Clinical heterogeneity in children with gonadal dysgenesis associated with non-mosaic 46,XY karyotype

Systematic Review of Genotype-Phenotype Correlations in Frasier Syndrome

Introduction

Frasier syndrome (FS) is a rare inherited kidney disease caused by intron 9 splicing variants of WT1. For wild-type WT1, 2 active splice donor sites in intron 9 cause a mixture of 2 essential transcripts (with or without lysine-threonine-serine [+/KTS or −KTS]), and imbalance of the +KTS/−KTS ratio results in the development of FS. To date, 6 causative intron 9 variants have been identified; however, detailed transcript analysis has not yet been conducted and the genotype-phenotype correlation also remains to be elucidated.

Methods

We conducted an in vitro minigene splicing assay for 6 reported causative variants and in vivo RNA sequencing to determine the +KTS/−KTS ratio using patients’ samples. We also performed a systematic review of reported FS cases with a description of the renal phenotype.

Results

The in vitro assay revealed that although all mutant alleles produced −KTS transcripts only, the wild-type allele produced both +KTS and −KTS transcripts at a 1:1 ratio. In vivo RNA sequencing showed that patients’ samples with all heterozygous variants produced similar ratios of +KTS to −KTS (1:3.2−1:3.5) and wild-type kidney showed almost a 1:1 ratio (1:0.85). A systematic review of 126 cases clarified that the median age of developing ESKD was 16 years in all FS patients, and there were no statistically significant differences between the genotypes or sex chromosome karyotypes in terms of the renal survival period.

Conclusion

Our study suggested no differences in splicing pattern or renal survival period among reported intron 9 variants causative of FS.

XY Gonadal Dysgenesis in a Phenotypic Female Identified by Direct-to-Consumer Genetic Testing

We report a 16-year-old phenotypic female with 46,XY complete gonadal dysgenesis and metastatic dysgerminoma, unexpectedly discovered through direct-to-consumer (DTC) commercial genetic testing. This case underscores the importance of timely interdisciplinary care, including psychosocial intervention and consideration of gonadectomy, to optimize outcomes for individuals with differences of sex development. Her unique presentation highlights the implications of DTC genetic testing in a new diagnostic era and informs general pediatricians as well as specialists of nongenetic services about the value, capabilities, and limitations of DTC testing.

The Evaluation of Cases with Y-Chromosome Gonadal Dysgenesis: Clinical Experience over 18 Years

OBJECTIVE

Y-chromosome gonadal dysgenesis (GD) is a rare subgroup of disorders of sexual development (DSD) which results from underdeveloped testis and may exhibit heterogenous symptoms. These patients are phenotypically classified into two groups - complete and partial, and their karyotypic description is either 46,XY GD or 45,X/46,XY GD. In this study; we aimed to evaluate the characteristics of cases with Y-chromosome GD.

METHODS

Thirty eight cases were followed-up between 1998 and 2016. The age of admission ranged between 0 and 17 years. Clinical and laboratory findings as well as follow-up characteristics of the cases were evaluated retrospectively from the patient files.

RESULTS

There were 26 cases (four complete, 22 partial) in the 46,XY GD group, and 12 cases (four complete, 8 patients with complete GD in the 45,X/46,XY. Mean age at admission was 6.2±4.6 years for all cases. Patients with complete GD in the 45,X/46,XY GD group were diagnosed earlier that the patients with complete GD in the 46,XY group [11 years vs. 14.31 years of age (p<0.01)]. There were no additional findings in 55% of all patients. In the remaining 45% additional clinical findings, mainly short stature, were detected in 75% of the patients in the 45,X/46,XY GD and 30% of the patients in the 46,XY GD groups. All patients with complete 46,XY and 45,X/46,XY GD were raised as females. There was no gender dysphoria in patients that were raised as females, except for one case. Gonadectomy was performed in 14 patients, at a mean age of 8.75±2.3 years and pathological assessment of the gonads was reported as normal in all cases.

CONCLUSION

Y-chromosome GD is a very heterogenous clinical and genetic disorder and requires a multifaceted approach to management. Whether including syndromic features or not, associated clinical features may lead to earlier diagnosis, especially in complete forms of GD. Due to difficulties encountered in the long-term follow-up of these patients, evaluation of appropriateness of sex of rearing decision is not truly possible. Performance of gonadectomy during the first decade appears be a preventive factor for tumor development since these tumors are usually seen during the second decade.