Unaffected Carriers Research Articles

Abstract CT065: A phase Ib biomarker trial of naproxen in patients at risk for DNA mismatch repair deficient colorectal cancer

Abstract Background: Patients diagnosed with Lynch Syndrome (LS) have an approximately 70% lifetime risk of colorectal cancer (CRC) due to the presence of germline mutations in the mismatch repair (MMR) genes. Cyclooxygenases (COX) are key enzymes in the metabolism of Prostaglandins (PGs) being COX-2 induced at sites of inflammation as well as in ~85% of CRC and 50% of premalignant adenomas. Non-steroidal anti-inflammatory drugs (NSAIDs) such as Aspirin and Naproxen exert their therapeutic effects through the inhibition of both COX-1 and COX-2, which causes a reduction in PGs. However, other known non-canonical effects include inhibition of cell growth, induction of cell cycle arrest, and apoptosis. Aspirin has demonstrated chemopreventive properties in LS patients at high doses. Naproxen is widely used for the treatment of pain with an excellent safety profile. In addition, pre-clinical in vivo data using a genetically-engineered mouse model of Lynch Syndrome (Villin-Cre;Msh2LoxP/LoxP) has demonstrated that Naproxen is the most effective NSAID in preventing colorectal tumors and has shown to be superior to Aspirin. The present clinical trial was designed to assess the safety and tolerability of long-term chemoprevention with Naproxen in LS and also to discover novel biomarkers of drug activity. Methods: LS patients at 4 participating sites (The University of Texas MD Anderson Cancer Center, Dana Farber Cancer Institute, The University of Michigan Comprehensive Cancer Center, and Huntsman Cancer Institute) were randomly assigned to Naproxen 440 mg, 220 mg, or placebo once daily for 6 months. To determine the safety profile and tolerability of Naproxen, adverse events (AEs) were reported using CTCAE V4.03. To assess the activity of the drug intervention we measured Prostaglandin E2 (PGE2) levels in normal colorectal mucosa, its metabolite in urine (PGE-M), levels of Naproxen in plasma and colorectal mucosa at baseline and 6 months after treatment. Response to treatment was defined as 30% reduction in PGE2 levels. Results: A total of 86 patients were registered to this study, 28 randomized to Placebo, 25 to Naproxen 440 mg, and 27 to Naproxen 220 mg. Mean age was 44.6 years, 64% of the patients were females, 53% were unaffected carriers, and MLH1 and MSH2 were the most frequently mutated genes. Fifty-eight completed the study (67%). A total of 183 AEs were recorded in 61 patients, 77% were unrelated or unlikely related to the treatment, only 8 were reported as grade 3 AEs and none of these were related to Naproxen. In the group that received Naproxen at 440 mg, the levels of Naproxen in plasma and normal colorectal mucosa were the highest and the levels of PGE2 and PGE-M were significantly lower when compared to patients in the Placebo arm (P=0.027). In addition, the response rate was the highest among patients receiving Naproxen at 440 mg daily compared to Naproxen at 220 mg and Placebo (87.5% vs 75% vs 13%, respectively). Conclusions: The tolerance and safety of long-term chemoprevention with Naproxen at a dose of 440 mg for 6 months was excellent. There was evidence of decreased inflammatory activity among LS patients treated with high dose Naproxen compared to Placebo. Biomarker studies to discover novel non-canonical effects of Naproxen via modulation of miRNA and mRNA profiles using next-generation sequencing approaches are currently ongoing. Citation Format: Laura Reyes Uribe, Ramona Lin, Elena M. Stoffel, N. Jewel Samadder, Patrick Lynch, Priyanka Kanth, Ginger Milne, Lawrence J. Marnett, Valerie Sepeda, Diane D Liu, Y. Nancy You, Lana A. Vornik, J. Jack Lee, Ellen Richmond, Asad Umar, Marjorie Perloff, Steven M. Lipkin, Powel H. Brown, Eduardo Vilar-Sanchez. A phase Ib biomarker trial of naproxen in patients at risk for DNA mismatch repair deficient colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr CT065.

Different Patterns of Risk Reducing Decisions in Affected or Unaffected BRCA Pathogenic Variant Carriers.

PurposeThe purpose of this study was to investigate decision patterns to reduce the risks of BRCArelated breast and gynecologic cancers in carriers of BRCA pathogenic variants. We found a change in risk-reducing (RR) management patterns after December 2012, when the National Health Insurance System (NHIS) of Korea began to pay for BRCA testing and riskreducing salpingo-oophorectomy (RRSO) in pathogenic-variant carriers.Materials and MethodsThe study group consisted of 992 patients, including 705 with breast cancer (BC), 23 with ovarian cancer (OC), 10 with both, and 254 relatives of high-risk patients who underwent BRCA testing at the National Cancer Center of Korea from January 2008 to December 2016.We analyzed patterns of and factors in RR management.ResultsOf the 992 patients, 220 (22.2%) were carriers of BRCA pathogenic variants. About 92.3% (203/220) had a family history of BC and/or OC,which significantly differed between BRCA1 and BRCA2 carriers (p < 0.001). All 41 male carriers chose surveillance. Of the 179 female carriers, 59 of the 83 carriers (71.1%) with BC and the 39 of 79 unaffected carriers (49.4%) underwent RR management. None of the carriers affected with OC underwent RR management. Of the management types, RRSO had the highest rate (42.5%) of patient choice. The rate of RR surgery was significantly higher after 2013 than before 2013 (46.3% [74/160] vs. 31.6% [6/19], p < 0.001).ConclusionRRSO was the preferred management for carriers of BRCA pathogenic variants. The most important factors in treatment choice were NHIS reimbursement and/or the severity of illness.

SCN5A (NaV1.5) Variant Functional Perturbation and Clinical Presentation: Variants of a Certain Significance.

Accurately predicting the impact of rare nonsynonymous variants on disease risk is an important goal in precision medicine. Variants in the cardiac sodium channel SCN5A (protein NaV1.5; voltage-dependent cardiac Na+ channel) are associated with multiple arrhythmia disorders, including Brugada syndrome and long QT syndrome. Rare SCN5A variants also occur in ≈1% of unaffected individuals. We hypothesized that in vitro electrophysiological functional parameters explain a statistically significant portion of the variability in disease penetrance. From a comprehensive literature review, we quantified the number of carriers presenting with and without disease for 1712 reported SCN5A variants. For 356 variants, data were also available for 5 NaV1.5 electrophysiological parameters: peak current, late/persistent current, steady-state V1/2 of activation and inactivation, and recovery from inactivation. We found that peak and late current significantly associate with Brugada syndrome (P<0.001; ρ=-0.44; Spearman rank test) and long QT syndrome disease penetrance (P<0.001; ρ=0.37). Steady-state V1/2 activation and recovery from inactivation associate significantly with Brugada syndrome and long QT syndrome penetrance, respectively. Continuous estimates of disease penetrance align with the current American College of Medical Genetics classification paradigm. NaV1.5 in vitro electrophysiological parameters are correlated with Brugada syndrome and long QT syndrome disease risk. Our data emphasize the value of in vitro electrophysiological characterization and incorporating counts of affected and unaffected carriers to aid variant classification. This quantitative analysis of the electrophysiological literature should aid the interpretation of NaV1.5 variant electrophysiological abnormalities and help improve NaV1.5 variant classification.

Parent-of-origin effect of hypomorphic pathogenic variants and somatic mosaicism impact on phenotypic expression of retinoblastoma.

Retinoblastoma is the most common eye cancer in children. Numerous families have been described displaying reduced penetrance and expressivity. An extensive molecular characterization of seven families led us to characterize the two main mechanisms impacting on phenotypic expression, as follows: (i) mosaicism of amorphic pathogenic variants; and (ii) parent-of-origin-effect of hypomorphic pathogenic variants. Somatic mosaicism for RB1 splicing variants (c.1960+5G>C and c.2106+2T>C), leading to a complete loss of function was demonstrated by high-depth NGS in two families. In both cases, the healthy carrier parent (one with retinoma) showed a variant frequency lower than that expected for a heterozygous individual, indicating a 56-60% mosaicism level. Previous evidences of a ~3-fold excess of RB1 maternal canonical transcript led us to hypothesize that this differential allelic expression could influence phenotypic outcome in families at risk for RB onset. Accordingly, in five families, we identified a higher tumor risk associated with paternally inherited hypomorphic pathogenic variants, namely a deletion resulting in the loss of 37 amino acids at the N-terminus (c.608-16_608del), an exonic substitution with a "leaky" splicing effect (c.1331A>G), a partially deleterious substitution (c.1981C>T) and a truncating C-terminal variant (c.2663+2T>C). The identification of these mechanisms changes the genetic/prenatal counseling and the clinical management of families, indicating a higher recurrence risk when the hypomorphic pathogenic variant is inherited from the father, and suggesting the need for second tumor surveillance in unaffected carriers at risk of developing adult-onset cancer such as osteosarcoma or leiomyosarcoma.

Clinical variability and onset age modifiers in an extended Belgian GRN founder family.

We previously reported a granulin (GRN) null mutation, originating from a common founder, in multiple Belgian families with frontotemporal dementia. Here, we used data of a 10-year follow-up study to describe in detail the clinical heterogeneity observed in this extended founder pedigree. We identified 85 patients and 40 unaffected mutation carriers, belonging to 29 branches of the founder pedigree. Most patients (74.4%) were diagnosed with frontotemporal dementia, while others had a clinical diagnosis of unspecified dementia, Alzheimer's dementia or Parkinson's disease. The observed clinical heterogeneity can guide clinical diagnosis, genetic testing, and counseling of mutation carriers. Onset of initial symptomatology is highly variable, ranging from age 45 to 80years. Analysis of known modifiers, suggested effects of GRN rs5848, microtubule-associated protein tau H1/H2, and chromosome 9 open reading frame 72 G4C2 repeat length on onset age but explained only a minor fraction of the variability. Contrary, the extended GRN founder family is a valuable source for identifying other onset age modifiers based on exome or genome sequences. These modifiers might be interesting targets for developing disease-modifying therapies.

Unusual AIP mutation and phenocopy in the family of a young patient with acromegalic gigantism.

SummaryEarly-onset acromegaly causing gigantism is often associated with aryl-hydrocarbon-interacting receptor protein (AIP) mutation, especially if there is a positive family history. A15y male presented with tiredness and visual problems. He was 201 cm tall with a span of 217 cm. He had typical facial features of acromegaly, elevated IGF-1, secondary hypogonadism and a large macroadenoma. His paternal aunt had a history of acromegaly presenting at the age of 35 years. Following transsphenoidal surgery, his IGF-1 normalized and clinical symptoms improved. He was found to have a novel AIP mutation destroying the stop codon c.991T>C; p.*331R. Unexpectedly, his father and paternal aunt were negative for this mutation while his mother and older sister were unaffected carriers, suggesting that his aunt represents a phenocopy.Learning points:Typical presentation for a patient with AIP mutation with excess growth and eunuchoid proportions.Unusual, previously not described AIP variant with loss of the stop codon.Phenocopy may occur in families with a disease-causing germline mutation.

Evidence for genetic anticipation in vonHippel-Lindau syndrome

Backgroundvon Hippel-Lindau (vHL) syndrome is a rare autosomal-dominant disorder that confers a lifelong risk for developing both benign and malignant tumours in multiple organs. Recent evidence suggests that vHL may...

Bioactivity and gene expression profiles of hiPSC-generated retinal ganglion cells in MT-ND4 mutated Leber's hereditary optic neuropathy

Leber’s hereditary optic neuropathy (LHON) is the maternally inherited mitochondrial disease caused by homoplasmic mutations in mitochondrial electron transport chain Complex I subunit genes. The mechanism of its incomplete penetrance is still largely unclear. In this study, we created the patient-specific human induced pluripotent stem cells (hiPSCs) from MT-ND4 mutated LHON-affected patient, asymptomatic mutation carrier and healthy control, and differentiated them into retinal ganglion cells (RGCs). We found the defective neurite outgrowth in affected RGCs, but not in the carrier RGCs which had significant expression of SNCG gene. We observed enhanced mitochondrial biogenesis in affected and carrier derived RGCs. Surprisingly, we observed increased NADH dehydrogenase enzymatic activity of Complex I in hiPSC-derived RGCs of asymptomatic carrier, but not of the affected patient. LHON mutation substantially decreased basal respiration in both affected and unaffected carrier hiPSCs, and had the same effect on spare respiratory capacity, which ensures normal function of mitochondria in conditions of increased energy demand or environmental stress. The expression of antioxidant enzyme catalase was decreased in affected and carrier patient hiPSC-derived RGCs as compared to the healthy control, which might indicate to higher oxidative stress-enriched environment in the LHON-specific RGCs. Microarray profiling demonstrated enhanced expression of cell cycle machinery and downregulation of neuronal specific genes.

CXorf56, a dendritic neuronal protein, identified as a new candidate gene for X-linked intellectual disability.

Intellectual disability (ID) comprises a large group of heterogeneous disorders, often without a known molecular cause. X-linked ID accounts for 5-10% of male ID cases. We investigated a large, three-generation family with mild ID and behavior problems in five males and one female, with a segregation suggestive for X-linked inheritance. Linkage analysis mapped a disease locus to a 7.6 Mb candidate region on the X-chromosome (LOD score 3.3). Whole-genome sequencing identified a 2 bp insertion in exon 2 of the chromosome X open reading frame 56 gene (CXorf56), resulting in a premature stop codon. This insertion was present in all intellectually impaired individuals and carrier females. Additionally, X-inactivation status showed skewed methylation patterns favoring the inactivation of the mutated allele in the unaffected carrier females. We demonstrate that the insertion leads to nonsense-mediated decay and that CXorf56 mRNA expression is reduced in the impaired males and female. In murine brain slices and primary hippocampal neuronal cultures, CXorf56 protein was present and localized in the nucleus, cell soma, dendrites, and dendritic spines. Although no other families have been identified with pathogenic variants in CXorf56, these results suggest that CXorf56 is the causative gene in this family, and thus a novel candidate gene for X-linked ID with behavior problems.

The association between smoking and cancer incidence in BRCA1 and BRCA2 mutation carriers.

Tobacco smoke is an established carcinogen, but the association between tobacco smoking and cancer risk in BRCA mutation carriers is not clear. The aim of this study was to evaluate prospectively the association between tobacco smoking and cancer incidence in a cohort of BRCA1 and BRCA2 mutation carriers. The study population consisted of unaffected BRCA mutation carriers. Information on lifestyle including smoking histories, reproductive factors, and past medical histories was obtained through questionnaires. Incident cancers were updated biennially via follow-up questionnaires. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using time-dependent Cox regression models. There were 700 incident cancers diagnosed over 26,711 person-years of follow-up. The most frequent cancers seen in BRCA mutation carriers were breast (n = 428; 61%) and ovarian (n = 109; 15%) cancer. Compared to nonsmokers, (ever) smoking was associated with a modest increased risk of all cancers combined (HR = 1.17; 95%CI 1.01-1.37). Women in the highest group of total pack-years (4.3-9.8) had an increased risk of developing any cancer (HR = 1.27; 95%CI 1.04-1.56), breast cancer (HR = 1.33, 95%CI 1.02-1.75), and ovarian cancer (HR = 1.68; 95%CI 1.06-2.67) compared to never smokers. The associations between tobacco smoking and cancer did not differ by BRCA mutation type or by age at diagnosis. This prospective study suggests that tobacco smoking is associated with a modest increase in the risks of breast and ovarian cancer among women with BRCA1 or BRCA2 mutation.

Target-enriched sequencing of chromosome 17q21.31 in sporadic tauopathies reveals no candidate variants

The main genetic risk factors for progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD) are located at chromosome 17q21.31. The identification of risk H1 subhaplotypes suggests that disease-specific variants can be identified by resequencing the 17q21.31 region (1.4 Mb) in carriers of risk H1 subhaplotypes. We hypothesized that PSP/CBD H1 subhaplotype carriers could have undergone a mutational event absent among unaffected carriers leading to the disease risk. We performed this strategy in definite PSP subjects, definite CBD subjects, and healthy controls and tried to replicate the findings in a larger PSP/CBD case-control series. In the resequencing process, 40 candidate variants were identified, but an association between PSP and rs76970862 was replicated only using an unadjusted model. Gene expression association analysis of this variant suggested no potential functional effect. Although our results failed to identify disease-associated variants, it is still possible that the risk of PSP/CBD at chromosome 17 is driven by rare variants, even in PSP/CBD H1 cases or variants located outside the capture regions.

Expansion and further delineation of the SETD5 phenotype leading to global developmental delay, variable dysmorphic features, and reduced penetrance.

Diagnostic exome sequencing (DES) has aided delineation of the phenotypic spectrum of rare genetic etiologies of intellectual disability (ID). A SET domain containing 5 gene (SETD5) phenotype of ID and dysmorphic features has been previously described in relation to patients with 3p25.3 deletions and in a few individuals with de novo sequence alterations. Herein, we present additional patients with pathogenic SETD5 sequence alterations. The majority of patients in this cohort and previously reported have developmental delay, behavioral/psychiatric issues, and variable hand and skeletal abnormalities. We also present an apparently unaffected carrier mother of an affected individual and a carrier mother with normal intelligence and affected twin sons. We suggest that the phenotype of SETD5 is more complex and variable than previously presented. Therefore, many features and presentations need to be considered when evaluating a patient for SETD5 alterations through DES.

Delay in State Adoption of Newborn Screening Tests.

* Abbreviations: CCHD — : critical congenital heart disease MPS I — : mucopolysaccharidosis I RUSP — : Recommended Uniform Screening Panel SACHDNC — : Secretary’s Advisory Committee on Heritable Disorders in Newborns and Children SCID — : severe combined immunodeficiency Newborn screening is a critical public health intervention. Every year, thousands of newborns are diagnosed with a disease via newborn screening; this allows for timely treatment that decreases morbidity and mortality and generates considerable health care savings. In 2005, the Secretary’s Advisory Committee on Heritable Disorders in Newborns and Children (SACHDNC) proposed the Recommended Uniform Screening Panel (RUSP), consisting then of 29 core conditions to adopt as the national newborn screening standard. The RUSP’s core conditions and any future additions had to meet 3 inclusion criteria: the disorder must be detectable within 48 hours of birth, the screening test must be sensitive and specific, and early detection must enable early treatment to secure proven benefit.1 Adding a condition to the RUSP is a rigorous, multistep process. Petitioners must write a report to the SACHDNC, presenting an overview of the condition, treatment efficacy and availability, validation of a laboratory test with available follow-up confirmatory testing, and a prospective population pilot study. Meeting these criteria can prove challenging. For example, the addition of mucopolysaccharidosis I (MPS I) and adrenoleukodystrophy were delayed because both diseases have a relatively unaffected carrier population, raising concern as to whether screening would pick up carrier patients. The SACHDNC then makes recommendations to the Secretary on the basis of an independent external evaluation regarding both inclusion criteria and feasibility. States are not legally bound by the … Address correspondence to Stephanie R. Morain, MPH, PhD, Center for Medical Ethics and Health Policy, Baylor College of Medicine, 1 Baylor Plaza, Suite 310D, Houston, TX 77030. E-mail: stephanie.morain{at}bcm.edu

Developmental Outcomes of Children Exposed to Maternal Sickle Cell Disease (SCD)

▪ BACKGROUNDPregnant women with SCD have an increased risk of both maternal and fetal complications, including preeclampsia, venous thromboembolism, and cardiomyopathy, as well as an increased risk of intrauterine growth restriction, preterm birth, low birth weight, and fetal demise. While in general children with a history of intrauterine growth restriction are at risk for abnormal neurodevelopment as well as later obesity and metabolic syndrome, the long-term developmental outcomes of children without SCD but exposed to maternal SCD are unknown. Better data about the long-term developmental outcome for children of mothers with SCD will provide guidance about the utility of disease modifying therapy during pregnancy. The objective of this study is to explore outcomes for children born to mothers with SCD using data from the Boston Birth Cohort (BBC). METHODSThe BBC is a prospective birth cohort established in 1998 at the Boston Medical Center (BMC) that recruits preterm cases (born at less than 37 weeks gestation) and full term controls. The BBC enrolls predominantly urban, low-income minority mothers and their children 24-72 hours after delivery at the BMC and follows the children from birth up to age 21 years. Data is collected on maternal preconception medical conditions, pregnancy complications, and pregnancy exposures through structured interviews at the time of enrollment and medical record extraction. Data on child development is collected from medical records and structured interviews performed by trained study staff at their scheduled pediatric appointments. Approximately 38% of study participants self-identify as black/African American, 22% as Hispanic, 19% as Haitian, and 8.5% as white. From maternal electronic medical record data capturing 147,827 emergency room and outpatient visits contributed by 5,972 subjects, we identified all women with ICD-9-CM codes for sickle cell disease (282.60-64, 282.68, 282.69, 282.41, 282.42) and probable (two or more 282.62 codes) sickle cell anemia. We then linked maternal and child data on the basis of a unique family-level study ID. Information on child development was obtained from electronic medical record data, based on the presence of relevant ICD-9-CM hospital diagnosis codes from pediatric outpatient, inpatient, and emergency room visits. RESULTSWe identified 93 women who had at least one of the ICD-9 codes for SCD. For this report we have included only those forty-one women who were coded at least twice with a 282.62 diagnosis (Hemoglobin SS disease with crisis). Six (15%) had poor fetal growth during their pregnancy, while eight (20%) were diagnosed with preeclampsia or antepartum hypertension. Among these mothers with available questionnaire and medical record extraction data (n = 38), 7 (18%) delivered their children before 37 weeks gestation, and 6 (16%) had children weighing less than 2500 grams at birth. Twenty mothers had children who received pediatric care at the Boston Medical Center, with ages ranging from 2 to 9 years of age; one was diagnosed with SCA, while 19 are unaffected carriers. Among the 19 children without SCD with available follow-up data, 5 (26%) carried a diagnosis code of overweight/obesity; their mothers were seen for an average of 73 medical visits (SD 50) during their pregnancy. Five children, without any overlap with the children diagnosed with obesity, were diagnosed with failure to thrive; while not statistically significantly different, their mothers had fewer medical encounters (mean 55, SD 37). Five children were diagnosed with delayed milestones, two of whom were late preterm (35 and 33 weeks gestation); two of these children were diagnosed with obesity and two with failure to thrive. DISCUSSIONThis exploratory, descriptive study represents the first data on long-term outcomes of children without SCD who were exposed to maternal SCD in utero . While we are limited by small sample size, finding that 26% of children born to mothers with SCD have developmental delay is a significant concern. This compares to the overall cohort where 12% of control children and 39% of preterm cases have been found to have developmental delay. Future studies will include medical record review of mothers to identify additional mothers with confirmed SCD in the cohort and exploration of additional predictors of these concerning outcomes. [Display omitted] DisclosuresLanzkron:Prolong: Research Funding; HRSA: Research Funding; Bayer: Research Funding; Global Blood Therapeutics: Research Funding; Pfizer: Research Funding; PCORI: Research Funding.

The first Sri Lankan family with Dent disease-1 due to a pathogenic variant in the CLCN5 gene: a case report

BackgroundDent disease-1 is a rare X-linked recessive renal tubular disorder caused by pathogenic variants in the chloride voltage-gated channel 5 (CLCN5) gene. It is characterized by low-molecular-weight proteinuria, hypercalciuria, nephrocalcinosis, nephrolithiasis and progressive renal failure. This is the first report of a CLCN5 pathogenic variant in a Dent disease-1 family of Sri Lankan origin, and it highlights the value of genetic evaluation in children with refractory proteinuria.Case presentationA 2-year-old boy with non-nephrotic range proteinuria was referred for evaluation. His maternally related 24-year-old uncle had been investigated for similar features at the age of 14 years and his renal histology had shown few sclerosed glomeruli. He remained asymptomatic apart from proteinuria. Biochemical investigation of the child showed β-2 microglobulinuria and hypercalciuria. After providing pre-test counseling and obtaining written informed consent, the child, his mother and maternal uncle underwent genetic testing for confirmation of the clinically suspected diagnosis of Dent disease-1. Both the child and his maternal uncle were found to be hemizygous for a nonsense pathogenic variant in exon 9 of the CLCN5 gene [NM_000084.4; c.1399C>T; rs797044811] which results in a stop codon at residue 467, leading to a truncated non-functional protein [NP_000075.1; p.R467X]. His mother was confirmed to be an unaffected heterozygous carrier for the same variant. Following confirmation of the diagnosis our patient was started on thiazide diuretics and potassium citrate.ConclusionsEven though the typical phenotype of Dent disease-1 often enables a clinical diagnosis to be made, less severe sub-clinical cases may go undiagnosed. The underlying diagnosis may be missed especially in children who are treated for non-minimal change nephrotic syndrome with steroids. This case highlights the need for tubular proteinuria to be considered in the differential diagnosis of children with refractory proteinuria and for appropriate genetic evaluation to be done to confirm the precise underlying diagnosis in such cases.

Factor H Competitor Generated by Gene Conversion Events Associates with Atypical Hemolytic Uremic Syndrome.

Atypical hemolytic uremic syndrome (aHUS), a rare form of thrombotic microangiopathy caused by complement pathogenic variants, mainly affects the kidney microvasculature. A retrospective genetic analysis in our aHUS cohort (n=513) using multiple ligation probe amplification uncovered nine unrelated patients carrying a genetic abnormality in the complement factor H related 1 gene (CFHR1) that originates by recurrent gene conversion events between the CFH and CFHR1 genes. The novel CFHR1 mutants encode an FHR-1 protein with two amino acid substitutions, L290S and A296V, converting the FHR-1 C terminus into that of factor H (FH). Next-generation massive-parallel DNA sequencing (NGS) analysis did not detect these genetic abnormalities. In addition to the CFHR1 mutant, six patients carried the previously uncharacterized CFH-411T variant. In functional analyses, the mutant FHR-1 protein strongly competed the binding of FH to cell surfaces, impairing complement regulation, whereas the CFH-411T polymorphism lacked functional consequences. Carriers of the CFHR1 mutation presented with severe aHUS during adulthood; 57% of affected women in this cohort presented during the postpartum period. Analyses in patients and unaffected carriers showed that FH plasma levels determined by the nonmutated chromosome modulate disease penetrance. Crucially, in the activated endothelial (HMEC-1) cell assay, reduced FH plasma levels produced by the nonmutated chromosome correlated inversely with impairment of complement regulation, measured as C5b-9 deposition. Our data advance understanding of the genetic complexities underlying aHUS, illustrate the importance of performing functional analysis, and support the use of complementary assays to disclose genetic abnormalities not revealed by current NGS analysis.

The expected benefit of preventive mastectomy on breast cancer incidence and mortality in BRCA mutation carriers, by age at mastectomy.

Preventive breast surgery is offered to unaffected BRCA mutation carriers to prevent breast cancer incidence and mortality. The clinical benefit of preventive mastectomy can be measured in several ways, including extension of life expectancy (mean years of life gained) and by estimating the probability of surviving until age 80. We sought to estimate the expected benefit of a preventive mastectomy at various ages, using these indices of mortality, by simulating hypothetical cohorts of women. The age-specific annual risks of developing breast cancer were used to estimate the actuarial risk of developing breast cancer by age 80 for women with a BRCA1 or BRCA2 mutation. The probability of developing breast cancer before age 80 was then modified to include competing causes of death, including from ovarian cancer. The mortality rate from breast cancer after a diagnosis of breast cancer was set at 2% annually for the first 10 years and then 1% annually for years ten to twenty. The incidence rate and mortality rate from ovarian cancer were based on published literature. We assumed that preventive mastectomy was associated with complete protection against subsequent breast cancer. A series of simulations was conducted to evaluate the reduction in the probability of death (from all causes) until age 80, according to the age at mastectomy. The actuarial risk of developing breast cancer until age 80 was estimated to be 70.8%. The actual risk (incorporating competing risks) was 64.0%. The probability of being alive at age 80 by having a mastectomy at age 25 increased by 8.7% (from 42.7 to 51.3%). The estimated benefit declined with age at mastectomy; for surgery done at age 50 the improvement in survival to age 80 was much more modest (2.8% at age 80, from 42.7 to 45.5%). Among BRCA mutation carriers, the mortality benefit of preventive mastectomy at age 25 is substantial, but the expected benefit declines rapidly with increasing age at surgery.

Huntington Disease: The Complexities of Making and Disclosing a Clinical Diagnosis After Premanifest Genetic Testing.

The management of patients and families affected by Huntington disease (HD) is complicated by several factors, both practical and ethical. It can be difficult to determine the onset of clinically manifest HD (mHD). In addition, it can be challenging to decide when to disclose the diagnosis to the affected individual. Firstly, the features of HD, an incurable, inherited, neurocognitive disorder that often manifests in young adulthood, influence how the person presents and accepts a diagnosis. Secondly, a positive genetic test for HD may result in a genetic diagnosis, sometimes years before the development of clinical features and the diagnosis of mHD. Thirdly, observational studies of unaffected gene expansion carriers documented HD manifestations up to 10 years before the typical presentation for diagnosis. These developments may permit earlier genetic diagnosis and information regarding the patient’s likely status with respect to the development of clinical disease. Making the genetic diagnosis of HD and providing information regarding disease status, earlier rather than later, respects the person’s right to know and preserves honesty in the doctor/patient relationship. Conversely, delaying the diagnosis respects the right not to know, avoids potential discrimination, and permits the person to live a “normal” life for longer, in the context of a disease without cure. This discussion has implications for other inherited and neurocognitive disorders.

Huntington Disease: The Complexities of Making and Disclosing a Clinical Diagnosis After Premanifest Genetic Testing

The management of patients and families affected by Huntington disease (HD) is complicated by several factors, both practical and ethical. It can be difficult to determine the onset of clinically manifest HD (mHD). In addition, it can be challenging to decide when to disclose the diagnosis to the affected individual. Firstly, the features of HD, an incurable, inherited, neurocognitive disorder that often manifests in young adulthood, influence how the person presents and accepts a diagnosis. Secondly, a positive genetic test for HD may result in a genetic diagnosis, sometimes years before the development of clinical features and the diagnosis of mHD. Thirdly, observational studies of unaffected gene expansion carriers documented HD manifestations up to 10 years before the typical presentation for diagnosis. These developments may permit earlier genetic diagnosis and information regarding the patient’s likely status with respect to the development of clinical disease. Making the genetic diagnosis of HD and providing information regarding disease status, earlier rather than later, respects the person’s right to know and preserves honesty in the doctor/patient relationship. Conversely, delaying the diagnosis respects the right not to know, avoids potential discrimination, and permits the person to live a ‘‘normal’’ life for longer, in the context of a disease without cure. This discussion has implications for other inherited and neurocognitive disorders.

Ovarian Aging in Women With BRCA Germline Mutations.

Recent clinical and laboratory studies suggested that women with BRCA mutations have lower ovarian reserve and their primordial follicle oocytes may be more prone to DNA damage; however, direct proof is lacking. To determine whether women with germline BRCA mutations have reduced primordial follicle reserve and increased oocyte DNA damage. A comparative laboratory study of ovarian tissue obtained from unaffected BRCA mutation carriers (BMCs) vs age-matched organ donor cadavers. Two academic centers. Of the 230 ovarian specimens from BMCs, 18 met the study inclusion criteria. Healthy ovaries from 12 organ donor cadavers served as controls. Histology and immunohistochemical analysis on paraffin-embedded ovarian sections. Primordial follicle density and the percentage of DNA double-strand break (DSB)-positive primordial follicle oocytes. Ovaries from BMCs had significantly lower primordial follicle densities than those of controls (11.2 ± 2.0 vs 44.2 ± 6.2 follicles/mm3; P = 0.0002). BRCA mutations were associated with increased DNA DSBs in primordial follicle oocytes (62% ± 5.2% vs 36% ± 3.4%; P = 0.0005). In subgroup analyses, both BRCA1 and BRCA2 mutations were associated with lower primordial follicle density (P = 0.0001 and 0.0030, respectively), and BRCA1 mutations were associated with higher DNA DSBs (P = 0.0003) than controls. The rates of follicle decline (R2 = 0.74; P = 0.0001) and DNA DSB accumulation (R2 = 0.70; P = 0.0001) appeared to be accelerated, particularly in primordial follicle oocytes of BMCs over age 30 years. We provide direct evidence of diminished ovarian reserve as well as accelerated primordial follicle loss and oocyte DNA damage in women with BRCA mutations. These findings may further our understanding of ovarian aging, and be useful when counseling BMCs.