scholarly journals Clinical and genetic variability in children with partial albinism

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Patrick Campbell ◽  
Jamie M. Ellingford ◽  
Neil R. A. Parry ◽  
Tracy Fletcher ◽  
Simon C. Ramsden ◽  
...  

Abstract Individuals who have ocular features of albinism and skin pigmentation in keeping with their familial background present a considerable diagnostic challenge. Timely diagnosis through genomic testing can help avert diagnostic odysseys and facilitates accurate genetic counselling and tailored specialist management. Here, we report the clinical and gene panel testing findings in 12 children with presumed ocular albinism. A definitive molecular diagnosis was made in 8/12 probands (67%) and a possible molecular diagnosis was identified in a further 3/12 probands (25%). TYR was the most commonly mutated gene in this cohort (75% of patients, 9/12). A disease-causing TYR haplotype comprised of two common, functional polymorphisms, TYR c.[575 C > A;1205 G > A] p.[(Ser192Tyr);(Arg402Gln)], was found to be particularly prevalent. One participant had GPR143-associated X-linked ocular albinism and another proband had biallelic variants in SLC38A8, a glutamine transporter gene associated with foveal hypoplasia and optic nerve misrouting without pigmentation defects. Intriguingly, 2/12 individuals had a single, rare, likely pathogenic variant in each of TYR and OCA2 – a significant enrichment compared to a control cohort of 4046 individuals from the 100,000 genomes project pilot dataset. Overall, our findings highlight that panel-based genetic testing is a clinically useful test with a high diagnostic yield in children with partial/ocular albinism.

2021 ◽  
Vol 22 (3) ◽  
pp. 1130
Author(s):  
Elena R. Schiff ◽  
Vijay K. Tailor ◽  
Hwei Wuen Chan ◽  
Maria Theodorou ◽  
Andrew R. Webster ◽  
...  

Biallelic pathogenic variants in solute carrier family 38 member 8, SLC38A8, cause a pan-ocular autosomal recessive condition known as foveal hypoplasia 2, FVH2, characterised by foveal hypoplasia, nystagmus and optic nerve chiasmal misrouting. Patients are often clinically diagnosed with ocular albinism, but foveal hypoplasia can occur in several other ocular disorders. Here we describe nine patients from seven families who had molecularly confirmed biallelic recessive variants in SLC38A8 identified through whole genome sequencing or targeted gene panel testing. We identified four novel sequence variants (p.(Tyr88*), p.(Trp145*), p.(Glu233Gly) and c.632+1G>A). All patients presented with foveal hypoplasia, nystagmus and reduced visual acuity; however, one patient did not exhibit any signs of chiasmal misrouting, and three patients had features of anterior segment dysgenesis. We highlight these findings in the context of 30 other families reported to date. This study reinforces the importance of obtaining a molecular diagnosis in patients whose phenotype overlap with other inherited ocular conditions, in order to support genetic counselling, clinical prognosis and family planning. We expand the spectrum of SLC38A8 mutations which will be relevant for treatment through future genetic-based therapies.


2015 ◽  
Vol 33 (28_suppl) ◽  
pp. 16-16
Author(s):  
Nimmi S. Kapoor ◽  
Lisa D. Curcio ◽  
Carlee A. Blakemore ◽  
Amy K. Bremner ◽  
Rachel E. McFarland ◽  
...  

16 Background: Recently introduced multi-gene panel testing including BRCA1 and BRCA2 genes (BRCA1/2) for hereditary cancer risk has raised concerns with the ability to detect all deleterious BRCA1/2 mutations compared to older methods of sequentially testing BRCA1/2 separately. The purpose of this study is to evaluate rates of pathogenic BRCA1/2mutations and variants of uncertain significance (VUS) between previous restricted algorithms of genetic testing and newer approaches of multi-gene testing. Methods: Data was collected retrospectively from 966 patients who underwent genetic testing at one of three sites from a single institution. Test results were compared between patients who underwent BRCA1/2testing only (limited group, n = 629) to those who underwent multi-gene testing with 5-43 cancer-related genes (panel group, n = 337). Results: Deleterious BRCA1/2 mutations were identified in 37 patients, with equivalent rates between limited and panel groups (4.0% vs 3.6%, respectively, p = 0.86). Thirty-nine patients had a BRCA1/2 VUS, with similar rates between limited and panel groups (4.5% vs 3.3%, respectively, p = 0.49). On multivariate analysis, there was no difference in detection of either BRCA1/2 mutations or VUS between both groups. Of patients undergoing panel testing, an additional 3.9% (n = 13) had non-BRCA pathogenic mutations and 13.4% (n = 45) had non-BRCA VUSs. Mutations in PALB2, CHEK2, and ATM were the most common non-BRCA mutations identified. Conclusions: Multi-gene panel testing detects pathogenic BRCA1/2 mutations at equivalent rates as limited testing and increases the diagnostic yield. Panel testing increases the VUS rate, mainly due to non-BRCA genes. Patients at risk for hereditary breast cancer can safely benefit from upfront, more efficient, multi-gene panel testing.


2017 ◽  
Vol 35 (15_suppl) ◽  
pp. 1525-1525
Author(s):  
Gregory Idos ◽  
Allison W. Kurian ◽  
Charite Nicolette Ricker ◽  
Duveen Sturgeon ◽  
Julie Culver ◽  
...  

1525 Background: Genetic testing is a powerful tool for stratifying cancer risk. Multiplex gene panel (MGP) testing allows simultaneous analysis of multiple high- and moderate- penetrance genes. However, the diagnostic yield and clinical utility of panels remain to be further delineated. Methods: A report of a fully accrued trial (N = 2000) of patients undergoing cancer-risk assessment. Patients were enrolled in a multicenter prospective cohort study where diagnostic yield and off-target mutation detection was evaluated of a 25 gene MGP comprised of APC, ATM, BARD1, BMPR1A, BRCA1, BRCA2, BRIP1, CDH1, CDK4, CDKN2A, CHEK2, EPCAM, MLH1, MSH2, MSH6, MUTYH, NBN, PALB2, PMS2, PTEN, RAD51C, RAD51D, SMAD4, STK11, TP53. Patients were enrolled if they met standard testing guidelines or were predicted to have a ≥2.5% mutation probability by validated models. Differential diagnoses (DDx) were generated after expert clinical genetics assessment, formulating up to 8 inherited cancer syndromes ranked by estimated likelihood. Results: 1998/2000 patients had reported MGP test results. Women constituted 81% of the sample, and 40% were Hispanic; 241 tested positive for at least 1 pathogenic mutation (12.1%) and 689 (34.5%) patients carried at least 1 variant of uncertain significance. The most frequently identified mutations were in BRCA1 (17%, n = 41), BRCA2 (15%, n = 36), APC (8%, n = 19), CHEK2 (7%, n = 17), ATM (7%, n = 16). 39 patients (16%) had at least 1 pathogenic mutation in a mismatch repair (MMR) gene ( MLH1, n = 10; MSH2, n = 10; MSH6, n = 8; PMS2, n = 11). 43 individuals (18%) had MUTYH mutations – 41 were monoallelic. Among 19 patients who had mutations in APC – 16 were APC I1307K. Only 65% (n = 159) of PV results were included in the DDx, with 35% (n = 86) of mutations not clinically suspected. Conclusions: In a diverse cohort, multiplex panel use increased genetic testing yield substantially: 35% carried pathogenic mutations in unsuspected genes, suggesting a significant contribution of expanded multiplex testing to clinical cancer risk assessment. The identification of off-target mutations broadens our understanding of cancer risk and genotype-phenotype correlations. Follow-up is ongoing to assess the clinical utility of multiplex gene panel testing. Clinical trial information: NCT02324062.


Genes ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 508
Author(s):  
Hwei Wuen Chan ◽  
Elena R. Schiff ◽  
Vijay K. Tailor ◽  
Samantha Malka ◽  
Magella M. Neveu ◽  
...  

Albinism encompasses a group of hereditary disorders characterized by reduced or absent ocular pigment and variable skin and/or hair involvement, with syndromic forms such as Hermansky–Pudlak syndrome and Chédiak–Higashi syndrome. Autosomal recessive oculocutaneous albinism (OCA) is phenotypically and genetically heterogenous (associated with seven genes). X-linked ocular albinism (OA) is associated with only one gene, GPR143. We report the clinical and genetic outcomes of 44 patients, from 40 unrelated families of diverse ethnicities, with query albinism presenting to the ocular genetics service at Moorfields Eye Hospital NHS Foundation Trust between November 2017 and October 2019. Thirty-six were children (≤ 16 years) with a median age of 31 months (range 2–186), and eight adults with a median age of 33 years (range 17–39); 52.3% (n = 23) were male. Genetic testing using whole genome sequencing (WGS, n = 9) or a targeted gene panel (n = 31) gave an overall diagnostic rate of 42.5% (44.4% (4/9) with WGS and 41.9% (13/31) with panel testing). Seventeen families had confirmed mutations in TYR (n = 9), OCA2, (n = 4), HPS1 (n = 1), HPS3 (n = 1), HPS6 (n = 1), and GPR143 (n = 1). Molecular diagnosis of albinism remains challenging due to factors such as missing heritability. Differential diagnoses must include SLC38A8-associated foveal hypoplasia and syndromic forms of albinism.


2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. A512-A513
Author(s):  
Carolyn Horton ◽  
Marcy Richardson ◽  
Kate Durda ◽  
Amal Yussuf ◽  
Michelle Jackson ◽  
...  

Abstract Background: Pheochromocytomas (PCCs) and paragangliomas (PGLs) (PPGLs) are a genetically heterogeneous entity, with roughly 25-40% of cases found to harbor a pathogenic or likely pathogenic germline alteration. Existing practice guidelines advocating for the use of a sequential gene testing strategy to identify individuals with hereditary PPGL are driven by the presence of specific clinical features and predate the routine use of multigene panel testing (MGPT). Here we describe results of MGPT for hereditary PPGL in a clinically and ancestrally diverse cohort from a diagnostic laboratory. Methods: Demographic and clinical information of individuals undergoing targeted MGPT for hereditary PPGL were collected from test requisition forms and supporting clinical documents provided by the ordering clinician and retrospectively reviewed. Individuals underwent MGPT of 10-12 genes depending on test order date. From August 2013 through May 2015, 560 individuals had targeted MGPT that included 10 genes (NF1, MAX, SDHA/B/C/D/AF2, RET, TMEM127, and VHL), and from May 2015 through December 2019, 1167 individuals had panel testing of 12 genes due to the addition of MEN1 and FH. Results: Overall, 27.5% of individuals had a pathogenic or likely pathogenic variant (PV), 9.0% had a variant of uncertain significance, and 63.1% had a negative result. Out of all PVs, most were identified in SDHB (40.4%), followed by SDHD (21.1%), SDHA (10.1%), VHL (7.8%), SDHC (6.7%), RET (3.8%), and MAX (3.6%). PVs in FH, MEN1, NF1, SDHAF2, and TMEM127 collectively accounted for 6.5% of PVs. Clinical predictors of a PV included extra-adrenal location, diagnosis before the age of 45 years, multiple tumors, and positive family history (fhx) of PPGL. Affected individuals with a fhx of PPGL were the most likely to have a PV (70.6% of individuals with PCC + fhx; 85.9% of individuals with PGL + fhx). The positive rate in nearly all clinical subgroups even without predictors of a PV remained over 10%, including individuals with a single tumor (PCC = 16.7%; PGL = 46.7%) and those without a fhx (PCC and negative fhx = 15.8%; PGL and negative fhx = 43.7%). Restricting genetic testing of hereditary PPGL to only SDHB/C/D genes misses a third (31.8%) of individuals with PVs. Among individuals with PVs in syndromic genes, over half (41.5%) did not have any additional syndromic features beyond PPGL reported by the ordering clinician. Conclusion: Our data demonstrate a high diagnostic yield in individuals with and without established risk factors, a low inconclusive result rate, numerous individuals with syndromic PVs presenting with isolated PPGL, and a substantial contribution to diagnostic yield from rare genes when included in testing. These findings support updating practice guidelines to incorporate universal testing of all individuals with PPGL and the use of concurrent MGPT as the ideal platform.


2021 ◽  
Author(s):  
Tansit Saengkaew ◽  
Heena R Patel ◽  
Kausik Banerjee ◽  
Gary Butler ◽  
Mehul Tulsidas Dattani ◽  
...  

Context: Pubertal delay can be the clinical presentation of both idiopathic hypogonadotropic hypogonadism (IHH) and self-limited delayed puberty (SLDP). Distinction between these conditions is a common but important diagnostic challenge in adolescents. Objective: To assess whether gene panel testing can assist with clinical differential diagnosis, to allow accurate and timely management of delayed puberty patients. Design: Retrospective study Methods: Patients presenting with delayed puberty to UK Paediatric services, followed up to final diagnosis, were included. Whole-exome sequencing was analysed using a virtual panel of genes previously reported to cause either IHH or SLDP to identify rare, predicted deleterious variants. Deleterious variants were verified by in silico prediction tools. The correlation between clinical and genotype diagnosis was analysed. Results: Forty-six patients were included, 54% with a final clinical diagnosis of SLDP and 46% with IHH. Red flags signs of IHH were present in only 3 patients. Fifteen predicted deleterious variants in 12 genes were identified in 33% of the cohort, with most inherited in a heterozygous manner. A fair correlation between final clinical diagnosis and genotypic diagnosis was found. Panel testing was able to confirm a diagnosis of IHH in patients with pubertal delay. Genetic analysis identified three patients with IHH that had been previously diagnosed as SLDP. Conclusion:This study supports the use of targeted exome sequencing in the clinical setting to aid the differential diagnosis between IHH and SLDP in adolescents presenting with pubertal delay. Genetic evaluation thus facilitates earlier and more precise diagnosis, allowing clinicians to direct treatment appropriately.


2017 ◽  
Vol 35 (4_suppl) ◽  
pp. 244-244
Author(s):  
Anna K McGill ◽  
Sheila R Solomon ◽  
Megan L Marshall ◽  
Lisa Susswein ◽  
Corrine Fillman ◽  
...  

244 Background: Pancreatic ductal adenocarcinoma (PC) is associated with multiple hereditary cancer syndromes. Genes implicated in hereditary PC include ATM, BRCA1, BRCA2, CDKN2A, EPCAM, MLH1, MSH2, MSH6, PALB2 and PMS2. The advent of multi-gene hereditary cancer panel testing streamlines diagnoses and medical management for clinicians and patients. Our objective was to assess the yield of pathogenic/likely pathogenic variants (PV/LPV) in individuals with PC undergoing panel testing as an initial test at GeneDx. Methods: We retrospectively reviewed panel test results of 605 individuals reporting a personal history of PC. Panel testing evaluated up to 32 genes associated with hereditary cancer. Individuals reporting neuroendocrine pathology or previous BRCA1/BRCA2 testing were excluded. Results: In this cohort, 61 PV/LPV were detected in 57 individuals in the following genes: ATM (17), BRCA2 (14), BRCA1 (5), CDKN2A (5), PALB2 (5), CHEK2 (4), MLH1 (2), MUTYH (2), PMS2 (2), BARD1 (1), FANCC (1), MSH2 (1), RAD51D (1) and TP53 (1), corresponding to a positive yield of 9.4% (57/605). Fifty-one of 61 PV/LPV were detected in genes associated with PC (84%) while 10 PV/LPV (16%) were identified in other genes including BARD1, CHEK2, FANCC, MUTYH, and RAD51D. The diagnostic yield among those reporting a family history of PC (33/294, 11.2%) was not statistically different from those without a reported family history (24/311, 7.7%). However, PV/LPV in ATM were detected more often in individuals reporting a family history of PC compared to those without a family history (4.1% vs. 1.6%, p=0.018). Conclusions: In total, 9.4% of patients with PC tested positive for PV/LPV in 14 different genes by panel testing. Although the majority of PV/LPV were identified in known PC genes, 16% of positive findings occurred in genes not typically associated with PC. ATM was most commonly implicated and more frequently reported in patients reporting family histories of PC. Assessing whether these genes are indeed causally related to PC and/or are possibly associated with other cancer types requires further investigation. Based on our results we conclude multi-gene panel testing may be considered as a first option for patients with PC regardless of their family history.


Cancers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 1007 ◽  
Author(s):  
Lorenza Pastorino ◽  
Virginia Andreotti ◽  
Bruna Dalmasso ◽  
Irene Vanni ◽  
Giulia Ciccarese ◽  
...  

The contribution of recently established or candidate susceptibility genes to melanoma missing heritability has yet to be determined. Multigene panel testing could increase diagnostic yield and better define the role of candidate genes. We characterized 273 CDKN2A/ARF and CDK4-negative probands through a custom-designed targeted gene panel that included CDKN2A/ARF, CDK4, ACD, BAP1, MITF, POT1, TERF2IP, ATM, and PALB2. Co-segregation, loss of heterozygosity (LOH)/protein expression analysis, and splicing characterization were performed to improve variant classification. We identified 16 (5.9%) pathogenic and likely pathogenic variants in established high/medium penetrance cutaneous melanoma susceptibility genes (BAP1, POT1, ACD, MITF, and TERF2IP), including two novel variants in BAP1 and 4 in POT1. We also found four deleterious and five likely deleterious variants in ATM (3.3%). Thus, including potentially deleterious variants in ATM increased the diagnostic yield to about 9%. Inclusion of rare variants of uncertain significance would increase the overall detection yield to 14%. At least 10% of melanoma missing heritability may be explained through panel testing in our population. To our knowledge, this is the highest frequency of putative ATM deleterious variants reported in melanoma families, suggesting a possible role in melanoma susceptibility, which needs further investigation.


2019 ◽  
pp. 1-12 ◽  
Author(s):  
Gregory E. Idos ◽  
Allison W. Kurian ◽  
Charité Ricker ◽  
Duveen Sturgeon ◽  
Julie O. Culver ◽  
...  

Purpose Multiplex gene panel testing (MGPT) allows for the simultaneous analysis of germline cancer susceptibility genes. This study describes the diagnostic yield and patient experiences of MGPT in diverse populations. Patients and Methods This multicenter, prospective cohort study enrolled participants from three cancer genetics clinics—University of Southern California Norris Comprehensive Cancer Center, Los Angeles County and University of Southern California Medical Center, and Stanford Cancer Institute—who met testing guidelines or had a 2.5% or greater probability of a pathogenic variant (N = 2,000). All patients underwent 25- or 28-gene MGPT and results were compared with differential genetic diagnoses generated by pretest expert clinical assessment. Post-test surveys on distress, uncertainty, and positive experiences were administered at 3 months (69% response rate) and 1 year (57% response rate). Results Of 2,000 participants, 81% were female, 41% were Hispanic, 26% were Spanish speaking only, and 30% completed high school or less education. A total of 242 participants (12%) carried one or more pathogenic variant (positive), 689 (34%) carried one or more variant of uncertain significance (VUS), and 1,069 (53%) carried no pathogenic variants or VUS (negative). More than one third of pathogenic variants (34%) were not included in the differential diagnosis. After testing, few patients (4%) had prophylactic surgery, most (92%) never regretted testing, and most (80%) wanted to know all results, even those of uncertain significance. Positive patients were twice as likely as negative/VUS patients (83% v 41%; P < .001) to encourage their relatives to be tested. Conclusion In a racially/ethnically and socioeconomically diverse cohort, MGPT increased diagnostic yield. More than one third of identified pathogenic variants were not clinically anticipated. Patient regret and prophylactic surgery use were low, and patients appropriately encouraged relatives to be tested for clinically relevant results.


2021 ◽  
Vol 42 (Supplement_1) ◽  
Author(s):  
J M Murphy ◽  
C W Kirk ◽  
J Galvin ◽  
D Ward ◽  
T Prendiville ◽  
...  

Abstract Background Inherited cardiomyopathies (hypertrophic, dilated and arrhythmogenic) and cardiac ion channelopathies (long QT, Brugada and CPVT) predispose to sudden cardiac death/sudden arrhythmic death syndrome. Given their genetically heterogenous nature, multi-gene DNA sequencing panels are useful to aid genetic diagnosis. Purpose Investigate the diagnostic yield from cardiac gene panel testing undertaken in patients (including molecular autopsy in deceased patients) referred to four clinical services from 2002 to 2020. Methods Data was collected by interrogation of departmental databases, family charts, and review of molecular genetic diagnostic reports. Results We evaluated molecular genetic diagnostic results from 835 individuals (461 males, 374 females) from 824 families, including 58 deceased patients who underwent molecular autopsy. The median age of the cohort was 44 years (range 0.1–86 years). Testing for hypertrophic cardiomyopathy (HCM) and long QT syndrome (LQT) genes represented 36% and 32% of the cohort, respectively, with the remaining 32% accounting for other cardiomyopathies, arrhythmia syndromes or metabolic/syndromic diseases. The overall variant detection rate was 50% across all panel types. Three hundred and fifty patients (42%) carried a single variant, 68 patients (8%) carried multiple variants (up to a maximum of four), including two individuals who carried two actionable (pathogenic/likely pathogenic) variants each and 30 individuals (5%) with one actionable variant plus a variant of uncertain significance (VUS). The overall diagnostic yield of at least one actionable variant was 28%. At least one VUS was detected in 27% of the cohort. Molecular autopsy yielded an actionable variant in 10% of patients, while 30% of the subcohort carried at least one VUS (up to maximum of two). We found a positive association between female sex and the likelihood of detecting an actionable variant. By decade of age, detection of actionable variants ranged from 19% (60–69 years) to 41% (0–9 years). By panel type, actionable variants ranged from 14% (Brugada) to 35% (cardiomyopathy). The burden of VUS ranged from 22% (LQT) to 46% (dilated cardiomyopathy). Altogether 234 actionable variants were detected in 26 genes, including seven metabolic or syndromic disease genes. From those with non-metabolic/syndromic forms of disease, 84% of actionable variants were detected in well established ICC genes. Analysis of gene-disease associations for VUS detected from HCM and LQT panels revealed that 10–25% were detected in genes now deemed to have only moderate or limited evidence of disease causation. Conclusion Most actionable variants in this cohort were detected in well-established ICC genes, suggesting that large gene panels offer little extra sensitivity compared to historic smaller gene panels. Despite recent gene curation efforts, the high burden of VUS remains a considerable challenge in ICC management. FUNDunding Acknowledgement Type of funding sources: Foundation. Main funding source(s): National Children's Research Centre


Sign in / Sign up

Export Citation Format

Share Document