Deficiency of coagulation factors VII and X associated with deletion of a chromosome 13 (q34). Evidence from two cases with 46,XY,t(13;Y)(q11;q34)

Summary Deficiency of coagulation factors VII and X was found in two patients (Erlangen and Nancy) who shared the same chromosomal aberration 46,XY,t(13;Y)(q11;q34) with probable loss of a terminal segment of 13q. Loci involved in synthesis or constitution of these factors may be located at 13 (q34).The paper is dedicated to Prof. Dr. G. Koch on the occasion of his 70th birthday     

The structural gene for human coagulation factor X is located on chromosome 13q34

The gene coding for coagulation factor X was studied in a family segregating chromosomal abnormalities involving chromosomes 13 and 6. An individual monosomic for 13q34 was deficient in levels of clotting factors VII and X, while her brother, who is trisomic for 13q34, had elevated levels. DNA dosage studies with a cloned human factor X gene demonstrated that the low levels of factor X expression in the individual with the chromosome 13q34 deletion were due to the absence of one copy of the factor X structural gene. This confirms the assignment of the human gene coding for factor X to 13q34.     

Two cases of terminal deletion of chromosome 13: clinical features, conventional and molecular cytogenetic analysis

We report the cases of two unrelated patients with psychomotor retardation and craniofacial abnormalities, in whom cytogenetic studies have revealed a terminal deletion of chromosome 13 confirmed by fluorescence in situ hybridization (FISH). This del(13)(q33.2) is the smallest terminal deletion of the 13q reported so far. Interestingly enough, the serum level of coagulation factors VII and X, whose genes are located in 13q34, were reduced in both patients. These cases illustrate the difficulties in identifying precisely chromosome deletions and demonstrate that FISH techniques allow to obtain a more precise correlation between clinical phenotype and cytogenetic abnormalities.     

Exclusion of human chromosome 13q34 as the site of the cystic fibrosis mutation.

We have studied a family in which both cystic fibrosis (CF) and an unbalanced translocation between chromosomes 6 and 13 are found. As CF occurs in the child who is effectively monosomic for the translocated part of the long arm of chromosome 13, it was suggested that the locus of the gene mutation causing CF is on chromosome 13q34. The gene for human coagulation factor X is located at 13q34, and we have found a restriction fragment length polymorphism (RFLP) that is revealed by a cloned cDNA coding for this protein. Linkage analysis in eight CF families shows no evidence of cosegregation between CF and the gene for factor X, strongly suggesting that the locus for the defect causing cystic fibrosis is not at 13q34.     

Comparative genomic hybridization reveals a partial de novo trisomy 6q23-qter in an infant with congenital malformations: delineation of the phenotype

We report the use of comparative genomic hybridization (CGH) to define the origin of a small extra segment (unidentifiable by classical cytogenetics) present in a de novo add(13)q34 chromosome that we found in the karyotype of a newly born boy with congenital heart defects, brain anomalies and dysmorphic signs. Initial investigation with fluorescence in situ hybridization (FISH) and a chromosome-13-specific library revealed that the excess material was not derived from chromosome 13. To uncover the origin of the unknown chromosome material, CGH was carried out on DNA isolated from blood lymphocytes of the patient. By using a conventional fluorescence microscope with no digital imaging devices, a single distinct region with gain of fluorescent intensity was observed on distal chromosome 6q. Confirmation of this finding by FISH with a chromosome-6-specific paint and a subtelomeric yeast artificial chromosome clone from 6q26-q27, in combination with the band morphology of the small extra chromosomal segment, allowed us to diagnose the additional material as being derived from chromosome 6q23-qter. FISH with a telomere 13q probe detected a terminal deletion of 13q34-qter on the derivative chromosome 13, indicating that the der(13) was a result of a translocation event. Genotyping of the hypervariable apolipoprotein (a) gene, which lies within 6q26-q27, showed that the additional chromosome 6 material was inherited from the mother. The karyotype of the proposita is therefore: 46,XY,-13,+der(13)t(6;13)(q23;q34) de novo (mat). Our results confirm the usefulness of CGH as an attractive alternative method for the characterization of constitutional small genetic imbalances and contribute to the delineation of the trisomy 6q23-qter phenotype. Received: 26 November 1996 / Revised: 2 January 1997     

Evidence that activities of coagulation factors VII and X are linked to chromosome 13 (q34)

In 7 patients with various anomalies of chromosome 13 coagulation, studies were performed. A 50% decrease of activities of factor VII and X were noted only in cases with deletion of 13 (q34) which supports the hypothesis that they are linked to this region.     

The phenotype in partial 13q trisomies,apropos of a familial (13;15)(q22;q26) translocation

Summary A 12 month-old male patient with a karyotype 46, XY,-15,+der(15),t(13;15)(q22;q26)pat is presented. His stillborn sib showed malformations compatible with the 13q deletion syndrome, probably due to a 46,XY, der(13) karyotype. Phenotypic analysis of 41 cases from the literature with partial distal 13q (D13q) trisomies indicate that the segment 13q22 qter in trisomy with or without another concomitant aneusomy is sufficient to produce the majority of the trisomy 13 syndrome features, some of which (cleft palate, increased HbF and projections in PMN) are present in different non-overlapping partial 13q trisomies. About 82% of the D13q trisomies are inherited, more frequently from the mother.     

Evidence for Three Novel QTLs for Adiposity on Chromosome 2 With Epistatic Interactions: The NHLBI Family Heart Study

We sought to identify quantitative trait loci (QTLs) by genome‐wide linkage analysis for BMI and waist circumference (WC) exploring various strategies to address heterogeneity including covariate adjustments and complex models based on epistatic components of variance. Because cholesterol‐lowering drugs and diabetes medications may affect adiposity and risk of coronary heart disease, we excluded subjects medicated for hypercholesterolemia and hyperglycemia. The evidence of linkage increased on 2p25 (BMI: lod = 1.59 vs. 2.43, WC: lod = 1.32 vs. 2.26). Because environmental and/or genetic components could mask the effect of a specific locus, we investigated further whether a QTL could influence adiposity independently of lipid pathway and dietary habits. Strong evidence of linkage on 2p25 (BMI: lod = 4.31; WC: lod = 4.23) was found using Willet's dietary factors and lipid profile together with age and sex in adjustment. It suggests that lipid profile and dietary habits are confounding factors for detecting a 2p25 QTL for adiposity. Because evidence of linkage has been previously detected for BMI on 7q34 and 13q14 in National Heart, Lung, and Blood Institute Family Heart Study (NHLBI FHS), and for diabetes on 15q13, we investigated epistasis between chromosome 2 and these loci. Significant epistatic interactions were found between QTLs 2p25 and 7q34, 2q37 and 7q34, 2q31 and 13q14, and 2q31–q36 and 15q13. These results suggest multiple pathways and factors involving genetic and environmental effects influencing adiposity. By taking some of these known factors into account, we clarified our linkage evidence of a QTL on 2p25 influencing BMI and WC. The 2p25, 2q24–q31, and 2q36–q37 showed evidence of epistatic interaction with 7q34, 13q14, and 15q13.     

Regional mapping of clotting factors VII and X to 13q34. Expression of factor VII through chromosome 8

Summary Blood clotting factors were investigated in a patient with trisomy 8 mosaicism, a patient with an r(13), and a patient with distal trisomy 13q. Results are compatible with the assignment of the structural genes of factors VII and X to 13q34 and the existence of a regulatory mechanism associated with chromosome 8 controlling the expression of factor VII alone.     

The gene coding for the α-chain of human propionyl-CoA carboxylase maps to chromosome band 13q32

Summary The human gene encoding the -polypeptide of propionyl-CoA carboxylase (PCC) has hitherto been localized to the distal half of the long arm of chromosome 13, segment 13q22q34. We studied the enzyme activities of mitochondrial carboxylases in cell cultures obtained from patients with different deletions of chromosome 13. By setting the PCC activity in normal diploid cell cultures (control group) at 100%, cell cultures with trisomy 13 showed 150% activity. In contrast, one of four patients with partial monosomy 13 had an enzyme activity of only 50%. Thus, by comparative deletion mapping, combined with studies of the gene-dosage effect, we have been able to assign the PCCA gene locus to chromosome band 13q32.     

Partial trisomy 13 due to maternal translocation t(2;13)]

The authors report an observation of partial trisomy 13p13 leads to qter and suggest a clinical map of chromosome 13. Increase of fetal hemoglobin seems to be controlled by region 1 of 13q. Bands q13 q14 and q21 seem to be responsible for inner organ malformations. Lastly, the distal segment q22 leads to qter is responsible for trigonocephaly and limb abnormalities.     

Syntenic assignment of dopamine tautomerase (DCT) to bovine chromosome 12

Heterologous primers were used to amplify an exon and intron-containing segment of the bovine homologue of the human dopachrome tautomerase gene. After confirmation of homo-logy by sequence analysis (exon sequence similarity greater than 90%), bovine-specific primers were developed for synteny mapping purposes. The dopachrome tautomerase gene was assigned to bovine chromosome 12 (BTA12) with 97% concordance to the coagulation factor 10 locus. Together with previous synteny mapping of bovine chromosome 12 genes, fms-related tyrosine kinase, esterase D and 5-hydroxytryptamine receptor 2, this assignment further indicates conservation between human chromosome 13q and bovine chromosome 12.     

Two cases of del(13q)-retinoblastoma and two cases of partial trisomy due to a familial insertion

A del(13)(q13q21.1) was found in a patient with bilateral retinoblastoma and mental retardation. The father was carrier of an ins(16;13)(q12.2;q13q21.1) which also was present in several other family members, and responsible for another case of del (13q)-retinoblastoma and two cases of trisomy for the inserted segment. This second del(13q) patient was also carrier of a balanced t(11;22).     

Comparative mapping of seven genes in mouse, rat and Chinese hamster chromosomes by fluorescence in situ hybridization

By fluorescence in situ hybridization (FISH) using mouse probes, we assigned homologues for cathepsin E (Ctse), protocadherin 10 (Pcdh10, alias OL-protocadherin, Ol-pc), protocadherin 13 (Pcdh13, alias protocadherin 2c, Pcdh2c), neuroglycan C (Cspg5) and myosin X (Myo10) genes to rat chromosomes (RNO) 13q13, 2q24-->q25, 18p12-->p11, 8q32.1 and 2q22.1-->q22.3, respectively. Similarly, homologues for mouse Ctse, Pcdh13, Cspg5 and Myo10 genes and homologues for rat Smad2 (Madh2) and Smad4 (Madh4) genes were assigned to Chinese hamster chromosomes (CGR) 5q28, 2q17, 4q26, 2p29-->p27, 2q112-->q113 and 2q112-->q113, respectively. The chromosome assignments of homologues of Ctse and Cspg5 reinforced well-known homologous relationships among mouse chromosome (MMU) 1, RNO 13 and CGR 5q, and among MMU 9, RNO 8 and CGR 4q, respectively. The chromosome locations of homologues for Madh2, Madh4 and Pcdh13 genes suggested that inversion events were involved in chromosomal rearrangements in the differentiation of MMU 18 and RNO 18, whereas most of MMU 18 is conserved as a continuous segment in CGR 2q. Furthermore, the mapping result of Myo10 and homologues suggested an orthologous segment of MMU 15, RNO 2 and CGR 2.     

Translocation t(11;14) and trisomy 11q13----qter in multiple myeloma

A 14q+ marker with extra material derived from chromosome 11 long arm, i.e. segment q13----qter, has been found in cells from a pleural effusion in a patient with highly malignant multiple myeloma. The segment 11q13----qter was trisomic because of the presence of both apparently normal homologous chromosomes 11.     

Three chromosomes' (7;9;22) rearrangement and the origin of the Philadelphia chromosome

Summary A woman with chronic myelocytic leukemia had the Philadelphia chromosome and a complex four-break—three-chromosome rearrangement. The q32q34 portion of chromosome 9 is translocated to band q22 of chromosome 7, and at the end of this segment is attached the deleted q11 qter portion of chromosome 22. A review of 12 cases of the Philadelphia chromosome originating by the rearrangement of three or more chromosomes reveals that chromosomes 9 and 22 are always involved, while the third chromosome is a different one in each case. We discuss the hypothesis that the 22q segment is always specifically attached to band 9q34 wherever this portion of 9q is transposed.Address for offprint requests: Prof. M. Fraccaro, Gruppo Euratom, Via Forlanini, 14, I-27100 Pavia, Italy     

A 1.1 Mb deletion in distal 13q deletion syndrome region with congenital heart defect and postaxial polydactyly: Additional support for a CHD locus at distal 13q34 region

13q deletion syndrome is a rare genetic disorder, especially for group 3 deletion (13q33–q34 deletion). Previously we described a patient with congenital heart defect and mental retardation and proposed that a distal 6 Mb region might contain the causative gene of congenital heart defect. Here we present a new patient with congenital heart defects (CHD), hand and foot anomalies and mild mental retardation. We identified a 1.1 Mb deletion at chromosome 13q34 with high resolution SNP-array BeadChips (HumanOmni1-Quad, Illumina, USA). This chromosome region contains ten annotated genes, including GRK1, TFDP1, RASA3 and GAS6. To our knowledge, this represents the smallest 13q34 deletion identified to date. Our study provides additional support that distal 13q34 deletion region might contain key gene(s) responsible for cardiac development.     

A physical map of human chromosome 10 and a comparison with an existing genetic map.

A physical map for 13 loci on chromosome 10 was developed by determining the dosage of the corresponding DNA sequences in cell lines with unbalanced chromosome 10 rearrangements. Nine of the sequences were assigned to a smaller segment of the chromosome than previously and four sublocalizations were confirmed. The physical map covers most of chromosome 10, from 10p13 to 10q23. The linear order of loci within the physical map agrees with existing linkage maps of chromosome 10. A comparison between the physical map and existing genetic maps indicate an uneven distribution of recombination for chromosome 10. There appear to be hot spots of recombination in the regions defined by q21.1 and q22-q23. In addition, there is a suppression of recombination in the pericentromeric region in males which is not evident in females.     

Complex chromosomal rearrangement involving chromosomes 11, 13, 14 and 18 resulting in monosomy for 13q32----qter

A five-year-old boy with speech delay, minor facial abnormalities and borderline psychomotor retardation was found to have a complex de novo double translocation involving four chromosomes resulting in monosomy for the segment 13q32----qter. Chromosomes involved were 11, 13, 14, and 18. The translocation between chromosome 11 and 13 was unbalanced with the loss of the segment 13q32----qter. The second translocation between 14 and 18 was apparently balanced.     

YAC and cosmid FISH mapping of an unbalanced chromosomal translocation causing partial trisomy 21 and Down syndrome

Most cases of Down syndrome (DS) result from a supernumerary chromosome 21; however, there are rare cases in which DS is due to partial trisomy of chromosome 21, involving various segments of the chromosome. The characterization of cases of DS that are due to partial trisomy 21 allows the phenotype to be correlated with the genotype. We present a case with features of DS and a partial trisomy of chromosome 21 inherited from a paternal balanced translocation involving chromosomes 13 and 21. Fluorescence in situ hybridization analysis using yeast artificial chromosome (YAC) probes mapped the breakpoint to 21q22.1, within YAC 230E8, which contains markers CBR, D21S333 and D21S334. Further mapping using cosmids positioned the breakpoint proximal to CBR. The patient was also monosomic for the distal portion of chromosome 13 (q33–qter). Many phenotypic features of DS were present including hypotonia, flat occiput, flat facies, up-slanted palpebral fissures, epicanthic folds, flat nasal bridge, macroglossia, open mouth, small ears and a heart murmur. This case further supports the contention that the majority of the phenotypic features of DS map to 21q22–qter and further refines the location of some of them. In addition to the DS phenotype, the patient had a prominent upper maxilla with protruding upper incisors, and low levels of the coagulation factors VII and X, consistent with a syndrome resulting from monosomy 13q33–qter. Since some features overlap between the two syndromes, including severe mental retardation, it is unclear to what extent monosmy for 13q33–qter, trisomy for 21q22.1–qter, or a combination of both, contributed to the common features of the phenotype. Received: 27 March 1996 / Revised: 15 May 1996