Biallelic Mutations in FUT8 Cause a Congenital Disorder of Glycosylation with Defective Fucosylation.

Fucosyltransferase 8 (FUT8) encodes a Golgi-localized α1,6 fucosyltransferase that is essential for transferring the monosaccharide fucose into N-linked glycoproteins, a process known as "core fucosylation." Here we describe three unrelated individuals, who presented with intrauterine growth retardation, severe developmental and growth delays with shortened limbs, neurological impairments, and respiratory complications. Each underwent whole-exome sequencing and was found to carry pathogenic variants in FUT8. The first individual (consanguineous family) was homozygous for c.715C>T (p.Arg239∗), while the second (non-consanguineous family) was compound heterozygous for c.1009C>G (p.Arg337Gly) and a splice site variant c.1259+5G>T. The third individual (consanguineous family) was homozygous for a c.943C>T (p.Arg315∗). Splicing analysis confirmed the c.1259+5G>T resulted in expression of an abnormal FUT8 transcript lacking exon 9. Functional studies using primary fibroblasts from two affected individuals revealed a complete lack of FUT8 protein expression that ultimately resulted in substantial deficiencies in total core fucosylated N-glycans. Furthermore, serum samples from all three individuals showed a complete loss of core fucosylation. Here, we show that loss of function mutations in FUT8 cause a congenital disorder of glycosylation (FUT8-CDG) characterized by defective core fucosylation that phenotypically parallels some aspects of the Fut8-/- knockout mouse. Importantly, identification of additional affected individuals can be easily achieved through analysis of core fucosylation of N-glycans.

Mosaicism of the UDP-Galactose transporter SLC35A2 in a female causing a congenital disorder of glycosylation: a case report.

BACKGROUND: Congenital disorders of glycosylation are rare conditions caused by genetic defects in glycan synthesis, processing or transport. Most congenital disorders of glycosylation involve defects in the formation or transfer of the lipid-linked oligosaccharide precursor of N-linked glycans. SLC35A2-CDG (previously CDG-IIm) is caused by hemizygous or heterozygous mutations in the X-linked gene SLC35A2 that encodes a UDP-galactose transporter. To date there have only been 10 reported patients with SLC35A2 mutations. Importantly, the patient presented here was not identified in infancy by transferrin isoform analysis, the most common testing to identify patients with a congenital disorder of glycosylation. CASE PRESENTATION: A 27 month old girl with developmental delay, central hypotonia, cerebral atrophy, and failure to thrive with growth retardation was identified by whole exome sequencing to have a mosaic missense variant in SLC35A2 (c.991G > A). This particular variant has been previously reported in a male as a mutation. Comparison of all clinical findings and new information on growth pattern, growth hormone testing and neurodevelopmental evaluation are detailed on the patient presented. CONCLUSION: This patient report increases the clinical and scientific knowledge of SLC35A2-CDG, a rare condition. New information on reduced growth, growth hormone sufficiency, lack of seizures, and neurodevelopmental status are presented. This new information will be helpful to clinicians caring for individuals with SLC35A2-CDG. This report also alerts clinicians that transferrin isoform measurements do not identify all patients with congenital disorders of glycosylation.

A case of a large leiomyomatous uterus with multiple arteriovenous malformations and subsequent high cardiac output state with severe four chamber cardiac enlargement.

Uterine arteriovenous malformations (AVMs) are rare and potentially life-threatening. They can be congenital or acquired. Uterine artery embolization or hysterectomy are considered mainstays of management. AVMs can be associated with leiomyomas, and patients may require both procedures. We present a case of a 42-year-old woman with a massively enlarged leiomyomatous uterus supplied and drained by multiple large AVMs, leading to high cardiac output state with severe four chamber cardiac dilation. Management required a multidisciplinary team of interventional radiology, gynecologic oncology surgery, vascular surgery, cardiac anesthesiology, cardiology, and urology and a 2-day interventional approach of preoperative arterial embolization followed by hysterectomy.

Clinically Actionable Findings Derived From Predictive Genomic Testing Offered in a Medical Practice Setting.

OBJECTIVE: To assess the presence of clinically actionable results and other genetic findings in an otherwise healthy population of adults seen in a medical practice setting and offered "predictive" genomic testing. PATIENTS AND METHODS: In 2014, a predictive genomics clinic for generally healthy adults was launched through the Mayo Clinic Executive Health Program. Self-identified interested patients met with a genomic nurse and genetic counselor for pretest advice and education. Two genome sequencing platforms and one gene panel-based health screen were offered. Posttest genetic counseling was available for patients who elected testing. From March 1, 2014, through June 1, 2019, 1281 patients were seen and 301 (23.5%) chose testing. Uptake rates increased to 36.3% [70 of 193]) in 2019 from 11.8% [2 of 17] in 2014. Clinically actionable results and genetic findings were analyzed using descriptive statistics. RESULTS: Clinically actionable results were detected in 11.6% of patients (35 of 301), and of those, 51.7% (15 of 29) with a cancer or cardiovascular result = did not have a personal or family history concerning for a hereditary disorder. The most common actionable results were in the BCHE, BRCA2, CHEK2, LDLR, MUTYH, and MYH7 genes. A carrier of at least one recessive condition was found in 53.8% of patients (162 of 301). At least one variant associated with multifactorial disease was found in 44.5% (134 of 301) (eg, 25 patients were heterozygous for the F5 factor V Leiden variant associated with thrombophilia risk). CONCLUSION: Our predictive screening revealed that 11.6% of individuals will test positive for a clinically actionable, likely pathogenic/pathogenic variant. This finding suggests that wider knowledge and adoption of predictive genomic services could be beneficial in medical practice, although additional studies are needed.

Genomics Integration Into Nephrology Practice.

RATIONALE & OBJECTIVE: The etiology of kidney disease remains unknown in many individuals with chronic kidney disease (CKD). We created the Mayo Clinic Nephrology Genomics Clinic to improve our ability to integrate genomic and clinical data to identify the etiology of unexplained CKD. STUDY DESIGN: Retrospective study. SETTING & PARTICIPANTS: An essential component of our program is the Nephrology Genomics Board which consists of nephrologists, geneticists, pathologists, translational omics scientists, and trainees who interpret the patient's clinical and genetic data. Since September 2016, the Board has reviewed 163 cases (15 cystic, 100 glomerular, 6 congenital anomalies of kidney and urinary tract (CAKUT), 20 stones, 15 tubulointerstitial, and 13 other). ANALYTICAL APPROACH: Testing was performed with targeted panels, single gene analysis, or analysis of kidney-related genes from exome sequencing. Variant classification was obtained based on the 2015 American College of Medical Genetics and Genomics and the Association for Molecular Pathology guidelines. RESULTS: A definitive genetic diagnosis was achieved for 50 families (30.7%). The highest diagnostic yield was obtained in individuals with tubulointerstitial diseases (53.3%), followed by congenital anomalies of the kidney and urological tract (33.3%), glomerular (31%), cysts (26.7%), stones (25%), and others (15.4%). A further 20 (12.3%) patients had variants of interest, and variant segregation, and research activities (exome, genome, or transcriptome sequencing) are ongoing for 44 (40%) unresolved families. LIMITATIONS: Possible overestimation of diagnostic rate due to inclusion of individuals with variants with evidence of pathogenicity but classified as of uncertain significance by the clinical laboratory. CONCLUSIONS: Integration of genomic and research testing and multidisciplinary evaluation in a nephrology cohort with CKD of unknown etiology or suspected monogenic disease provided a diagnosis in a third of families. These diagnoses had prognostic implications, and often changes in management were implemented.