Revealing hidden genetic diagnoses in the ocular anterior segment disorders.

PURPOSE: Ocular anterior segment disorders (ASDs) are clinically and genetically heterogeneous, and genetic diagnosis often remains elusive. In this study, we demonstrate the value of a combined analysis protocol using phenotypic, genomic, and pedigree structure data to achieve a genetic conclusion. METHODS: We utilized a combination of chromosome microarray, exome sequencing, and genome sequencing with structural variant and trio analysis to investigate a cohort of 41 predominantly sporadic cases. RESULTS: We identified likely causative variants in 54% (22/41) of cases, including 51% (19/37) of sporadic cases and 75% (3/4) of cases initially referred as familial ASD. Two-thirds of sporadic cases were found to have heterozygous variants, which in most cases were de novo. Approximately one-third (7/22) of genetic diagnoses were found in rarely reported or recently identified ASD genes including PXDN, GJA8, COL4A1, ITPR1, CPAMD8, as well as the new phenotypic association of Axenfeld-Rieger anomaly with a homozygous ADAMTS17 variant. The remainder of the variants were in key ASD genes including FOXC1, PITX2, CYP1B1, FOXE3, and PAX6. CONCLUSIONS: We demonstrate the benefit of detailed phenotypic, genomic, variant, and segregation analysis to uncover some of the previously "hidden" heritable answers in several rarely reported and newly identified ocular ASD-related disease genes.

Adult-Diagnosed Nonsyndromic Nephronophthisis in Australian Families Caused by Biallelic NPHP4 Variants.

There is increasing appreciation of nephronophthisis (NPHP) as an autosomal recessive cause of kidney failure and earlier stages of chronic kidney disease among adults. We identified 2 families with presumed adult-diagnosed nonsyndromic NPHP and negative diagnostic genetic testing results from our Renal Genetics Clinic. Both had 2 affected siblings without extrarenal phenotypes. After informed consent, research whole-genome sequencing was undertaken. Biallelic NPHP4 variants were identified in trans and clinically confirmed in all 4 affected individuals, confirming a genetic diagnosis. Participant 1 of the first family (F1P1) had kidney failure diagnosed at 19 years of age. An affected younger sibling (F1P2) reached kidney failure at age 15 years after kidney biopsy suggested NPHP. Pathogenic variants detected in NPHP4 in this family were NM_015102.4:c.3766C>T (p.Gln1256*) and a 31-kb deletion affecting exons 12 to 16. In the second family, F2P3 reached kidney failure at age 27 years having undergone kidney biopsy suggesting NPHP. An affected younger sibling (F2P4) has chronic kidney disease stage 4 at age 39 years. The NPHP4 variants detected were NM_015102.4:c.1998_1999del (p.Tyr667Phefs*23) and c.3646G>T (p.Asp1216Tyr). The latter variant was initially missed in diagnostic sequencing due to inadequate NPHP4 coverage (94.3% exonic coverage). With these reports, we identify NPHP4 as an appreciable genetic cause for adult-diagnosed nonsyndromic NPHP that should be considered by adult nephrologists.

Patient-iPSC-Derived Kidney Organoids Show Functional Validation of a Ciliopathic Renal Phenotype and Reveal Underlying Pathogenetic Mechanisms.

Despite the increasing diagnostic rate of genomic sequencing, the genetic basis of more than 50% of heritable kidney disease remains unresolved. Kidney organoids differentiated from induced pluripotent stem cells (iPSCs) of individuals affected by inherited renal disease represent a potential, but unvalidated, platform for the functional validation of novel gene variants and investigation of underlying pathogenetic mechanisms. In this study, trio whole-exome sequencing of a prospectively identified nephronophthisis (NPHP) proband and her parents identified compound-heterozygous variants in IFT140, a gene previously associated with NPHP-related ciliopathies. IFT140 plays a key role in retrograde intraflagellar transport, but the precise downstream cellular mechanisms responsible for disease presentation remain unknown. A one-step reprogramming and gene-editing protocol was used to derive both uncorrected proband iPSCs and isogenic gene-corrected iPSCs, which were differentiated to kidney organoids. Proband organoid tubules demonstrated shortened, club-shaped primary cilia, whereas gene correction rescued this phenotype. Differential expression analysis of epithelial cells isolated from organoids suggested downregulation of genes associated with apicobasal polarity, cell-cell junctions, and dynein motor assembly in proband epithelial cells. Matrigel cyst cultures confirmed a polarization defect in proband versus gene-corrected renal epithelium. As such, this study represents a "proof of concept" for using proband-derived iPSCs to model renal disease and illustrates dysfunctional cellular pathways beyond the primary cilium in the setting of IFT140 mutations, which are established for other NPHP genotypes.

Disseminated cerebral toxoplasmosis in a patient with chronic lymphocytic leukemia.

Infections are one of the most common causes of mortality in immunocompromised patients. In patients diagnosed with hematologic malignancies, treatment with stem cell transplants (SCT) or T-cell suppressing chemotherapy increases the risk of central nervous system (CNS) infections, of which toxoplasmosis is the most common. We report the case of a 63 year-old woman with chronic lymphocytic leukemia (CLL) that presented with gait instability and visual changes. Intracranial lesions were noted on initial neuro-imaging. A rapid decline in the patient's mental status warranted an urgent biopsy of the lesions that revealed tachyzoites consistent with toxoplasmosis. In the presence of diffuse brain lesions that lack a metastatic pattern or contrast enhancement, a common approach is to perform biopsy only after a battery of non-invasive testing. This diagnostic delay may take several days, exposing the patient to a rapidly fatal infection. This report illustrates the utility of early brain biopsy in high-risk patients with hematologic malignancies and CNS lesions.

International Registry of Patients Carrying TGFBR1 or TGFBR2 Mutations: Results of the MAC (Montalcino Aortic Consortium).

BACKGROUND: The natural history of aortic diseases in patients with TGFBR1 or TGFBR2 mutations reported by different investigators has varied greatly. In particular, the current recommendations for the timing of surgical repair of the aortic root aneurysms may be overly aggressive. METHODS AND RESULTS: The Montalcino Aortic Consortium, which includes 15 centers worldwide that specialize in heritable thoracic aortic diseases, was used to gather data on 441 patients from 228 families, with 176 cases harboring a mutation in TGBR1 and 265 in TGFBR2. Patients harboring a TGFBR1 mutation have similar survival rates (80% survival at 60 years), aortic risk (23% aortic dissection and 18% preventive aortic surgery), and prevalence of extra-aortic features (29% hypertelorism, 53% cervical arterial tortuosity, and 27% wide scars) when compared with patients harboring a TGFBR2 mutation. However, TGFBR1 males had a greater aortic risk than females, whereas TGFBR2 males and females had a similar aortic risk. Additionally, aortic root diameter prior to or at the time of type A aortic dissection tended to be smaller in patients carrying a TGFBR2 mutation and was ≤45 mm in 6 women with TGFBR2 mutations, presenting with marked systemic features and low body surface area. Aortic dissection was observed in 1.6% of pregnancies. CONCLUSIONS: Patients with TGFBR1 or TGFBR2 mutations show the same prevalence of systemic features and the same global survival. Preventive aortic surgery at a diameter of 45 mm, lowered toward 40 in females with low body surface area, TGFBR2 mutation, and severe extra-aortic features may be considered.

Sporadic and Familial Congenital Cataracts: Mutational Spectrum and New Diagnoses Using Next-Generation Sequencing.

Congenital cataracts are a significant cause of lifelong visual loss. They may be isolated or associated with microcornea, microphthalmia, anterior segment dysgenesis (ASD) and glaucoma, and there can be syndromic associations. Genetic diagnosis is challenging due to marked genetic heterogeneity. In this study, next-generation sequencing (NGS) of 32 cataract-associated genes was undertaken in 46 apparently nonsyndromic congenital cataract probands, around half sporadic and half familial cases. We identified pathogenic variants in 70% of cases, and over 68% of these were novel. In almost two-thirds (20/33) of these cases, this resulted in new information about the diagnosis and/or inheritance pattern. This included identification of: new syndromic diagnoses due to NHS or BCOR mutations; complex ocular phenotypes due to PAX6 mutations; de novo autosomal-dominant or X-linked mutations in sporadic cases; and mutations in two separate cataract genes in one family. Variants were found in the crystallin and gap junction genes, including the first report of severe microphthalmia and sclerocornea associated with a novel GJA8 mutation. Mutations were also found in rarely reported genes including MAF, VIM, MIP, and BFSP1. Targeted NGS in presumed nonsyndromic congenital cataract patients provided significant diagnostic information in both familial and sporadic cases.

Sexual history taking and sexually transmitted infection screening in patients initiating erectile dysfunction medication therapy.

BACKGROUND: Erectile dysfunction medications are being prescribed frequently; however, little is known about the amount of sexual health screening occurring in this setting. METHODS: A retrospective cohort study evaluating sexual health and sexually transmitted infection screening occurring in veterans receiving initial erectile dysfunction medication prescription was conducted. RESULTS: A total of 252 patients received initial erectile dysfunction medication prescriptions between October 1, 2009, and December 31, 2009; had at least 1 health care provider visit 12 months before the date of initial prescription; and had no documentation of previous erectile dysfunction medication use. Approximately 3% of these patients had any aspect of a sexual history recorded in the 24 months surrounding initial erectile dysfunction medication prescription. Sexually transmitted infection screening was 9.9% for syphilis, 4.8% for HIV, and 4.3% for gonorrhea/chlamydia before prescription, with only a slight increase in HIV screening after prescription. CONCLUSIONS: Minimal sexual health assessment is being performed during the time surrounding initial prescription of erectile dysfunction medication. Further work needs to evaluate patient and provider barriers to basic elements of sexual health care, such as taking sexual histories or screening for sexually transmitted infections.

In-frame mutations in exon 1 of SKI cause dominant Shprintzen-Goldberg syndrome.

Shprintzen-Goldberg syndrome (SGS) is characterized by severe marfanoid habitus, intellectual disability, camptodactyly, typical facial dysmorphism, and craniosynostosis. Using family-based exome sequencing, we identified a dominantly inherited heterozygous in-frame deletion in exon 1 of SKI. Direct sequencing of SKI further identified one overlapping heterozygous in-frame deletion and ten heterozygous missense mutations affecting recurrent residues in 18 of the 19 individuals screened for SGS; these individuals included one family affected by somatic mosaicism. All mutations were located in a restricted area of exon 1, within the R-SMAD binding domain of SKI. No mutation was found in a cohort of 11 individuals with other marfanoid-craniosynostosis phenotypes. The interaction between SKI and Smad2/3 and Smad 4 regulates TGF-ß signaling, and the pattern of anomalies in Ski-deficient mice corresponds to the clinical manifestations of SGS. These findings define SGS as a member of the family of diseases associated with the TGF-ß-signaling pathway.

Detection of thirty novel FBN1 mutations in patients with Marfan syndrome or a related fibrillinopathy.

Marfan syndrome (MFS) is a disorder of the extracellular matrix caused by mutations in the gene encoding fibrillin-1 (FBN1). Recent studies have illustrated the variability in disease severity and clinical manifestations of MFS. Useful genotype-phenotype correlations have been slow to emerge. We screened 57 unrelated patients with MFS or a Marfan-like phenotype using a combination of SSCP and/or DHPLC. We detected 49 different FBN1 mutations, 30 (62%) of which were novel. The mutations comprised 38 substitutions (78%), 10 deletions (20%), and one duplication (2%). There were 28 missense (57%), nine frameshift (18%), eight splice site (16%), and four nonsense mutations (8 %). Genotype-phenotype analysis revealed that patients with an identified FBN1 mutation were more likely to have ectopia lentis and cardiovascular complications compared to those without an identifiable mutation (relative risks of 4.6 and 1.9, respectively). Ectopia lentis was also found to be more prevalent in patients whose mutations involved a cysteine substitution (relative risk 1.6) and less prevalent in those with premature termination mutations (relative risk 0.4). In our hands, we achieved 93% mutation detection for DHPLC analysis of patients who fulfilled the Ghent criteria. Further analysis of detailed clinical information and mutation data may help to anticipate the clinical consequences of specific FBN1 mutations.

Segregation of a novel FBN1 gene mutation, G1796E, with kyphoscoliosis and radiographic evidence of vertebral dysplasia in three generations.

Skeletal and spinal radiographic findings are described in five individuals of a three-generation kindred with kyphoscoliosis. The affected individuals have a novel FBN1 gene mutation, G1796E. To our knowledge, this is the first report of a family with an FBN1 gene mutation cosegregating with an unusual autosomal dominant progressive kyphoscoliosis of variable severity, together with radiological abnormalities of the spine, and some skeletal but no ocular or cardiac manifestations of Marfan syndrome. This previously undescribed phenotype represents yet another in the widening spectrum of fibrillinopathies caused by an FBN1 gene mutation.