Congenital malformations associated with a ring 4 chromosome

The past, present, and future for constitutional ring chromosomes: A report of the international consortium for human ring chromosomes

Human ring chromosomes (RCs) are rare diseases with an estimated newborn incidence of 1/50,000 and an annual occurrence of 2,800 patients globally. Over the past 60 years, banding cytogenetics, fluorescence in situ hybridization (FISH), chromosome microarray analysis (CMA), and whole-genome sequencing (WGS) has been used to detect an RC and further characterize its genomic alterations. Ring syndrome featuring sever growth retardation and variable intellectual disability has been considered as general clinical presentations for all RCs due to the cellular losses from the dynamic mosaicism of RC instability through mitosis. Cytogenomic heterogeneity ranging from simple complete RCs to complex rearranged RCs and variable RC intolerance with different relative frequencies have been observed. Clinical heterogeneity, including chromosome-specific deletion and duplication syndromes, gene-related organ and tissue defects, cancer predisposition to different types of tumors, and reproductive failure, has been reported in the literature. However, the patients with RCs reported in the literature accounted for less than 1% of its occurrence. Current diagnostic practice lacks laboratory standards for analyzing cellular behavior and genomic imbalances of RCs to evaluate the compound effects on patients. Under-representation of clinical cases and lack of comprehensive diagnostic analysis make it a challenge for evidence-based interpretation of clinico-cytogenomic correlations and recommendation of follow-up clinical management. Given recent advancements in genomic technologies and organized efforts by international collaborations and patient advocacy organizations, the prospective of standardized cytogenomic diagnosis and evidence-based clinical management for all patients with RCs could be achieved at an unprecedented global scale.

Clinical, cytogenetic, and molecular findings in a patient with ring chromosome 4: case report and literature review

Background

Since 1969, 49 cases have been presented on ring chromosome 4. All of these cases have been characterized for the loss of genetic material. The genes located in these chromosomal regions are related to the phenotype.

Case presentation

A 10-year-old Ecuadorian Mestizo girl with ring chromosome 4 was clinically, cytogenetically and molecularly analysed. Clinical examination revealed congenital anomalies, including microcephaly, prominent nose, micrognathia, low set ears, bilateral clinodactyly of the fifth finger, small sacrococcygeal dimple, short stature and mental retardation. Cytogenetic studies showed a mosaic karyotype, mos 46,XX,r(4)(p16.3q35.2)/46,XX, with a ring chromosome 4 from 75 to 79% in three studies conducted over ten years. These results were confirmed by fluorescence in situ hybridization (FISH). Loss of 1.7 Mb and gain of 342 kb in 4p16.3 and loss of 3 Mb in 4q35.2 were identified by high-resolution mapping array.

Conclusion

Most cases with ring chromosome 4 have deletion of genetic material in terminal regions; however, our case has inv dup del rearrangement in the ring chromosome formation. Heterogeneous clinical features in all cases reviewed are related to the amount of genetic material lost or gained. The application of several techniques can increase our knowledge of ring chromosome 4 and its deviations from typical “ring syndrome.”

Ring Chromosome 4 in a Child with Multiple Congenital Abnormalities: A Case Report and Review of the Literature

A female child born preterm with intrauterine growth retardation and presenting with facial dysmorphism with clefts, microcephaly, limb deformities, and congenital abnormalities involving cardiovascular and urinary systems is described. Chromosomal analysis showed a de novo 46,XX,r(4)(p15.3q35) karyotype. The clinical features of the patient were compared with the phenotypic characteristics of 17 previously reported cases with ring chromosome 4 and those with Wolf-Hirschhorn syndrome (4p-). Clinical features observed in this case are consistent with the consensus phenotype in ring chromosome 4. Patent ductus arteriosus and bilateral talipes equinovarus observed in this baby widen the phenotypic spectrum associated with ring chromosome 4.

Ring chromosome 4 and Wolf–Hirschhorn syndrome (WHS) in a child with multiple anomalies

We report on a 16-month-old male patient with ring chromosome 4 and deletion of Wolf-Hirschhorn syndrome (WHS) region with multiple congenital anomalies including unilateral cleft lip and palate, iris coloboma, microcephaly, midgut malrotation, hypospadias, and double urethral orifices. Peripheral chromosome analysis of the patient showed 46,XY,r(4)(p16.3q35) de novo. Multicolor fluorescence in situ hybridization (FISH) study was also performed and according to multicolor banding (MCB) a r(4)(::p16.3 --> q34.3 approximately 35.1::) was found in all metaphases. Subtelomeric 4p region, subtelomeric 4q region, as well as, Wolf-Hirschhorn critical region were deleted in ring chromosome 4. Genomic microarray analysis was also performed to delineate the size of deletion. Cranial magnetic resonance imaging (MRI) showed hypoplastic corpus callosum, delayed myelinization, and frontal and occipital lobe atrophies. Both maternal and paternal chromosomal analyses were normal. We compare the phenotypic appearance of our patient with the previously reported 16 cases of ring chromosome 4 in the medical literature.

Ring chromosome 4 in a patient with early onset type 2 diabetes, deafness, and developmental delay

To date, most ring formations of chromosome 4 lose distal 4p and usually include the Wolf-Hirschhorn syndrome region [WHS]. We describe a case with r(4) in a girl who presented without features of WHS; she had mild developmental delay, deafness, short stature, obesity, and the onset of type 2 diabetes in adolescence, a distinctive phenotype. Although 4p was significantly deleted on Giemsa banding, the 4p junction was distal to the WHS and FGFR3 but proximal to the D4S3360 marker. The 4q breakpoint was close to the telomere. The phenotype appears different from previous patients with 4p- or r(4), which have had more extensive 4p deletion.

Ocular colobomata

Ocular colobomata present diagnostic and therapeutic challenges in patients of all ages, but especially in young children. The "typical" coloboma, caused by defective closure of the fetal fissure, is located in the inferonasal quadrant, and it may affect any part of the globe traversed by the fissure from the iris to the optic nerve. Ocular colobomata are often associated with microphthalmia, and they may be idiopathic or associated with various syndromes. Types and severity of complications vary depending on the location and size of the colobomata. This article reviews the pathogeneses, categorization, genetic bases, differential diagnoses and management of ocular coloboma.

Mechanisms of small ring formation suggested by the molecular characterization of two small accessory ring chromosomes derived from chromosome 4

Molecular cloning of a microdissected small accessary ring chromosome 4 from a moderately retarded and dysmorphic patient has been performed to identify the origin of the ring chromosome. FISH was performed with cosmids identified with the cloned, microdissected products and with other markers from chromosome 4. The present study clearly demonstrates that the small ring in this patient originates from three discontinuous regions of chromosome 4: 4p13 or 14, the centromere, and 4q31. It is suggested that the origin of the ring chromosome is a ring involving the entire chromosome 4, which has then been involved in breakage and fusion events, as a consequence of DNA replication generating interlocked rings. A second severely retarded and dysmorphic patient also had a small accessary ring derived from chromosome 4. FISH studies of this ring are consistent with an origin from a contiguous region including the centromere to band 4q12. It is apparent that there are at least two mechanisms for the formation of small ring chromosomes. This adds a further complication in any attempt to ascertain common phenotypes between patients known to have morphologically similar markers derived from the same chromosome.

Further study of genetic interactions: loss of short arm material in patients with ring chromosome 4 changes developmental pattern of del(4)(q33)

Segment 4q33 is not considered a probable location of a gene related with limb deficiency by Roberts and Tabin [Am J Hum Genet 55:1-6, 1994]; however, the occurrence of ectrodactyly or its equivalents in at least 9 published cases of monosomy 4q33 suggests probable location of one of these genes in that region. Ulnar ray defects and/or ectrodactyly were the prevailing forms. An additional loss of the tip of 4p in patients with ring chromosome 4 leads to a change of limb deficiency type: 8 of 9 patients with r(4) and limb deficiency had radial ray defects. Therefore, interactions between a proposed 1/2 dose "ectrodactyly" gene on 4q33 and some 1/2 dosage genes on distal 4p (or disturbed cellular homeostasis due to a ring chromosome 4) can change the developmental pattern of limb deficiency. Possible mechanisms and significance of the phenomenon are discussed.

Deletion of the terminal segment of the long arm of chromosome 4 with aortic stenosis

A dysmorphic Chinese baby girl was found to have deletion of the long arm of chromosome 4 (46XX, del[4] q33-->qter). A review of various case reports of deletion of the long arm of chromosome 4 is reported and the clinical features are identified and compared. The earlier reports on this condition were that of deletion of the terminal segment of the long arm with break point occurring at q31. Since 1981, cases of deletion with break point at q33 have been reported.

Ring chromosome 4 in a child with mild dysmorphic signs

We report on an 8-year-old boy exhibiting microcephaly, clinodactyly and growth retardation. Chromosome analysis showed a ring chromosome 4 in 97% of the cells and a high number of hyperploid cells with various ring formations. The breakpoints are presumed to be close to or in the telomeric regions of both arms. The patients reported with ring chromosome 4 and breakpoints close to the telomeres of both arms showed unspecific, mild clinical findings with normal or retarded mental development. These signs are probably related to the continuous generation of aneuploid cells.

Wolf syndrome

Since the initial description in 1965 of Wolf syndrome, or deletion of the short arm of chromosome number four, over one hundred cases have been reported. Much less, however, has been published on the radiologic findings in this disorder. We report a case with both typical and unusual features of the 4p- syndrome, including "bottle opener" deformity of the clavicles, and review the relevant literature.

Ring chromosome 4 in a child with duodenal atresia

We report on a 19-month-old girl with ring chromosome 4 and a multiple congenital anomaly syndrome. The clinical and cytogenetic findings are compared with those of previous cases in whom the breakpoints in ring chromosome 4 are known.

Genetics in pediatric ophthalmology

Genetic factors are becoming increasingly important causes of both congenital and acquired eye disease in the pediatric age group. Referral to an ophthalmologist is important both for global genetic disorders potentially affecting the eye and for eye disorders that may be diagnostic for genetic disease.

Neurological and neuropathological findings in ring chromosome 4

Despite the fact that mental retardation, microcephaly, seizures, and hyperactivity are common in patients with ring chromosome 4, little has been written about the underlying neuropathology. We describe a 6-year-old girl whose neuropathological findings included low brain weight, abnormal gyral development, and heterotopic neurons. The significance of these findings in regard to other retardation syndromes is discussed.

The 4p- syndrome--an autopsy study

The autopsy of an infant with the 4p- or Wolf-Hirschhorn syndrome revealed visceral abnormalities not previously described, i.e., agencies of the gallbladder and spleen. The parents' chromosomes were normal.

The Wolf-Hirschhorn syndrome. II. Pathologic anatomy

Most cases of Wolf-Hirschhorn syndrome occurring among children who die during the perinatal period are not diagnosed by morphologists. However, analysis of the morphological data on the Wolf-Hirschhorn syndrome revels that association of typical external features and abnormalities ofthe brain (shortening of the H2 area of Ammon's horn, dystonic dysplastic gyrae in the cerebellum), eyes (colobomata, microphthalmos, retinal dysplasia) and kidneys (bilateral or unilateral agenesis, cystic dysplasia or polycystosis) with diaphragmatic hernia allows the establishment of a diagnosis of the syndrome without cytogenetic investigation.

The Wolf-Hirschhorn syndrome. I. Genetics

Four new cases of the Wolf-Hirschhorn syndrome are presented, two of which were due to t(4;22)mat. Review of the literature (more than 100 cases of the Wolf-Hirschhorn syndrome) showed that 13 % of all the reported cases were not mutations but segregations of parental chromosomal aberrations, primarily translocations. Similar data were obtained previously for other deletions (5p--, 18p--, 18q--). Analysis of data on some "new" deletion syndromes (4q--, 8p--, 9p--, 10p--, 11p--, 11q--) revealed that 14.5 % were inherited cases. Thus, all human autosomal deletions have virtually the same genetic pattern.

Translocation of chromosome 4 and 9 with ring formation of chromosome 4 short arm

Cytogenetic investigation of a 3-year-old mentally retarded boy revealed a translocation of the long arm of chromosome 4 onto the short arm of chromosome 9, with ring formation of the remaining short arm of chromosome 4. The clinical features are described and correlated with the cytogenetic findings. The behaviour of the ring derived from a deleted chromosome 4 is discussed.

The Wolf-Hirschhorn (4p-) syndrome

In a review of 43 cases, the phenotypic spectrum of the Wolf-Hirschhorn syndrome is analyzed and the frequency of clinical anomalies is tabulated. The characteristic features are intrauterine growth retardation, severe psychomotor retardation, typical facies, and various major and minor congenital anomalies suggestive of a midline fusion defect. Diagnosis is established by karyotyping- deletion of the short arm of chromosome No. 4. All cases so far reported are de novo occurrences with no sibling involvement and normal parents. Prognosis is poor, with death in the first 2 years of life in 34% of cases, usually due to cardiac decompensation or infection. Psyhomotor retardation is profound, so that heroic medical efforts probably need to be reconsidered.

Derivative chromosomal structures from a ring chromsome 4

This report describes the results from cultured lymphocytes studied at metaphase, anaphase, and interphase from an individual with a ring chromosome 4. A ring was present in 90.1% of metaphases. Special attention was directed towards the occurrence of derivative chromosomal structures, such as partially duplicated and triplicated rings, tricentric rings, chains of 3 interlocked rings, rod-shaped chromosomes, "pulverized" rings, and others. The clinical features of the individual (small stature and impaired mental development, hypoplastic thumbs, ptosis palpebrae hypoplastic external male genitalia, abnormal dermatoglphic pattern) did not conform to a specific phenotype.

A child with multiple congenital malformations and a 46,XX,t(Bq+;Dq-)-45,XX,-B,-D,+der(B),t(Bq+;Dq-) karyotype

A case of a female infant with malformations of upper extremities and mental and growth retardation is reported.

The karyotype showed a 46,XX,t(Bq+;Dq−)/45,XX,−B,−D,+der(B),t(Bq+;Dq−) mosaicism. The clinical findings in relation to the long arm deletion of a B-group chromosome are discussed.

Deletion from the long arm of chromosome 4 (46,XX,4q-) associated with congenital anomalies

A congenitally malformed infant with a partial deletion of the long arm of chromosome 4 identified by Giemsa banding studies is described. The relationship of the anomalies to the chromosome abnormality is discussed.

A ring-4 chromosome in a patient with normal intelligence and short stature

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A complex chromosomal rearrangement with formation of a ring 4

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Child with multiple anomalies and a group B(4-5) long arm deletion (Bq-)

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Wolf-Hirschhorn syndrome associated with an unusual abnormality of chromosome no. 4

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