Familial pericentric inversion of chromosome 13 resulting in duplication 13q22 to qter

Identification of partial trisomy 13q in two unrelated patients using single-nucleotide polymorphism array and literature overview

Background

Partial trisomy 13q is a less common chromosomal abnormality with a great clinical variability, among them, isolated partial trisomy 13q is extremely rare. Here, we report two new unrelated cases of partial trisomy 13q in Chinese families aiming to emphasize the genotype–phenotype correlation in partial trisomy 13q.

Methods

Enrolled in this study were two unrelated cases of partial 13q trisomy from two families in Quanzhou region South China. Karyotpe and single-nucleotide polymorphism (SNP) array analysis were employed to identify chromosome abnormalities and copy number variants in the families.

Results

A 72.9-Mb duplication in 13q14.11q34 region was identified using SNP array analysis in Patient 1 with an intellectual disability, developmental delay, seizures, gastric perforation, and other congenital malformations from a family with paternal inv(13)(p12q14.1). SNP array detection in Patient 2 revealed a 92.4-Mb duplication in 13q12.11q34 region combined with an 8.4-Mb deletion in Xq27.3q28 region with intellectual disability, developmental delay, cleft palate, and duplication of the cervix and the vagina. No chromosomal abnormality was elicited from the parents of Patient 2.

Conclusions

In this study, we presented two new unrelated cases of partial trisomy 13q with variable features in Chinese population, which may enrich the spectrum of the phenotypes partial trisomy 13q and further confirm the genotype–phenotype correlation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13039-022-00608-y.

Characterization of a familial balanced rec(13) in a child with mild MR and his half-sibling with two structurally rearranged chromosomes 13

In this report, we describe a 7-year-old child with mild mental retardation, developmental delay, and learning disabilities. His karyotype contained a rearrangement of chromosome 13, which appeared to include a duplication of 13q31-qter and a deletion of 13p12-pter regions. The chromosomal origin of the additional material was confirmed by fluorescence in situ hybridization (FISH) using a whole chromosome painting probe specific for chromosome 13. Family studies showed that his mother carried a balanced inversion of chromosome 13 and that his half-brother carried the balanced pericentric inversion of chromosome 13 from his mother as well as another structural rearrangement involving chromosome 13 presumably from his father. The findings from this study suggested that the proband's abnormal 13 resulted from an unbalanced crossing-over between the normal and maternal inverted chromosome 13.

Case report of rec(7)dup(7q)inv(7)(p22q22) and a review of the recombinants resulting from parental pericentric inversions on any chromosomes

We report a rare case of duplication for 7q22 --> 7qter and deletion for 7p22 --> 7pter, resulting from a meiotic recombination of a paternal pericentric inversion, inv(7)(p22q22). The newborn boy had the 7q trisomy syndrome. In addition, the diagnosis of chondrodysplasia punctata was made from lumbar and hand X-ray films taken soon after birth. Only two cases of rec(7)dup(7q), both in a single family, have been reported previously. We review 133 offspring with recombinations resulting from pericentric inversions on any chromosomes reported between 1981 and 1995. Of the 133 cases, 110 had a long-arm duplication and short-arm deletion, while only 23 had a short-arm duplication and long-arm deletion. In 85 of the 133 cases, the mother was an inversion carrier (five carriers had two affected offspring), and in 46, the carrier was a father (one carrier had three affected offspring). Kaiser [Hum Genet 1984;68:1-47] reviewed 63 offspring with recombinations derived from a parental pericentric inversion reported between 1972 and 1981. In both surveys, recombinations resulting from pericentric inversions of chromosomes 1, 12, 19, and Y were not found.

Elucidation of the centromere involvement in an inversion (13) by fluorescent in situ hybridisation

A newborn infant with phenotypic features of trisomy for distal 13q was found to have recombinant inversion duplication involving the (13)(q22-->qter) region. Parental karyotypes showed that the mother had a normal 46,XX complement and the father had an apparently balanced pericentric inversion of a chromosome 13. Because of the unusual nature of the inversion, the exact position of the centromere on the father's inverted chromosome 13 was difficult to assign by GTG banding, even on prometaphase chromosomes. CBG and NOR banding were not informative in determining the location of the centromere. Fluorescent in situ hybridisation with an alpha satellite DNA probe for D13Z1/D21Z1 helped in confirming the exact position of the centromere in the rearranged paternal chromosome. Thus, the origin of the proband's abnormal chromosome 13 was clarified.

Genetic risk for recombinant 8 syndrome and the transmission rate of balanced inversion 8 in the Hispanic population of the southwestern United States

A rec(8) dup(q) syndrome, secondary to a pericentric inversion--inv(8)(p23q22)--has been identified in 26 probands from Hispanic kindreds in the southwestern United States. The clinical phenotype of the Hispanic rec(8) syndrome includes a dysmorphic facies, cardiovascular and urinary-tract malformations, and mental retardation. Segregation analysis utilizing pedigree and cytogenetic data from 31 kindreds including five additional kindreds from additional sources has provided computation of genetic risks for counseling. An inv(8) carrier parent has a 6.2% risk of having a rec(8) child. The transmission rate of the inv(8) was significantly higher for inv(8) carrier mothers (59%) than for carrier fathers (42%). The combined transmission rate for both sexes was 53%. Risk for spontaneous abortion or stillbirth (11.3%) was not higher than the general population frequency of 13%-15%. It is significant that all kindreds identified to date are of Hispanic background with ancestors traced to the southern Colorado/northern New Mexico region. By means of extended pedigree information, three independently ascertained kindreds have been linked through common ancestry 4 generations in ascendance. The Hispanic background, geographic localization, and common ancestry in three kindreds suggest a single founder of the Hispanic inv(8) in the Southwest.

Segregation of inverted chromosome 13 in families ascertained through liveborn recombinant offspring

In humans pericentric inversions are rare structural chromosome abnormalities. Reproductive consequences of inversion heterozygosity depend upon many variables such as the chromosomes involved, the location of breakpoints, frequency of crossovers in the inverted segment, functional impairment of the gametes produced, and the viability of unbalanced zygotes that form. Therefore, each pericentric inversion may be studied as a unique mutation. This paper analyzes the segregation of inversion 13 chromosomes resulting from breaks at bands 13p12 and 13q21/22 in 11 apparently unrelated families. Ten of these families were ascertained through malformed fetuses or infants with a recombinant 13 duplication q, deletion p chromosome.

Phenotype-karyotype correlation in patients trisomic for various segments of chromosome 13

Analysis of clinical and cytogenetic findings taken from 62 published cases of partial trisomies of chromosome 13 showed that 15 had partial trisomy for the proximal long arm and 47 had trisomy for the distal long arm. Persistence of fetal haemoglobin (Hb F), increased projections of polymorphonuclear leucocytes (PMN), depressed nasal bridge, cleft lip/palate, and clinodactyly were more frequent in patients with proximal trisomy 13. In the distal trisomy group, the common features included haemangioma, bushy eyebrows, long curled eyelashes, prominent nasal bridge, long philtrum, thin upper lip, highly arched palate, and hexadactyly. In addition, several other features were common to both the groups, often showing inconsistency even when the same segment was in trisomy. The influence of the second aneusomy as the most likely cause for such inconsistent and overlapping phenotypes is discussed in view of the fact that 42 of 62 cases were derived from a balanced translocation carrier parent.

Congenital malformations and consanguinity

In this study in Bahrain increased maternal age, high parity, consanguinity and a history of 2 or more previous abortions were found to increase the risk of congenital malformation.

Trisomy 18 phenotype in a patient with an isopseudodicentric 18 chromosome

We report a female patient with a typical trisomy 18 phenotype who has a 46,XX, -18, +isopseudodic(18)(p11) karotype. The lack of features of the 18p- syndrome suggests that a significant amount of short arm material is present and that the Turner-like features associated with 18p- may be determined by monosomy for 18p11. The phenotype-genotype correlations in abnormalities affecting chromosome 18 are reviewed.

Familial pericentric inversion (13) detected by antenatal diagnosis

A recombinant rec (13), dup q chromosome was diagnosed in a 17-week fetus following amniocentesis. Subsequently, a familial pericentric inversion of chromosome 13 was seen to be segregating in the family and the same recombinant 13 was present in a mentally retarded aunt of the fetus. The clinical features of the carriers of the inversion product are discussed with reference to previous cases.