Xq26.3-q27.1 duplication including SOX3 gene in a Chinese boy with hypopituitarism: case report and two years treatment follow up

Complete F9 Gene Deletion, Duplication, and Triplication Rearrangements: Implications for Factor IX Expression and Clinical Phenotypes

BACKGROUND

 Factor IX (FIX) plays a critical role in blood coagulation. Complete deletion of F9 results in severe hemophilia B, whereas the clinical implications of complete F9 duplication and triplication remain understudied.

OBJECTIVE

 To investigate the rearrangement mechanisms underlying complete F9 deletion (cases 1 and 2), duplication (cases 3 and 4), and triplication (case 5), and to explore their association with FIX expression levels and clinical impacts.

METHODS

 Plasma FIX levels were detected using antigen and activity assays. CNVplex technology, optical genome mapping, and long-distance polymerase chain reaction were employed to characterize the breakpoints of the chromosomal rearrangements.

RESULTS

 Cases 1 and 2 exhibited FIX activities below 1%. Case 3 displayed FIX activities within the reference range. However, cases 4 and 5 showed a significant increase in FIX activities. Alu-mediated nonallelic homologous recombination was identified as the cause of F9 deletion in case 1; FoSTeS/MMBIR (Fork Stalling and Template Switching/microhomology-mediated break-induced replication) contributed to both F9 deletion and tandem duplication observed in cases 2 and 3; BIR/MMBIR (break-induced replication/microhomology-mediated break-induced replication) mediated by the same pair of low-copy repeats results in similar duplication-triplication/inversion-duplication (DUP-TRP/INV-DUP) rearrangements in cases 4 and 5, leading to complete F9 duplication and triplication, respectively.

CONCLUSION

 Large deletions involving the F9 gene exhibit no apparent pattern, and the extra-hematologic clinical phenotypes require careful analysis of other genes within the deletion. The impact of complete F9 duplication and triplication on FIX expression might depend on the integrity of the F9 upstream sequence and the specific rearrangement mechanisms. Notably, DUP-TRP/INV-DUP rearrangements significantly elevate FIX activity and are closely associated with thrombotic phenotypes.

Prenatal detection and molecular cytogenetic characterization of Xp deletion and Xq duplication: a case report and literature review

BACKGROUND

Copy number variation (CNV) of X chromosome can lead to a variety of neonatal abnormalities, especially for male fetuses. In recent years, due to the high sensitivity and high specificity of NIPS, its application has gradually expanded from chromosome aneuploidy to CNV. Few prenatal cases involving the detection of Xq duplication and deletion by NIPS have been reported, but it is of great significance for genetic counseling.

CASE PRESENTATION

A 36-year-old woman was referred for prenatal diagnosis and genetic counseling at 17 weeks of gestation because of abnormal result of noninvasive prenatal screening (NIPS). Multiple congenital malformations, hydrocephalus, and enlarged gallbladder were observed by prenatal ultrasound. Amniocentesis revealed the karyotype of the fetus as 46, XN, add(X) (p22.2) and the result of chromosomal microarray analysis was arr[hg19] Xq27.1q28(138,506,454-154896094) × 2 and arr[hg19] Xp22.33p22.32(168,551-5,616,964) × 1. CNV-seq showed that the mother shares a 16.42 Mb duplication in the Xq27.1-q28 region and a 2.97 Mb deletion in the Xp22.33-p22.32 region. After genetic counseling, the couple chose to terminate the pregnancy.

CONCLUSION

The combination of NIPS and CMA would be of values in detection of subchromosomal duplications and/or deletions at fetal stage. The detection of X chromosome aberration in a male fetus should give suspicion of the possibility of maternal inheritance.

The presence and distribution of various genes in postnatal CLP-affected palatine tissue

BACKGROUND

Worldwide cleft lip with or without a cleft palate (CL/P) is the most common craniofacial birth defect. Apart from changes in facial appearance, additionally affected individuals often suffer from various associated comorbidities requiring complex multidisciplinary treatment with overall high expenses. Understanding the complete pathogenetic mechanisms of CL/P might aid in developing new preventative strategies and therapeutic approaches, help with genetic counselling, and improve quality of life. Many genes have been associated with the development of orofacial clefts; however, the majority require further research. Based on the role of PAX7, PAX9, SHH, SOX3, WNT3A, and WNT9B in orofacial development, the intention was to use chromogenic in situ hybridization to detect the six genes in postnatal CLP-affected palatine tissue and compare their distribution within the tissue samples.

RESULTS

Statistically significant differences in the distribution of PAX7, PAX9, WNT3A, and WNT9B were observed. In total, 19 pairs of moderate to very strong positive correlations were noted.

CONCLUSIONS

Changes in the cleft-affected palatine epithelium primarily seem to be associated with the PAX7 gene; however, PAX9, WNT3A, WNT9B, and SOX3 role seems to be more limited. Whilst connective tissue changes seem to depend on PAX7 only, SHH seems to participate individually and indistinctly. Numerous positive correlations reflect the complicating interactions of the pathways and their components in the orofacial cleft morphopathogenesis.

The clinical aspects of septo-optic dysplasia: A narrative review with illustrative case report

INTRODUCTION AND IMPORTANCE

Septo-optic dysplasia (SOD) is a rare congenital disorder characterized by abnormal development of the optic nerve, pituitary gland, hypothalamus, and midline brain structures, with heterogeneous presentation among cases.

CASE PRESENTATION

We report a seven-month-old male infant presented with persistent vomiting and delayed developmental milestones. He had dysmorphic facial features, bilateral esotropia, a head circumference of 50 cm, and scoliosis. His muscle tone was high (clasp-knife spasticity) and his deep tendon reflexes were brisk in the four limbs. Clinical evaluation and brain MRI confirmed the diagnosis of SOD, for which, he was subjected for multidisciplinary evaluation. Genetic testing revealed an autosomal dominant TUBB gene mutation. On follow-up, at the age of three years, he presented with recurrent focal motor and generalized seizures, which were controlled with levetiracetam.

CLINICAL DISCUSSION

The ophthalmic manifestations of SOD include optic nerve hypoplasia, which can lead to visual impairments such as nystagmus, strabismus, and reduced visual acuity. Midline brain anomalies involve structures like the corpus callosum and septum pellucidum, and can result in cognitive and neurological deficits. Hypothalamic-pituitary axis abnormalities can cause endocrine dysfunction and growth abnormalities. The clinical heterogeneity of SOD is attributed to variable phenotypic penetration and genetic mutations. Environmental risk factors may also contribute to the development of the syndrome.

CONCLUSION

SOD is a complex disorder with diverse clinical manifestations. Early diagnosis and multidisciplinary management are crucial for optimizing patient outcomes. Further research is needed to understand the underlying genetic and environmental factors involved in SOD and to develop targeted treatments.

Duplication of SOX3 in an SRY-negative 46,XX male with prostatic utricle: case report and literature review

BACKGROUND

46,XX male disorders of sex development are rare. Approximately 80% of cases of testicular tissue differentiation may be due to translocation of SRY to the X chromosome or an autosome. SRY-negative 46,XX males show overexpression of pro-testis genes, such as SOX9 and SOX3, or failure of pro-ovarian genes, such as WNT4 and RSPO1, which induces testis differentiation, however, almost all testicles exhibit dysgenesis. Following inadequate exposure to androgens during the embryo stage, remnants of the Mullerian duct and incomplete closure of the urogenital sinus lead to enlargement of prostatic utricles. This condition is associated with proximal hypospadias and disorders of sex development. Many cases are asymptomatic, but show increased rates of postoperative complications and surgical failure.

CASE PRESENTATION

A 5-year-old Chinese boy with scrotal hypospadias and bilateral cryptorchidism with prostatic utricles was presented. Gonadal histology showed ovo-testicular tissue on the right side and testicular tissue on the left side; all testicular tissue exhibited dysgenesis. Furthermore, chromosome karyotype analysis revealed 46,XX and, the presence of SRY was ruled out by polymerase chain reaction analysis. Whole-genome analysis showed the boy has a 1.4-Mb duplication in the Xq27.1q27.2 region (arr[hg19]Xq27.1q27.2:139585794-140996652) involving SOX3. No SOX3 duplication was observed in the parents, who had a normal phenotype.

CONCLUSIONS

We report the first case of an SRY-negative 46 XX male with prostatic utricle caused by SOX3 duplication. SOX3 duplication may cause sex reversal, and all 46,XX SRY-negative males should be screened for SOX3 mutations. Gonadal biopsy is recommended to evaluate ovarian and testicular tissue development. Testicular dysgenesis and low exposure to male hormones during fetal development can lead to enlarged prostatic utricles. Thus endoscopic examination should be performed preoperatively to detect prostatic utricles in SRY-negative 46,XX males to determine the surgical plan and reduce postoperative complications.