Distal trisomy 10q syndrome: phenotypic features in a child with inverted duplicated 10q25.1–q26.3

Prenatal diagnosis of Cri-du-Chat syndrome with concomitant distal trisomy 10q syndrome in one fetus with ultrasound anomalies

OBJECTIVE

The aim of this work was to characterize the genetic abnormalities and prenatal diagnosis indications in one fetus with Cri-du-Chat syndrome with codependent 10q24.2-q26.3 duplication in prenatal screening.

MATERIALS AND METHODS

A 31-year-old woman had a second trimester serum screening that indicated the fetus was at low risk. During this pregnancy, the woman underwent amniocentesis at 18⁺⁴ weeks' gestation because of adverse fertility history and nuchal fold thickening. Cytogenetic analysis and next-generation sequencing analysis were simultaneously performed to provide genetic analysis of fetal amniotic fluid. According to abnormal results, parental chromosome karyotype of peripheral blood was performed to analysis.

RESULTS

CNV-seq detected a 14.00 Mb deletion at 5p15.33-p15.2 and a 34.06 Mb duplication at 10q24.2-q26.3 in the fetus. Cytogenetic analysis of the fetus revealed a karyotype of 46, XY, der(5) t(5;10) (p15.2;q26.3). The karyotype of pregnant women was 46,XX,t(5;10) (p15.2;q24.2). The pregnancy was subsequently terminated after sufficient informed consent.

CONCLUSION

This is the first study that reports prenatal diagnosis of a Cri-du-Chat syndrome with concomitant 10 q24.2-q26.3 duplication. Adverse pregnancy history has to be as an important indicator for prenatal diagnosis, and the genetic factors of abnormal pregnancy should be identified before next pregnancy. Nuchal fold thickening is closely related to fetal abnormalities. Combined with ultrasonography, the use of CNV-seq will improve the diagnosis of submicroscopic chromosomal aberrations in fetuses with congenital anomalies.

Genetic Basis of Human Congenital Heart Disease

Congenital heart disease (CHD) is the most common major congenital anomaly with an incidence of ∼1% of live births and is a significant cause of birth defect-related mortality. The genetic mechanisms underlying the development of CHD are complex and remain incompletely understood. Known genetic causes include all classes of genetic variation including chromosomal aneuploidies, copy number variants, and rare and common single-nucleotide variants, which can be either de novo or inherited. Among patients with CHD, ∼8%-12% have a chromosomal abnormality or aneuploidy, between 3% and 25% have a copy number variation, and 3%-5% have a single-gene defect in an established CHD gene with higher likelihood of identifying a genetic cause in patients with nonisolated CHD. These genetic variants disrupt or alter genes that play an important role in normal cardiac development and in some cases have pleiotropic effects on other organs. This work reviews some of the most common genetic causes of CHD as well as what is currently known about the underlying mechanisms.

Neurodevelopmental Impairment As the Main Phenotypic Hallmark Associated with the Translocation t(7;10)(7p22.3;q26.11)

Reported here is a novel patient carrying an unbalanced t (10q26.11-q26.3; 7p22.3) and presenting with a severe intellectual disability with autistic features, abnormalities of muscle tone, and a drug-responsive epilepsy. The prominence of neurological and neurodevelopmental abnormalities in the clinical phenotype highlights a possible pathogenic role for different genes in the involved regions. Hypothetical mechanisms may include a possible gene dosage effect for DOCK1 and/or haploinsufficiency of PRKAR1B SUN1, ADAP1 , and GPER1 .

Familial 3-Way Balanced Translocation Causes 1q43→qter Loss and 10q25.2→qter Gain in a Severely Affected Male Toddler

Constitutional complex chromosomal rearrangements (CCRs) are rare events that typically involve 2 or more chromosomes with at least 3 breakpoints and can result in normal or abnormal phenotypes depending on whether they disturb the euchromatic neighborhood. Here, we report an unusual balanced CCR involving chromosomes 1, 9, and 10 that causes an unbalanced karyotype in a severely affected toddler. The CCR was initially reported as a maternal 2-way translocation but was reclassified as a 3-way translocation after a microarray analysis of the propositus revealed the involvement of another chromosome not identified by G-banding in his phenotypically normal mother. FISH assays on maternal metaphase cells confirmed that the 1qter region of der(1) was translocated to der(10), whereas the 10qter segment was translocated to der(9), which in turn donated a segment to der(1). Subsequently, this CCR was also identified in her phenotypically normal father (the patient's grandfather). Thus, the patient inherited the previously unreported pathogenic combination of der(1) with a loss of 1q43→qter (including AKT3, ZBTB18, HNRNPU, and SMYD3) and der(9) with a gain of 10q25.2→qter (including FGFR2), leading to a compound phenotype with key features of the 1q43→qter deletion and distal 10q trisomy syndromes. Our observations suggest that the loss of SMYD3 accounts for cardiac defects in a subset of patients. Moreover, due to recurrent miscarriages in this family, our findings allowed improved genetic counseling.

Clinical and molecular cytogenetic analyses of four patients with imbalanced translocations

Background

Chromosomal abnormalities that result in genomic imbalances are main causes of congenital and developmental anomalies including intellectual disability and multiple congenital malformations. In this report we describe four patients from three families with imbalanced translocations. Only a small percentage of imbalanced translocation individuals can be born to live, most of them were aborted in embryonic period. It is of great significances to precisely analysis the chromosome variation to study the relationship between genotype and phenotype.

Results

Four patients showed common clinical manifestations including delayed growth, intellectual disability, language barrier and facial dysmorphisms. In addition to the above features, lower limbs dysplasia and both foot eversion were found in patient 1, brachydactylic hand, cerebellar ataxia and congenital heart defects were also found in patient 4. Conventional karyotype analysis revealed abnormal karyotypes 46, XX, der (6) t (6: 10) (p23; q24), 46, XX, der (20) t (3; 20) (p23; p13) and 46, XX, der (22) t (3; 22) (q27; q13.3) in the four patients, respectively. Array-CGH analyses confirmed 23.6 Mb duplication on 10q25.1-q26.3 and 0.9 Mb deletions on 6p25.3, 19.9 Mb duplication on 3p24.3-p26.3 and 0.25 Mb deletion on 20p13 and 12.5 Mb duplication on 3q27.2-q29 and 1.9 Mb deletions on 22q13.2-q13.33 in the four patients, respectively.

Conclusion

Parents with balanced translocation are passed the imbalanced chromosome to patient, and the partial monosomy and partial trisomy lead to multiple congenital malformations of four patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s13039-016-0244-x) contains supplementary material, which is available to authorized users.

Relatives with opposite chromosome constitutions, rec(10)dup(10p)inv(10)(p15.1q26.12) and rec(10)dup(10q)inv(10)(p15.1q26.12), due to a familial pericentric inversion

Large pericentric inversions in chromosome 10 are rare chromosomal aberrations with only few cases of familial inheritance. Such chromosomal rearrangements may lead to production of unbalanced gametes. As a result of a recombination event in the inversion loop, 2 recombinants with duplicated and deficient chromosome segments, including the regions distal to the inversion, may be produced. We report on 2 relatives in a family with opposite terminal chromosomal rearrangements of chromosome 10, i.e. rec(10)dup(10p)inv(10) and rec(10)dup(10q)inv(10), due to familial pericentric inversion inv(10)(p15.1q26.12). Based on array-CGH results, we characterized the exact genomic regions involved and compared the clinical features of both patients with previous reports on similar pericentric inversions and regional differences within 10p and 10q. The fact that both products of recombination are viable indicates a potentially high recurrence risk of unbalanced offspring. This report of unbalanced rearrangements in chromosome 10 in 2 generations confirms the importance of screening for terminal imbalances in patients with idiopathic intellectual disability by molecular cytogenetic techniques such as FISH, MLPA or microarrays. It also underlines the necessity for FISH to define structural characteristics of such cryptic intrachromosomal rearrangements and the underlying cytogenetic mechanisms.

Distal trisomy 10q syndrome, report of a patient with duplicated q24.31 - qter, autism spectrum disorder and unusual features

Key Clinical Message

We report on a patient with distal trisomy 10q syndrome presenting with a few previously undescribed physical features, as well as, autism spectrum disorder (ASD). We recommend that patients with distal trisomy 10q syndrome should have a behavioral evaluation for ASD for the early institution of therapy.

Inverted Duplication and Deletion of 10q25q26 in a Patient without Any Obvious Skeletal Anomalies

We report on a girl with inverted duplication and deletion of 10q25q26 revealed by array-CGH and FISH analysis. Array-CGH analysis demonstrated a ∼13.1-Mb duplication encompassing 10q25.3q26.2 and a ∼5-Mb deletion at 10q26.2q26.3. No single-copy region was detected between the deleted and duplicated segments. FISH analysis found the arrangement duplicated in an inverted position. FISH analysis using the same probes did not show any abnormality in both parents, which indicates a de novo occurrence. The frequently reported features of distal 10q duplication include developmental delay, blepharophimosis, hypotonia, skeletal anomalies and some facial dysmorphisms. The girl presented with many features of distal 10q duplication with the exception of skeletal anomalies. To our knowledge, this is the fourth patient reported in the literature with inv dup del 10q. 10q duplication seems to account for most of the phenotypes for our patient. Although no obvious skeletal feature was found in our patient at present, follow-up assessment of skeletal development should be planned with the increase of age.

Dose dependent expression of HDAC4 causes variable expressivity in a novel inherited case of brachydactyly mental retardation syndrome

Histone deacetylase 4 (HDAC4) serves important roles in multiple human systems, including neurological, cardiac, and skeletal functions. Mutation or deletion of HDAC4 causes brachydactyly mental retardation syndrome (BDMR), a disorder that includes intellectual disability, behavioral abnormalities, autism spectrum disorder, and craniofacial and skeletal anomalies, including brachydactyly type E. We present a case of familial BDMR, including a parent with mild symptoms of the disorder and a child exhibiting a more severe phenotype. Cytogenetic testing showed a cryptic balanced translocation in the mother that resulted in a 2q37.1 monosomy and a 10q26.1 trisomy in the son. Gene expression analyses demonstrated 67% HDAC4 expression in the mother and 23% HDAC4 expression in the son relative to normal controls, lending evidence to the hypothesis that HDAC4 modulates severity of this disorder in a dosage-dependent manner.

Complex distal 10q rearrangement in a girl with mild intellectual disability: follow up of the patient and review of the literature of non-acrocentric satellited chromosomes

We report on an intellectually disabled girl with a de novo satellited chromosome 10 (10qs) and performed a review of the literature of the non-acrocentric satellited chromosomes (NASC). Satellites and stalks normally occur on the short arms of acrocentric chromosomes; however, the literature cites several reports of satellited non-acrocentric chromosomes, which presumably result from a translocation with an acrocentric chromosome. This is, to our knowledge, the third report of a 10qs chromosome. The phenotype observed in the proband prompted a search for a structural rearrangement of chromosome 10q. By microsatellite analysis we observed a 4 Mb deletion on the long arm of chromosome 10, approximately 145 kb from the telomere. FISH and array CGH analyses revealed a complex rearrangement involving in range from the centromere to the telomere: A 9.64 Mb 10q26.11-q26.2 duplication, a 1.3 Mb region with no copy number change, followed by a 5.62 Mb 10q26.2-q26.3 deletion and a translocation of satellite material. The homology between the repeat sequences at 10q subtelomere region and the sequences on the acrocentric short arms may explain the origin of the rearrangement and it is likely that the submicroscopic microdeletion and microduplication are responsible for the abnormal phenotype in our patient. The patient presented here, with a 15-year follow-up, manifests a distinct phenotype different from the 10q26 pure distal monosomy and trisomy syndromes.