Ring chromosome 15: report of a case in an infertile man

The phenotype and rhGH treatment response of ring Chromosome 15 Syndrome: Case report and literature review

Background

Ring chromosome 15 [r (15)] is an uncommon finding with various clinical manifestations. A common phenotype for these patients has not been established and data on the efficacy of recombinant human growth hormone (rhGH) treatment in patients with r (15) syndrome are limited.

Methods

One short stature patient in our hospital with r (15) syndrome by whole exome sequencing (WES) and karyotype examination was included. All published r (15) syndrome cases as of March 15, 2021, were searched, and their clinical information was recorded and summarized.

Results

One 11.5‐year‐old female with prenatal and postnatal growth retardation, ventricular septal defect, intellectual disability, downward corners, short fifth metacarpal bone, scattered milk coffee spots, and a right ovarian cyst was included. Her height was 126.9 cm (−3.45 SDS). Karyotype analysis showed 46, XX, r (15). WES revealed a 4.5 Mb heterozygous deletion in the chromosome 15q26.2‐q26.3 region, encompassing genes from ARRDC4 to OR4F15. Gonadotrophin‐releasing hormone analogue (triptorelin) and rhGH were administered for 6 months. The height has increased 3.8 cm (+0.2SDS) and the calculated growth rate has improved from 4.7 to 7.6 cm/y. The literature review indicated the main clinical manifestations of r (15) syndrome with prenatal and postnatal growth retardation, characteristic craniofacial features, and multisystem abnormalities, and rhGH treatment is beneficial for r (15) syndrome patients with short stature.

Conclusion

We delineate the clinical spectrum of r (15) syndrome with the identification of an additional individual and rhGH treatment is beneficial for r (15) syndrome patients with short stature.

Ring chromosome 15 - cytogenetics and mapping arrays: a case report and review of the literature

BACKGROUND

Ring chromosome 15 has been associated in previous studies with different clinical characteristic such as cardiac problems, digit and musculoskeletal abnormalities, and mental and motor problems among others. Only 97 clinical cases of ring chromosome 15 syndrome have been reported since 1966 and a common phenotype for these patients has not been established.

CASE PRESENTATION

The present case report describes a 15-month-old girl from the Amazon region of Ecuador, of Mestizo ancestry, who after cytogenetic tests showed a 46,XX,r(15) karyotype in more than 70% of metaphases observed. Her parents were healthy and non-related. The pregnancy was complicated and was positive for intrauterine growth retardation. Her birth weight was 1950 g, her length was 43.5 cm, and she had a head circumference of 29.3. In addition to postnatal growth delay, she had scant frontal hair, small eyes, hypertelorism, low-set of ears, flattened nasal bridge, anteverted nostrils, down-turned mouth, three café au lait spots, and delayed dentition.

CONCLUSIONS

Despite the frequency of some phenotypes expressed in the different clinical cases reviewed and the present case, a common phenotype for patients with ring 15 could not be determined and it is restricted to the region of the chromosome lost during the ring formation.

The normality of sperm in an infertile man with ring chromosome 15: a case report

PURPOSE

The purpose of this report is to analyze the chromosome status and fertilization capability of sperm obtained from an infertile male patient with ring chromosome 15.

METHODS

This was a case report at a private in vitro fertilization clinic. A man diagnosed with severe oligozoospermia carrying ring chromosome 15. To evaluate the chromosome status and fertilization capability, sperm from a patient carrying ring chromosome 15 were injected into enucleated mouse oocytes.

RESULTS

The karyotypes of motile sperm from a patient carrying ring chromosome 15 were normal, and ring chromosome 15 was not observed in the chromosome spread samples of 1PN. In addition, these motile sperm retained the fertilization capability. However, the fertilization rates decreased (85.2, 76.2, and 64.3%, respectively) along with the decline of the aspect ratio of the sperm head (≥ 1.50, 1.30-1.49, and < 1.30, respectively).

CONCLUSIONS

The karyotypes were normal without ring chromosome 15, and motile sperm with a high aspect ratio showed adequate potential for fertilization.

Meiotic prophase I defects in an oligospermic man with Wolf-Hirschhorn syndrome with ring chromosome 4

Background

Ring chromosomes are often associated with spermatogenetic failure. However, the mechanism is poorly understood. We here reported a single man with severe oligospermia and a ring chromosome 4 with a microdeletion at 4p16.3.

Results

Synapsis (as SCP3), recombination (as MLH1) and transcriptional inactivation (as BRCA1) in a testicular biopsy were examined by fluorescence immunostaining. In the oligospermia patient, 35.4% of spermatocytes were in zygotene phase compared with 5.2% in controls. The patient had a significantly reduced recombination frequency with mean of 45.9 MLH1 foci/cell compared with 47.8 in controls. In the patient, chromosome 4 in all pachytene cells displayed loop formation with varying degrees of unpaired regions. BRCA1 localized along asynapsed regions regardless of XY body association.

Conclusions

Ring chromosome 4 might affect the progression of meiosis I prophase, synapse formation, and transcriptional activation of asynapsed areas, and impair male fertility.

Azoospermia and paternal autosomal ring chromosomes: case report and literature review

Two men of the same family presented with ring chromosome 22 and azoospermia. The literature on all autosomal ring chromosomes and semen abnormalities was reviewed. Autosomal ring chromosomes were often associated with a low sperm count. This is probably as a result of gamete instability at meiosis due to the ring chromosome which leads to an increased breakdown. In addition, ring chromosomes transmitted from the parents may manifest quite differently in the progeny. Prior to treating these patients with assisted reproduction, appropriate counselling should be offered, in view of the varying phenotypic manifestations of ring chromosomes in the resulting progeny, and prenatal diagnosis or preimplantation diagnosis must be considered.

De novo subtelomeric deletion of 15q associated with satellite translocation in a child with developmental delay and severe growth retardation

We report on a case of satellited 15q with subtelomeric deletion in a girl with delayed development and severe growth retardation. The patient also has a triangular face, downturned angles of the mouth, micrognathia, and minor limb malformations including mild talipes equinovarus, genu recurvatum, and increased dorsiflexion of both limbs. Cytogenetic analysis using standard GTG banding showed a female karyotype with a satellited-like structure at the distal long arm of one chromosome 15. Silver staining of the nucleolar organizing region (AgNOR) confirmed the presence of a satellite DNA translocation at the lesion. Analysis using fluorescent in situ hybridization (FISH) detected a subtelomeric deletion of the terminal 15q. Additional molecular analysis using microsatellite markers along the long arm of chromosome 15 defined a maximally deleted region at approximately 4.7 Mb. Haploinsufficiency of the IGF1R gene expression is thought to be the cause of growth delay in all 15q terminal deletion including our patient.

Familial occurrence of ring chromosome 15

We present a family with the ring 15 chromosome (r(15)) syndrome in a 2-year-old infant and his mother. Both had the common clinical manifestations reported in previous cases with r(15), including severe short stature, microcephaly, triangular face, and mild mental retardation. The family also had a normal son. Although males with r(15) syndrome usually seem to be infertile, female r(15) patients are likely to be fertile and their reproductivity may be influenced by severe growth retardation.

A case of ring chromosome 15 accompanied by almost normal intelligence

A further case of ring chromosome 15 in a 12-year-old boy with growth failure is described. He had minor congenital anomalies, but almost normal intelligence.

Two patients with ring chromosome 15 syndrome

We report on 2 patients (3 1/2 year-old-male and 6-year-old female) with the ring 15 chromosome syndrome and speech delays and review 25 cases from the literature. The main characteristics of this syndrome include growth retardation (100%), variable mental retardation (95%), microcephaly (88%), hypertelorism (46%), and triangular facies (42%). Other frequent findings include delayed bone age (75%), brachydactyly (44%), speech delay (39%), frontal bossing (36%), anomalous ears (30%), café-au-lait spots (30%), cryptorchidism (30%), and cardiac abnormalities (30%). The average age at diagnosis was 8.1 years. The average maternal and paternal age at the time of birth was 28 and 31 years, respectively.

Severe growth failure associated with atrophic intestinal mucosa and ring chromosome 15

Ring chromosome 15 was detected in a boy with severe growth failure and no dysmorphic features who had previously been found to have an atrophic intestinal mucosa, a finding not observed in about 300 patients with ring autosome reported so far. Of the 137 metaphases examined, 8.1% had secondary aneuploidy produced by the structural and behavioural instability of the ring. Ring derivatives could also be seen in lymphocytes after only one cycle in the culture, indicating that such cells are also generated in vivo. We observed an increased cell death rate in fibroblast culture by Trypan Blue exclusion. These results suggest that there is a continuous in vivo generation of cells with increased mortality resulting in both growth failure and atrophic intestinal mucosa in the patient. The atrophic intestinal mucosa might be a manifestation of ring instability.

Dysplastic features, growth retardation, malrotation of the gut, and fatal ventricular septal defect in a 4-month-old girl with ring chromosome 15

A 20-day-old female neonate was admitted with symptoms caused by a large ventricular septal defect which was subsequently confirmed angiographically. Other clinical findings were pre- and postnatal growth retardation, microcephaly, dysmorphism of ears, fingers and feet. Cytogenetic analysis revealed a ring chromosome 15. Despite a palliative banding operation of the pulmonary artery, the infant succumbed to complications of her congenital heart disease in the 4th month of life.

Familial inv(1) (p3500q21.3) associated with azoospermia

An inv(1) (p3500q21.3) was found in an azoospermic man, his mother and two other maternal relatives. Although the mechanisms involved are still unclear, it is stressed that pericentric inversions of chromosome 1 in which the inverted chromosome becomes submetacentric (centromeric index less than or equal to 0.324) apparently impair spermatogenesis.