.3-->qter. The developmental malformations revealed in the patient, such as the specific features of facial skeleton, mental retardation, microcephaly, and others are similar to those described previously in patients with partial 3p monosomy and 10q trisomy.     

Partial trisomy 10p12.33 and partial monosomy 13q32.1: case report and a literature review

We report on a preterm neonate with a deletion of the distal long arm of chromosome 13q32.1 and partial trisomy of the short arm of chromosome 10p12.33. The patient has intrauterine growth retardation, microphthalmia, macrocephaly, holoprosencephaly, patent ductus arteriosus, aortic isthmus hypoplasia, right renal agenesis, imperforate anus, ambiguous genitalia, pleural effusion and vertebral anomaly. Analysis using an oligonucleotide microarray (U-array Cyto6000 array platform (Human Genome build: hg 18) indicated that there was a partial trisomy of chromosome 10(19.5 Mb gain) involving 298 oligonucleotides from 10pter to 10p12.33, and a partial monosomy of chromosome 13(18.3 Mb deleted) involving 313 oligonucleotides from 13q32.1 to 13qter. This is the first report of a patient with partial trisomy 10p12.33 and partial monosomy 13q32.1.