A de novo case of trisomy 10p: gene dosage studies of hexokinase, inorganic pyrophosphatase and adenosine kinase

Goyal-Naqvi Syndrome (Concurrent Trisomy 10p and Terminal 14q Deletion): A Review of the Literature

Goyal-Naqvi syndrome (GNS) is a newly documented clinical entity that comprises trisomy 10p and terminal 14q deletion, though trisomy 10p and terminal 14q deletion have been discovered as distinct conditions in 1974 and 1997, respectively. Nevertheless, to date, the total number of reported cases of each of these conditions is estimated to be in double digits. Both manifest as a constellation of features like craniofacial dysmorphism, hypotonia, intellectual impairment and global developmental delay. Characteristic facies include protruded forehead, hypertelorism, epicanthic folds, down slanting palpebral fissures, flat nasal bridge, long philtrum, thin upper lip, carp-shaped mouth, retro-micrognathia and low set ears. Besides, trisomy 10p is strikingly associated with clinodactyly and camptodactyly which aids in clinical diagnosis, apart from other musculoskeletal deformities like hip dysplasia and pes planus. Intersex conditions have been found to commonly co-exist. As other systems also display involvement frequently, trisomy 10p is a discernible multiple congenital anomalies/mental retardation (MCA/MR) syndrome. On the other hand, with terminal 14q deletion, increased risk of certain types of cancer was predicted as specific tumor suppressor genes are lost in the deletion and thus, screening was recommended. Genetic workup using techniques like fluorescence in situ hybridization (FISH), spectral karyotyping (SKY) and chromosomal microarray-based comparative genomic hybridization (CGH) was found to be helpful in diagnosis of trisomy 10p and 14q deletion. Prenatal diagnosis of these conditions has been well documented too. Intrauterine growth retardation has been observed to be related to trisomy 10p. There is a paucity of literature on the management of children diagnosed with trisomy 10p or with terminal 14q deletion. Although management of a child diagnosed with concomitant occurrence of trisomy 10p and terminal 14q deletion by a multidisciplinary approach emphasizing physiotherapeutic intervention has shown remarkable improvement in motor skills, the care of children diagnosed with these genetic aberrations needs further investigation. Documentation of more such cases will help to expand phenotypic spectrum for early identification and to delineate natural history for a life span approach. Early identification and intervention facilitate tapping of the maximum neuroplastic potential for better neurodevelopmental outcomes. We present a review of current literature on this novel syndrome to identify gaps in knowledge to build future research.

Small supernumerary marker chromosome originating from chromosome 10 associated with an apparently normal phenotype

Small supernumerary marker chromosomes (sSMC) originating from chromosome 10 are rare. Only seven cases have been documented, and among those three cases were diagnosed prenatally. We reported on another prenatal diagnosis of a de novo mosaic sSMC in an apparently normal female fetus whose mother had conceived with assisted reproductive technology (ART) procedures. G-banding analysis of amniotic cells was performed. Spectral karyotyping (SKY) and fluorescence in situ hybridization (FISH) studies with chromosome 10-specific alphoid satellite DNA probe were used to identify the chromosome 10 origin of the sSMC. Further FISH study with telomeric sequence probes showed that the sSMC lacked a hybridization signal, suggesting that the marker could be a ring chromosome. FISH studies using BAC clone probes specific for the regions within 10p11.2, 10q11.1, and 10q11.2 showed that the short arm breakpoint was located between 29.8 and 30.7 Mb from the 10p telomere, and that the long arm breakpoint was located less than 43.6 Mb from the 10p telomere. The karyotype of the fetus was 47,XX,+mar. ish der(10)(SKY+ CEP 10+, CTD-2130I7+, RP11-89J23-)/46,XX. Oligonucleotide microarray-based copy number variations (CNV) analysis was also performed and showed a 6.7 Mb duplication from 10p11.2 to 10q11.2 (36.2-42.9 Mb) with Affymetrix SNP-array 6.0 genotype: arr cgh. 10p11.2q11.2(CN_519687 --> CN_541524) X 3. At the 1-year follow-up, the baby did not have any findings of the trisomy 10p syndrome. This observation provided further credence to the concept that additional chromosome material of proximal 10p11.2 may not contribute to the trisomy 10p syndrome phenotype.

A de novo subterminal trisomy 10p and monosomy 18q in a girl with MCA/MR: case report and review

We report on a 3-year-old girl with psychomotor retardation, cardiopathy, strabismus, umbilical hernia, and facial dysmorphism in whom a de novo unbalanced submicroscopic translocation (10p;18q) was found by MLPA (Multiplex Ligation dependent Probe Amplification) and FISH analyses. Additional FISH studies with locus specific RP11 BAC probes and analyses with microsatellites revealed that the translocation resulted in a deletion estimated between 6 and 9 Mb on the maternal chromosome 18 and a subtelomeric 10p duplication of approximately 6.9 Mb. The proband's karyotype is 46,XX.ish der(18) t(10;18)(18pter-->18q23:10p15 --> 10pter). A subterminal duplication of 10p, as well as a subterminal deletion of 18q have been rarely reported so far. The clinical phenotype of this patient is reviewed and discussed.

Identification of de novo chromosome rearrangements: five cases analyzed with differential chromosome painting

We report on five cases of de novo structural chromosome rearrangements that were difficult to identify by conventional G-banding analysis. In all five cases, differential chromosome painting (DCP) provided evidence for the presence of an additional segment and its origin. A combination of DCP with subsequent conventional fluorescence in situ hybridization (FISH) analysis using adequate locus-specific probes and reexamination of G-banding patterns resulted in successful identification of the rearrangements. Their karyotypes were finally interpreted as 46,XY,der(1)(qter --> q42.1::p36.3 --> qter) in case 1; 46,XY,der(8)(8pter -->8q24.3::8q24.3 --> 8q23.2::?p11.2 --> ?ps) in case 2; 47,XY,+der(10)(pter --> q11) in case 3; 46,XX,der(3)(17pter --> 17p11.2::3p26 --> 3qter) in case 4; and 46,XY,dup(1) (pter --> q32::q25 --> qter) in case 5.

Pure trisomy 10p resulting from an extra ring chromosome: characterization by methods of advanced molecular cytogenetics

With the use of advanced molecular cytogenetic techniques, we have identified an extra ring chromosome consisting of the entire short arm of chromosome 10 (10p) in a 9-month-old girl with multiple congenital anomalies. This case represents another cytogenetic mechanism leading to the formation of pure complete trisomy 10p, which has not been reported previously. Pure trisomy 10p is rare. This case will further delineate those features associated with trisomy 10p.

Molecular cytogenetics, RFLP analysis and clinical characterization of a de novo trisomy 10p case

A new case of a de novo trisomy 10cen-->10pter is described. The karyotype was exactly defined by high resolution banding and FISH analysis; the chromosome aberration was of maternal meiotic origin as demonstrated by RFLP analysis. Clinical data are reported and correlated with other trisomy 10p cases from the literature. A critical review of the literature was made to define the phenotype of trisomy 10p syndrome.

Cloning and expression profile of human inorganic pyrophosphatase

We have cloned a 1.23 kb cDNA from a human heart library which encodes a 32 kDa protein that is 94% identical to bovine inorganic pyrophosphatase. The protein contains an aspartate-rich signature sequence that was previously identified in yeast and prokaryotic pyrophosphatases. Our clone detects a single band on Northern blots and is expressed at modest levels in all tissues examined. The cDNA shows linkage to markers on the long arm of chromosome 10.

Pure trisomy 10p involving an isochromosome 10p

We report a child with trisomy 10p due to a translocation of the long arm of chromosome 10 to the short arm of chromosome 14 and isochromosome formation of 10p [46,XX,i(10)(p10),der(14)t(10;14)(q10;p10)]. Most reported cases of trisomy 10p involve double segmental imbalance. In contrast, the clinical features described in the current case represent pure trisomy 10p and, thus, delineate the 10p trisomy syndrome phenotype. Mechanisms of the chromosomal rearrangements in this case are suggested.

Trisomy 10p: report of an unusual mechanism of formation and critical evaluation of the clinical phenotype

A de novo tandem inverted duplication of 10p was diagnosed in a 17-week fetus. The appearance of GTG banded preparations and the results of fluorescence in situ hybridization (FISH) studies are consistent with duplication of the entire arm, including the telomere. The FISH studies also demonstrated the presence of chromosome 10 alphoid repeats at the junction between the inverted segment and the long arm, consistent with the presence of the entire long arm of the abnormal chromosome. Therefore, this is a case of pure trisomy 10p without an associated deficiency of any other chromosome segment. A comparison of the phenotype associated with pure trisomy 10p and trisomy associated with a duplication/deficiency state documented a higher frequency (of borderline significance) of clubfoot and high-arched/cleft palate in the cases of pure trisomy. The frequency of palatal anomalies was observed to be significantly higher in the cases where the breakpoint of the trisomic segment is in the most proximal band (10p11). However, other clinical manifestations were observed inconsistently, even in the cases with pure, nearly complete trisomy 10p. Therefore, a clearly defined trisomy 10p clinical syndrome could not be documented in this study.

Further delineation of the partial proximal trisomy 10q syndrome

We report on a girl with a partial duplication of the proximal part of the long arm of chromosome 10, confirmed by chromosome painting. The phenotypic findings are compared to those found in six other published cases with the same karyotype. Recognition of a specific partial proximal trisomy 10q syndrome seems to be possible, consisting of mild to moderate developmental delay, postnatal growth retardation, microcephaly, prominent forehead, small and deep set eyes, epicanthus, upturned nose, bow shaped mouth, micrognathia, thick and flat helices of the ears, and long, slender limbs. Severe ocular malformations are possibly part of the syndrome. No major phenotypic differences were seen between patients with a duplication of segment 10q11-->10q22 and patients with a duplication of 10q21-->10q22.

10p duplication characterized by fluorescence in situ hybridization

We describe a patient with severe failure to thrive, mild-moderate developmental delay, cleft lip and palate, and other anomalies. Routine cytogenetic analysis documented a de novo chromosome rearrangement involving chromosome 4, but the origin of the derived material was unknown. Using chromosome specific painting probes, the karyotype was defined as 46,XY,der(4) t(4;10)(q35;p11.23). Characterization of the dup(10p) by fluorescence in situ hybridization (FISH) analysis provides another example of the usefulness of this technology in identifying small deletions, duplications, or supernumerary marker chromosomes.

Familial 10p trisomy resulting from a maternal pericentric inversion

We report a familial recombination of a pericentric inversion of chromosome 10 resulting in 2 affected relatives who had 10p trisomy and 10q monosomy with the karyotypic abnormality designated rec(10) dup p,inv(10) (p11.2q26). Both of these individuals had the typical characteristics of 10p trisomy, however, at birth the proposita had mild facial anomalies suggesting that the distinct facial characteristics may be of postnatal onset in some cases. In addition, the proposita had gastroesophageal reflux causing severe anemia. The phenotype of our patients is compared to 41 patients with 10p trisomy reported in the literature.