Novel case of dup(3q) syndrome due to a de novo interstitial duplication 3q24-q26.31 with minimal overlap to the dup(3q) critical region

New insights on partial trisomy 3q syndrome: de novo 3q27.1-q29 duplication in a newborn with pre and postnatal overgrowth and assisted reproductive conception

BACKGROUND

Duplications of the long arm of chromosome 3 are rare, and associated to a well-defined contiguous gene syndrome known as partial trisomy 3q syndrome. It has been first described in 1966 by Falek et al., and since then around 100 patients have been reported. Clinical manifestations include characteristic facial dysmorphic features, microcephaly, hirsutism, congenital heart disease, genitourinary anomalies, hand and feet abnormalities, growth disturbances and intellectual disability. Most of cases are due to unbalanced translocations, inherited from a parent carrying a balanced aberration (reciprocal translocation or inversion), and rarely the genomic anomaly arises de novo. Very few studies report on the prenatal identification of such rearrangements.

CASE PRESENTATION

Hereby, we report on a newborn with a rare pure duplication of the long arm of chromosome 3. Noninvasive prenatal test (cell free fetal DNA analysis on maternal blood), performed for advanced parental age and use of assisted reproductive technique, evidenced a partial 3q trisomy. Then, invasive cytogenetic (standard and molecular) investigations, carried out through amniocentesis, confirmed and defined a 3q27.1-q29 duplication spanning 10.9 Mb, and including about 80 genes. Our patient showed clinical findings (typical facial dysmorphic features, esotropia, short neck, atrial septal defect, hepatomegaly, mild motor delay) compatible with partial trisomy 3q syndrome diagnosis, in addition to pre- and postnatal overgrowth.

CONCLUSIONS

Advanced parental age increases the probability of chromosomal and/or genomic anomalies, while ART that of epigenomic defects. Both conditions, thus, deserve more careful prenatal monitoring and screening/diagnostic investigations. Among the latter, cell free fetal DNA testing can detect large segmental aneuploidies, along with chromosomal abnormalities. It identified in our patient a wide 3q rearrangement, then confirmed and defined through invasive molecular cytogenetic analysis. Neonatologists and pediatricians must be aware of the potential risks associated to duplication syndromes. Therefore, they should offer to affected subjects an adequate management and early and careful follow-up. These may be able to guarantee to patients satisfactory growth and development profiles, prevent and/or limit neurodevelopmental disorders, and timely recognition of complications.

A Pure 2-Mb 3q26.2 Duplication Proximal to the Critical Region of 3q Duplication Syndrome

Partial duplication of chromosome 3q - dup(3q) - is a recognizable syndrome with dysmorphic facial features, microcephaly, digital anomalies, and genitourinary and cardiac defects, as well as growth retardation and developmental delay. Most cases of dup(3q) result from unbalanced translocations or inversions and are accompanied by additional chromosomal imbalances. Pure dup(3q) is rare, and only 31 cases have been reported so far. We report a new case of a girl with a pure 2-Mb duplication at 3q26.2 not encompassing the known critical region 3q26.3q27. After an extensive review, to the best of our knowledge, the case herein presented harbors the shortest 3q duplication of this region. The clinical phenotype of this patient resembles previously reported cases of pure dup(3q) syndrome, including intellectual disability, synophrys, a wide nasal bridge, dysmorphic ears, clinodactyly, and cardiac defects. We suggest that the 3q26.2 duplication is a candidate copy number alteration explaining our patient's clinical phenotype.

Familial intellectual disability as a result of a derivative chromosome 22 originating from a balanced translocation (3;22) in a four generation family

Background

Balanced reciprocal translocation is usually an exchange of two terminal segments from different chromosomes without phenotypic effect on the carrier while leading to increased risk of generating unbalanced gametes. Here we describe a four-generation family in Shandong province of China with at least three patients sharing severe intellectual disability and developmental delay resulting from a derivative chromosome 22 originating from a balanced translocation (3;22) involving chromosomes 3q28q29 and 22q13.3.

Methods

The proband and his relatives were detected by using karyotyping, chromosome microarray analysis, fluorescent in situ hybridization and real-time qPCR.

Results

The proband, a 17 month-old boy, presented with severe intellectual disability, developmental delay, specific facial features and special posture of hands. Pedigree analysis showed that there were at least three affected patients. The proband and other two living patients manifested similar phenotypes and were identified to have identically abnormal cytogenetic result with an unbalanced translocation of 9.0 Mb duplication at 3q28q29 and a 1.7Mb microdeletion at 22q13.3 by karyotyping and chromosome microarray analysis. His father and other five relatives had a balanced translocation of 3q and 22q. Fluorescence in situ hybridization and real-time qPCR definitely validated the results.

Conclusions

The abnormal phenotypes of the proband and his two living members in four generations of the family confirmed the 3q duplication and 22q13.3 deletion inherited from familial balanced translocation. This is the first report of familial balanced reciprocal translocation involving chromosomes 3q28q29 and 22q13.3 segregating through four generations.

Rare de novo inversion-duplication case with pure 3qter duplication syndrome including an overlap of the dup(3q) critical region: A case report

We report here a very rare case of de novo inversion-duplication chromosomal abnormality with a pure 3qter duplication syndrome. Interestingly, the 3q duplication includes an overlap of the syndromes critical region. Although there have only been 9 cases of this syndrome reported in the past, our patient had more severe neurological abnormalities than anticipated. In this regard, we have gathered the 3q chromosomal duplication abnormalities known to cause pure 3q duplication syndrome to date as a reference for comparisons and we discuss the particulars of our case.

Comprehensive review of the duplication 3q syndrome and report of a patient with Currarino syndrome and de novo duplication 3q26.32-q27.2

Partial duplications of the long arm of chromosome 3, dup(3q), are a rare but well-described condition, sharing features of Cornelia de Lange syndrome. Around two thirds of cases are derived from unbalanced translocations, whereas pure dup(3q) have rarely been reported. Here, we provide an extensive review of the literature on dup(3q). This search revealed several patients with caudal malformations and anomalies, suggesting that caudal malformations or anomalies represent an inherent phenotypic feature of dup(3q). In this context, we report a patient with a pure de novo duplication 3q26.32-q27.2. The patient had the clinical diagnosis of Currarino syndrome (CS) (characterized by the triad of sacral anomalies, anorectal malformations and a presacral mass) and additional features, frequently detected in patients with a dup(3q). Mutations within the MNX1 gene were found to be causative in CS but no MNX1 mutation could be detected in our patient. Our comprehensive search for candidate genes located in the critical region of the duplication 3q syndrome, 3q26.3-q27, revealed a so far neglected phenotypic overlap of dup(3q) and the Pierpont syndrome, associated with a mutation of the TBL1XR1 gene on 3q26.32.

A unique case of a discontinuous duplication 3q26.1-3q28 resulting from a segregation error of a maternal complex chromosomal rearrangement involving an insertion and an inversion

Until now, few cases of partial trisomy of 3q due to segregation error of parental balanced translocation and segregation of a duplicated deficient product resulting from parental pericentric inversion have been reported so far. Only five cases of chromosomal insertion malsegregation involving 3q region are available yet, thus making it relatively rare. In this case report, we are presenting a unique case of discontinuous partial trisomy of 3q26.1-q28 region which resulted from a segregation error of two insertions involving 3q26.1 to 3q27.3 and 3q28 regions with ~21Mb and ~2Mb sizes, respectively. The maternally inherited insertion was cytogenetically characterized as der(8)(8pter→8p22::3q26→3q27.3::3q28→3q28::8p22→8qter) and the patient's major clinical features involved Dandy Walker malformation, sub-aortic ventricular septal defect, upslanting palpebral fissures, clinodactyly, hirsutism, and prominent forehead. Besides, a review of the literature involving cases with similar chromosomal imbalances and cases with "3q-duplication syndrome" is also provided.

Clinical, Cytogenetic, and Biochemical Analyses of a Family with a t(3;13)(q26.2;p11.2): Further Delineation of 3q Duplication Syndrome

Chromosomal abnormalities that result in genomic imbalances are a major cause of congenital and developmental anomalies. Partial duplication of chromosome 3q syndrome is a well-described condition, and the phenotypic manifestations include a characteristic facies, microcephaly, hirsutism, synophrys, broad nasal bridge, congenital heart disease, genitourinary disorders, and mental retardation. Approximately 60%–75% of cases are derived from a balanced translocation. We describe a family with a pure typical partial trisomy 3q syndrome derived from a maternal balanced translocation t(3;13)(q26.2;p11.2). As the chromosomal rearrangement involves the short arm of an acrocentric chromosome, the phenotype corresponds to a pure trisomy 3q26.2-qter syndrome. There are 4 affected individuals and several carriers among three generations. The report of this family is relevant because there are few cases of pure duplication 3q syndrome reported, and the cases described here contribute to define the phenotype associated with the syndrome. Furthermore, we confirmed that the survival until adulthood is possible. This report also identified the presence of glycosaminoglycans in urine in this family, not related to the chromosomal abnormality or the phenotype.

3q26.31-q29 duplication and 9q34.3 microdeletion associated with omphalocele, ventricular septal defect, abnormal first-trimester maternal serum screening and increased nuchal translucency: prenatal diagnosis and aCGH characterization

We present prenatal diagnosis and array comparative genomic hybridization characterization of 3q26.31-q29 duplication and 9q34.3 microdeletion in a fetus with omphalocele, ventricular septal defect, increased nuchal translucency, abnormal first-trimester maternal screening and facial dysmorphism with distinct features of the 3q duplication syndrome and Kleefstra syndrome. The 26.61-Mb duplication of 3q26.31-q29 encompasses EPHB3, CLDN1 and CLDN16, and the 972-kb deletion of 9q34.3 encompasses EHMT1. We review the literature of partial trisomy 3q associated with omphalocele and discuss the genotype-phenotype correlation in this case.

A boy with partial trisomy of chromosome 3q24-q28 from paternal balanced insertion and multiple congenital anomalies

Although many patients with duplication 3q syndrome have been described reports on duplication derivatives from an insertion are rare in the previous literature. Here we describe the genotype and phenotype of a 32-month-old boy with a partial trisomy of 3q24-q28. We carefully mapped the aberration with SNP-array analysis, and found a duplication region of 44 Mb. By conventional cytogenetic techniques including fluorescence in situ hybridization (FISH) and spectral karyotyping (SKY) analysis, the patient was found to have inherited a derivative chromosome 6 from his father, which was contained a direct insertion from 3q24-28. The main clinical features of the patient included severe mental retardation, postnatal developmental delay, ventricular septal defect (VSD), and craniofacial anomalies including cleft palate, frontal bossing, hypertelorism, and a broad nasal bridge. The symptoms partially overlap with previously reported patients with duplication in the same region. Prenatal diagnosis for the fetus of this family was performed based on the results of genetic tests and ultrasonic evaluation.

Cohesin and human disease

Cornelia de Lange syndrome (CdLS) is a dominant multisystem disorder caused by a disruption of cohesin function. The cohesin ring complex is composed of four protein subunits and more than 25 additional proteins involved in its regulation. The discovery that this complex also has a fundamental role in long-range regulation of transcription in Drosophila has shed light on the mechanism likely responsible for its role in development. In addition to the three cohesin proteins involved in CdLS, a second multisystem, recessively inherited, developmental disorder, Roberts-SC phocomelia, is caused by mutations in another regulator of the cohesin complex, ESCO2. Here we review the phenotypes of these disorders, collectively termed cohesinopathies, as well as the mechanism by which cohesin disruption likely causes these diseases.

First report of a partial trisomy 3q12-q23 de novo--FISH breakpoint determination and phenotypic characterization

We present a 1-year-old boy with mild mental retardation, postnatal growth retardation, and facial dysmorphisms such as frontal bossing, laterally accentuated bushy eyebrows, deep set eyes with long lashes, hypertelorism, and a broad nasal bridge. Except for hip dysplasia, no congenital malformations were detected. By conventional cytogenetics a derivative chromosome 3 de novo was diagnosed which was identified as tandem dup(3)(q12q23) by fluorescence in situ hybridization (FISH) applying arm specific paints and eight different YAC-probes. The duplicated segment lies proximally from the reported dup(3q) syndrome critical region, thus explaining the absence of characteristic phenotypic features of dup(3q) syndrome. To our knowledge this is the first report of a patient with pure trisomy of this proximal region of the long arm of chromosome 3.