Prenatal diagnosis of a fetus with ring chromosomal 15 by two- and three-dimensional ultrasonography

Analysis of genetic characteristics of 436 children with dysplasia and detailed analysis of rare karyotype

Chromosomal abnormality is one of the important causes of dysplasia in children. However, due to regional and ethnic differences, the reported rates of chromosomal abnormalities in patients with dysplasia vary greatly. Moreover, the clinical manifestations in children with rare chromosomal diseases were heterogeneous. So, we retrospectively analyzed the karyotype results of 436 children with dysplasia and conducted a detailed analysis of rare chromosomal diseases. The results showed that chromosomal abnormalities were present in 181 of 436 cases. Intellectual disability, dysmorphology, congenital malformations, the disorder of sexual development, and short stature were the main five clinical symptoms in children with chromosomal abnormalities. Moreover, 136 cases of Trisomy 21 (Tri21) were detected, of which 130 were standard Tri21, 5 were robertsonian Tri21, and 1 was chimera type. In addition, 16 cases of rare abnormal karyotype, including complex Tri21, complex Turner syndrome, 4p-syndrome, 18q-syndrome, and 5p-syndrome, were also detected. In summary, chromosome abnormality is one of the important causes of dysplasia in children. Furthermore, prenatal screening and diagnosis could play a great significance in preventing dysplasia in children. In addition, the retrospective analysis of rare cases is valuable for clinical diagnosis and risk assessment of recurrence.

Prenatal Sonographic Features of Ring Chromosome 15: A Case Report and Literature Review

Ring chromosome 15, a rare genetic disease, is very rarely prenatally diagnosed. We present a unique case of fetal ring chromosome 15 with ultrasound findings at 32 weeks of gestation including congenital diaphragmatic hernia, hypoplasia of the aorta with persistent left SVC, growth restriction, clubfeet and scoliosis. We also performed an analytical literature review of prenatal sonographic findings of the disease. This review suggests that ring chromosome 15 has a relatively specific sonographic pattern that could facilitate early detection. The specific sonographic features of ring chromosome 15 include fetal growth restriction, congenital diaphragmatic hernia, abnormal limb postures, cardiac defects, low-set ears and other less frequent, non-specific anomalies that can be identified in more than 50% of cases.

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.

Chromosome 15 structural abnormalities: effect on IGF1R gene expression and function

Insulin-like growth factor 1 receptor (IGF1R), mapping on the 15q26.3 chromosome, is required for normal embryonic and postnatal growth. The aim of the present study was to evaluate the IGF1R gene expression and function in three unrelated patients with chromosome 15 structural abnormalities. We report two male patients with the smallest 15q26.3 chromosome duplication described so far, and a female patient with ring chromosome 15 syndrome. Patient one, with a 568 kb pure duplication, had overgrowth, developmental delay, mental and psychomotor retardation, obesity, cryptorchidism, borderline low testis volume, severe oligoasthenoteratozoospermia and gynecomastia. We found a 1.8-fold increase in the IGF1R mRNA and a 1.3-fold increase in the IGF1R protein expression (P < 0.05). Patient two, with a 650 kb impure duplication, showed overgrowth, developmental delay, mild mental retardation, precocious puberty, low testicular volume and severe oligoasthenoteratozoospermia. The IGF1R mRNA and protein expression was similar to that of the control. Patient three, with a 46,XX r(15) (p10q26.2) karyotype, displayed intrauterine growth retardation, developmental delay, mental and psychomotor retardation. We found a <0.5-fold decrease in the IGF1R mRNA expression and an undetectable IGF1R activity. After reviewing the previously 96 published cases of chromosome 15q duplication, we found that neurological disorders, congenital cardiac defects, typical facial traits and gonadal abnormalities are the prominent features in patients with chromosome 15q duplication. Interestingly, patients with 15q deletion syndrome display similar features. We speculate that both the increased and decreased IGF1R gene expression may play a role in the etiology of neurological and gonadal disorders.

Pre- and Postnatal Analysis of Chromosome 15q26.1 and 8p23.1 Deletions in Congenital Diaphragmatic Hernia

Congenital diaphragmatic hernia (CDH) is defined as a protrusion of abdominal content into the thoracic cavity through an abnormal opening in the diaphragm present at birth. It is a common birth defect with high mortality and morbidity. Submicroscopic deletions of 15q26.1 and 8p23.1 have been reported in several cases of CDH. We studied a total of 17 cases with CDH in pre- and postnatal samples using FISH probes. Deletion 15q26.1 was seen in 1/17 prenatal samples. There was no deletion for 8p23.1 in all the samples analyzed. CDH has a genetic etiology, and deletion 15q26.1 increases the risk of CDH. Deletion 15q26.1 in a fetus with CDH is a predictor of poor prognosis. This deletion is also seen in a phenotype similar to Fryns syndrome. CDH identified pre- or postnatally should be investigated further to exclude a 15q26.1 deletion and enable appropriate parental counseling.