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Answer ALS is a biological and clinical resource of patient-derived, induced pluripotent stem (iPS) cell lines, multi-omic data derived from iPS neurons and longitudinal clinical and smartphone data from over 1,000 patients with ALS. This resource provides population-level biological and clinical data that may be employed to identify clinical–molecular–biochemical subtypes of amyotrophic lateral sclerosis (ALS). A unique smartphone-based system was employed to collect deep clinical data, including fine motor activity, speech, breathing and linguistics/cognition. The iPS spinal neurons were blood derived from each patient and these cells underwent multi-omic analytics including whole-genome sequencing, RNA transcriptomics, ATAC-sequencing and proteomics. The intent of these data is for the generation of integrated clinical and biological signatures using bioinformatics, statistics and computational biology to establish patterns that may lead to a better understanding of the underlying mechanisms of disease, including subgroup identification. A web portal for open-source sharing of all data was developed for widespread community-based data analytics.

ObjectiveIn 2021, the Clinical Genome Resource (ClinGen) amyotrophic lateral sclerosis (ALS) spectrum disorders Gene Curation Expert Panel (GCEP) was established to evaluate the strength of evidence for genes previously reported to be associated with ALS. Through this endeavor, we will provide standardized guidance to laboratories on which genes should be included in clinical genetic testing panels for ALS. In this manuscript, we aimed to assess the heterogeneity in the current global landscape of clinical genetic testing for ALS.MethodsWe reviewed the National Institutes of Health (NIH) Genetic Testing Registry (GTR) and members of the ALS GCEP to source frequently used testing panels and compare the genes included on the tests.Results14 clinical panels specific to ALS from 14 laboratories covered 4 to 54 genes. All panels report on ANG, SOD1, TARDBP, and VAPB; 50% included or offered the option of including C9orf72 hexanucleotide repeat expansion (HRE) analysis. Of the 91 genes included in at least one of the panels, 40 (44.0%) were included on only a single panel. We could not find a direct link to ALS in the literature for 14 (15.4%) included genes.ConclusionsThe variability across the surveyed clinical genetic panels is concerning due to the possibility of reduced diagnostic yields in clinical practice and risk of a missed diagnoses for patients. Our results highlight the necessity for consensus regarding the appropriateness of gene inclusions in clinical genetic ALS tests to improve its application for patients living with ALS and their families.

Preliminary evidence suggests that commonly used genetic tests may be less likely to identify a genetic etiology for ALS-FTD in patients of underrepresented race, ethnicity, and ancestry (REA), as compared to European REA. Patients of underrepresented REA may therefore be less likely to receive accurate and specific genetic counseling information and less likely to have access to gene-targeted therapies currently in clinical trials. We compiled outcome data from 1911 ALS-FTD patients tested at a commercial laboratory over a seven-year period for C9orf72 hexanucleotide repeat expansion (HRE) alone or C9orf72 and multigene sequencing panel testing. We compared the incidence of pathogenic (P), likely pathogenic (LP), and uncertain variants in C9orf72 and other ALS-FTD genes, as well as age at testing, in patients of different REA. The diagnostic rate in patients of European REA (377/1595, 23.64%) was significantly higher than in patients of underrepresented REA (44/316, 13.92%) (p < 0.001). Patients of European REA were more likely to have the C9orf72 HRE (21.3%) than patients of underrepresented REA (10.4%) (p < 0.001). The overall distribution of positive test outcomes in all tested genes was significantly different between the two groups, with relatively more P and LP variants in genes other than C9orf72 identified in patients of underrepresented REA. The incidence of uncertain test outcomes was not significantly different between patients of European and underrepresented REA. Patients with positive test outcomes were more likely to be younger than those with negative or uncertain outcomes. Although C9orf72 HRE assay has been advocated as the first, and in some cases, only genetic test offered to patients with ALS-FTD in the clinical setting, this practice may result in the reduced ascertainment of genetic ALS-FTD in patients of diverse REA.

Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are devastating neurodegenerative disorders that share clinical, pathologic, and genetic features. Persons and families affected by these conditions frequently question why they developed the disease, the expected disease course, treatment options, and the likelihood that family members will be affected. Genetic testing has the potential to answers these important questions. Despite the progress in gene discovery, the offer of genetic testing is not yet "standard of care" in ALS and FTD clinics. The authors review the current genetic landscape and present recommendations for the laboratory genetic evaluation of persons with these conditions.

Studies have shown that patients with hypertrophic cardiomyopathy (HCM) may misinterpret the meaning of uninformative genetic testing results to mean that a genetic etiology and family members' risk is ruled out. We hypothesized that poor comprehension of the laboratory genetic test report may contribute to this misunderstanding. We conducted a qualitative study to examine patient understanding of uninformative laboratory results and reports and elicit suggestions for an improved report. Fifteen participants with HCM were interviewed after undergoing genetic testing and receiving their report. While all patients read the report, most participants reported only partially reading it. Most reported not understanding the report at all or only partially understanding it because a provider explained it to them. Some participants said that the report was helpful for understanding their result, but there was evidence of misunderstanding; most participants stated that specific aspects of the report were unhelpful. While most of our participants communicated risk with relatives, none said that the report helped with the communication. Most participants did not recall or find the accompanying physician-directed result letter useful for their understanding or familial communication. Many participants expressed need for a supplemental report that illustrates a personalized clinical 'action plan' that could summarize clinical and familial implications of the result for the patient and their family. We conclude that laboratory reports and physician-directed result letters did not help participants understand their results or their familial implications. Our results suggest opportunities for research to explore the utility of a patient-directed result supplement to improve patient comprehension of genetic test results and outline clinical recommendations via a patient action plan.

Background Skeletal development and maintenance are complex processes known to be coordinated by multiple genetic and epigenetic signaling pathways. However, the role of long non-coding RNAs (lncRNAs), a class of crucial epigenetic regulatory molecules, has been under explored in skeletal biology. Results Here we report a young patient with short stature, hypothalamic dysfunction and mild macrocephaly, who carries a maternally inherited 690 kb deletion at Chr.1q24.2 encompassing a noncoding RNA gene, DNM3OS, embedded on the opposite strand in an intron of the DYNAMIN 3 (DNM3) gene. We show that lncRNA DNM3OS sustains the proliferation of chondrocytes independent of two co-cistronic microRNAs miR-199a and miR-214. We further show that nerve growth factor (NGF), a known factor of chondrocyte growth, is a key target of DNM3OS-mediated control of chondrocyte proliferation. Conclusions This work demonstrates that DNM3OS is essential for preventing premature differentiation of chondrocytes required for bone growth through endochondral ossification.

Andersen-Tawil syndrome is a rare, autosomal dominant, multisystem disorder for which the majority of cases are caused by pathogenic variants in the KCNJ2 gene. The syndrome is characterized by the clinical triad of episodic paralysis, cardiac conduction abnormalities, and dysmorphic facial and skeletal features. Treatment of Andersen-Tawil syndrome is primarily focused on management of cardiac arrhythmias and preventive management of paralytic attacks. Dichlorphenamide is approved by the US Food and Drug Administration for use in primary periodic paralysis based on several randomized, controlled trials but has not been studied in patients with Andersen-Tawil syndrome. Here, we report a case of the syndrome caused by a de novo pathogenic variant in the KCNJ2 gene (c.95_98del). The paralytic attack rate for this patient was better controlled with dichlorphenamide compared with acetazolamide, further supporting the use of dichlorphenamide in patients with Andersen-Tawil syndrome.

Background: Skeletal development and maintenance are complex processes known to be coordinated by multiple genetic and epigenetic signaling pathways. However, the role of long non-coding RNAs (lncRNAs), a class of crucial epigenetic regulatory molecules, has been under explored in skeletal biology. Results: Here we report a young patient with short stature, hypothalamic dysfunction and mild macrocephaly, who carries a maternally inherited 690kb deletion at Chr.1q24.2 encompassing a noncoding RNA gene, DNM3OS, embedded on the opposite strand in an intron of the DYNAMIN 3 (DNM3)gene. We show that lncRNA DNM3OS sustains the proliferation of chondrocytes independent of two co-cistronic microRNAs miR-199a and miR-214. We further show that nerve growth factor (NGF), a known factor of chondrocyte growth, is a key target of DNM3OS-mediated control of chondrocyte proliferation.Conclusion: This work demonstrates that DNM3OS is essential for preventing premature differentiation of chondrocytes required for bone growth through endochondral ossification.

Genome-wide association studies (GWAS) and rare variant association studies (RVAS) are applied across many areas of complex disease to analyze variation in whole genomes of thousands of unrelated patients. These approaches are able to identify variants and/or biological pathways which are associated with disease status and, in contrast to traditional linkage studies or candidate gene approaches, do so without requiring multigenerational affected families, prior hypotheses, or known genes of interest. However, the novel associations identified by these methods typically have lower effect sizes than those found in classical family studies. In the motor neuron disease amyotrophic lateral sclerosis (ALS), GWAS, and RVAS have been used to identify multiple disease-associated genes but have not yet resulted in novel therapeutic interventions. There is significant urgency within the ALS community to identify additional genetic markers of disease to uncover novel biological mechanisms, stratify genetic subgroups of disease, and drive drug development. Given the widespread and increasing application of genetic association studies of complex disease, it is important to recognize the strengths and limitations of these approaches. Here, we review ALS gene discovery via GWAS and RVAS.

Background Amyotrophic lateral sclerosis (ALS) is increasingly recognized as a genetic disease. There is no consensus, however, as to the role of genetic testing in the care of the ALS patient. Methods We conducted a survey to study patient access, attitudes, and experience with ALS genetic testing among patients enrolled in a US ALS registry. Results Among 449 survey respondents, 156 (34.7%) were offered testing and 105 of 156 (67.3%) completed testing. The majority of respondents with familial ALS (fALS) (31/45, 68.9%) were offered testing, while a minority of respondents with sporadic ALS (sALS) (111/404, 27.5%) were offered testing (p = .00001). Comparison of mean test experience scores between groups revealed that respondents with fALS were no more likely to report a favorable experience with genetic testing than those with sALS (p = .51). Respondents who saw a genetic counselor did not have significantly different test experience scores, compared to those who did not (p = .14). In addition, no differences in test experience scores were observed between those who received positive or negative genetic test results (p = .98). Conclusion These data indicate that patients with ALS found value in clinical genetic testing.

Introduction: Inherited myotonic disorders are genetically heterogeneous and associated with overlapping clinical features of muscle stiffness, weakness, and pain. Data on genotype-phenotype correlations are limited. In this study, clinical features and treatment patterns in genetically characterized myotonic disorders were compared. Methods: A retrospective chart review was completed in patients with genetic variants in CLCN1, SCN4A, DMPK, and CNBP to document clinical signs and symptoms, clinical testing, and antimyotonia medication use. Results: A total of 142 patients (27 CLCN1, 15 SCN4A, 89 DMPK, and 11 CNBP) were reviewed. The frequency of reported symptoms (stiffness, weakness, and pain) and electromyographic spontaneous activity were remarkably similar across genotypes. Most patients were not treated with antimyotonia agents, but those with non-dystrophic disorders were more likely to be on a treatment. Discussion: Among the features reviewed, we did not identify clinical or electrophysiological differences to distinguish CLCN1- and SCN4A-related myotonia. Weakness and pain were more prevalent in non-dystrophic disorders than previously identified. In addition, our results suggest that medical treatments in myotonic disorders may be under-utilized.

Background: A genetic basis is found in ∼70% of familial and ∼15% of sporadic ALS, in research cohorts. Clinical trials of gene-targeted therapies are underway, heralding a new era of personalized medicine in ALS treatment. However, ALS management guidelines do not include recommendations for the offer of genetic testing. Many persons with ALS who desire genetic testing are not currently offered it, and the yield of genetic testing in clinic-based ALS populations is unknown. The ALS GAP program, sponsored by the Northeast ALS (NEALS) Consortium, provides free genetic testing for patients with ALS who have a family history of ALS or dementia. We report genetic testing outcomes in the first 142 patients tested in the program.Objectives: 1) To create a pilot ALS genetic testing program for NEALS clinics, 2) To study the rate of ALS gene identification in a US clinic-based populationMethods: Persons with ALS and a family history of ALS (fALS) or dementia (dALS) who receive care at a US NEALS clinic are eligible for testing. Patients classified as fALS (having a positive family history of ALS in a 1st, 2nd, or 3rd degree relative) are eligible for C9orf72 testing, with the option to reflex to a 5 gene (SOD1, FUS, TARDBP, TBK1, VCP) panel. Patients classified as dALS (having a positive family history of dementia of any type in a 1st or 2nd degree relative) are eligible for C9orf72 testing only.Results: Currently, 29.5% (34/115) of US NEALS clinics have participated in the program. Of 142 patients who have completed testing to date, 78 (54.9%) were classified as fALS and 64 (45.1%) as dALS. Among fALS cases, 42/78 (53.9%) tested positive, including 32/78 (41%) with a C9orf72 repeat expansion, and 10/78 (12.8%) with other pathogenic or likely pathogenic variants in SOD, FUS, TARDP or VCP. Variants of uncertain significance (VUS) in FUS were identified in 2/78 (2.6%). Among dALS cases, 12/60 (20%) tested positive for C9orf72.Discussion and conclusions: Participation in ALS-GAP indicates significant clinician and patient interest in ALS genetic testing. This program addresses several current barriers to testing access, including cost, identifying appropriate candidates for testing, and appropriate test selection. Although 38% of patients who participated in the program have thus far received a genetic diagnosis, our testing outcome data suggests that the gene identification rate in fALS cases may be lower in clinic-based patients than in research cohorts, particularly for genes other than C9orf72. This program may serve as a model for the practice of ALS genetic testing in the clinic setting. Consistent, equitable testing policies, as well as an accurate understanding of the genetic profile of clinic-based ALS populations, are needed as gene-targeted therapies reach patient care.

Recent advances in ALS gene discovery have both empowered and challenged clinicians providing evaluation and care for persons with ALS, many of whom seek an answer as to the cause of their condition. In order to study clinician practices and attitudes towards genetic testing, we surveyed members of the Northeast ALS Consortium, an international group of specialist ALS clinicians; responses were received from 80 of 255 (response rate = 31.4%). While 92.3% indicated they offered genetic testing to patients with familial ALS, 57.0% offered testing to patients with ALS and a family history of dementia, and 36.9% offered testing to patients with sporadic ALS, revealing a lack of consensus with respect to the approach to the typical ALS patient encountered in clinical practice. In addition, comparison of clinician and patient attitudes towards genetic testing revealed that clinicians valued the scientific potential of testing, but were less likely to say they would have testing themselves, or to see the value in testing for family members. People with ALS were more likely to see value of testing for themselves and for family members, and less likely to strongly value the scientific potential of testing.

ObjectiveTo report the frequency of amyotrophic lateral sclerosis (ALS) genetic variants in a nationwide cohort of clinic-based patients with ALS with a family history of ALS (fALS), dementia (dALS), or both ALS and dementia (fALS/dALS).MethodsA multicenter, prospective cohort of 573 patients with fALS, dALS, or fALS/dALS, underwent genetic testing in the ALS Genetic Access Program (ALS GAP), a clinical program for clinics of the Northeast ALS Consortium. Patients with dALS underwent C9orf72 hexanucleotide repeat expansion (HRE) testing; those with fALS or fALS/dALS underwent C9orf72 HRE testing, followed by sequencing of SOD1, FUS, TARDBP, TBK1, and VCP.ResultsA pathogenic (P) or likely pathogenic (LP) variant was identified in 171/573 (30%) of program participants. About half of patients with fALS or fALS/dALS (138/301, 45.8%) had either a C9orf72 HRE or a P or LP variant identified in SOD1, FUS, TARDBP, TBK1, or VCP. The use of a targeted, 5-gene sequencing panel resulted in far fewer uncertain test outcomes in familial cases compared with larger panels used in other in clinic-based cohorts. Among dALS cases 11.8% (32/270) were found to have the C9orf72 HRE. Patients of non-Caucasian geoancestry were less likely to test positive for the C9orf72 HRE, but were more likely to test positive on panel testing, compared with those of Caucasian ancestry.ConclusionsThe ALS GAP program provided a genetic diagnosis to ∼1 in 3 participants and may serve as a model for clinical genetic testing in ALS.

Patients with amyotrophic lateral sclerosis (ALS) often have questions about why they developed the disease and the likelihood that family members will also be affected. In recent years, providing answers to these questions has become more complex with the identification of multiple novel genes, the newly recognized etiologic link between ALS and frontotemporal dementia (FTD), and the increased availability of commercial genetic testing. A genetic diagnosis is particularly important to establish in the era of emerging gene-based therapies, such as SOD1 antisense oligonucleotide trials. In the span of a few years, ALS genetic testing options have progressed from testing of a single gene to multigene next-generation sequencing panels and whole-exome sequencing. This article provides suggestions for genetic counseling and genetic testing for ALS in this new environment. Genet Med 19 3, 267–274.

Introduction: Distal hereditary motor neuropathy (dHMN) causes distal-predominant weakness without prominent sensory loss. Myosin heavy chain disorders most commonly result in distal myopathy and cardiomyopathy with or without hearing loss, but a complex phenotype with dHMN, myopathy, hoarseness, and hearing loss was reported in a Korean family with a c.2822G>T mutation in MYH14. Objective: To report phenotypic features in a North American family with the c.2822G>T in MYH14. Methods: Clinical and molecular characterization was performed in a large, 6-generation, Caucasian family with MYH14 dHMN. Results: A total of 11 affected and 7 unaffected individuals were evaluated and showed varying age of onset and severity of weakness. Genotypic concordance was confirmed with molecular analysis. Electrophysiological studies demonstrated distal motor axonal degeneration without myopathy in all affected subjects tested. Conclusions: Mutation of MYH14 can result in a range of neuromuscular phenotypes that includes a dHMN and hearing loss phenotype with variable age of onset. This article is protected by copyright. All rights reserved.

The 2011 discovery of the pathogenic hexanucleotide repeat expansion (HRE) in C9orf72, the leading genetic cause of both amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), marked a breakthrough in the effort to unravel the etiology of these conditions. Ten years later, clinicians are still working to integrate the implications of this discovery into the care of individuals with ALS and/or FTD. Consensus management guidelines for ALS do not comprehensively address the issue of genetic testing, and questions remain about whom to test, what counseling should be provided before and after testing, laboratory methods, and test interpretation. These challenges have contributed to inconsistent clinical practices and present barriers to patients wishing to access testing. This review summarizes the clinical impact of the discovery of the C9orf72 HRE, outlines ongoing challenges, and provides recommendations for C9orf72 testing, counseling, and research.

ObjectiveTo determine the incidence of amyotrophic lateral sclerosis (ALS) genetic variants in a clinic-based population.MethodsA prospective cohort of patients with definite or probable ALS was offered genetic testing using a testing algorithm based on family history and age at onset.ResultsThe incidence of pathogenic (P) or likely pathogenic (LP) variants was 56.0% in familial ALS (fALS); 11.8% in patients with ALS with a family history of dementia, and 6.8% in sporadic ALS (p < 0.001). C9orf72 expansions accounted for the majority (79%) of P or LP variants in fALS cases. Variants of uncertain significance were identified in 20.0% of fALS cases overall and in 35.7% of C9orf72-negative cases. P or LP variants were detected in 18.5% of early-onset cases (onset age ConclusionsOur data suggest that the incidence of P and LP variants in genes other than C9orf72 is lower than expected in Midwestern fALS cases compared with research cohorts and highlights the challenge of variant interpretation in ALS. An accurate understanding of the incidence of pathogenic variants in clinic-based ALS populations is necessary to prioritize targets for therapeutic intervention and inform clinical trial design.

Genetic counseling summary letters are intended to reinforce information received during genetic counseling, but little information is available on patient/family responses to these letters. We conducted a case-control study to assess the effectiveness of two different letter formats. Parents of children receiving a new diagnosis were enrolled. The control group (n = 85) received a genetic counseling summary letter in a narrative format, 4-5 pages in length. After the control enrollment period, genetic counselors were trained by a professional medical writer to develop a concise letter format. The case group (n = 64) received a concise letter, approximately 1.5 pages in length, utilizing simple sentences, lay terms, and lists/bullet points. Parents completed a survey 4 weeks after the visit to rate the letter's format, usefulness, and their emotional reaction. Results show that parents in the case group rated the letter more highly (p = 0.023), particularly in the emotional response dimension (rating changes in anxiety, depression, fear, ability to cope, and confidence in response to the letter). Parents in the case group also rated the genetic counseling session more highly (p = 0.039). In the control group, parents without a college degree were more likely to rate the letter as too long and the level of medical detail as too high. In the case group, no significant differences were seen between parents with or without a college degree. These data suggest that a short genetic counseling summary letter is rated higher by parents, and is particularly associated with a more positive emotional reaction. A short letter format highlighting the basic facts related to the genetic condition may be more useful to parents of diverse educational backgrounds, and may support a positive emotional adaptation at the time of a new diagnosis. Genetic counselors may benefit from specific instruction in medical and educational writing.

Distal hereditary motor neuropathy (dHMN) causes distal-predominant weakness without prominent sensory loss. Myosin heavy chain disorders most commonly result in distal myopathy and cardiomyopathy with or without hearing loss, but a complex phenotype with dHMN, myopathy, hoarseness, and hearing loss was reported in a Korean family with a c.2822GT mutation in MYH14. In this study we report phenotypic features in a North American family with the c.2822GT in MYH14.Clinical and molecular characterization was performed in a large, 6-generation, Caucasian family with MYH14 dHMN.A total of 11 affected and 7 unaffected individuals were evaluated and showed varying age of onset and severity of weakness. Genotypic concordance was confirmed with molecular analysis. Electrophysiological studies demonstrated distal motor axonal degeneration without myopathy in all affected subjects tested.Mutation of MYH14 can result in a range of neuromuscular phenotypes that includes a dHMN and hearing loss phenotype with variable age of onset. Muscle Nerve 56: 341-345, 2017.

Although genetic testing for amyotrophic lateral sclerosis (ALS) is widely available, it is unknown what proportion of patients with ALS have access to genetic counseling and testing, and patient attitudes towards ALS genetic testing have not been studied. We conducted a national survey of ALS patients enrolled in the Agency for Toxic Substances and Disease Registry, which consisted of multiple choice questions and two 12 item Likert scale series assessing respondents' experience with and attitude toward genetic testing. The survey had an 8 % response rate, with 449 completed responses. Genetic testing was offered to 33.4 % and completed by 67.1 % of those offered. A minority of respondents (12.5 %) saw a genetic counselor, and were much more likely to be offered genetic testing (p = 0.0001). Respondents with a family history of ALS (8.4 %) were more likely to be offered testing (p = 0.0001) and complete testing (p = 0.05). Respondents with a family history of ALS were more likely to report a favorable attitude towards genetic testing (p = 0.0003), as were respondents who saw a genetic counselor (p = 0.02). The majority of respondents (82.7 %) felt that genetic testing should be offered to all patients with ALS. Our results indicate that ALS patients may have limited access to genetic testing, but perceive benefit from this service. Development of practice guidelines for genetic testing in ALS, to include the routine offer of genetic counseling, may result in broader and more consistent access to these services.

Ten years ago, commercial ALS genetic testing was limited to SOD1 sequencing. Commercial laboratories now offer a variety of multigene ALS panels, assays for the C9orf72 hexanucleotide expansion, and whole exome sequencing. The utility of genetic testing as part of ALS clinical management is valued by people with ALS1 and ALS clinicians.2 However, US care guidelines do not address the offer of genetic testing, and European guidelines specify that ALS genetic testing should be offered only to patients with familial ALS or the SOD1 D90A phenotype.3 To understand the current state of ALS genetic testing, we surveyed certified commercial laboratories to gather data on test methods, outcomes, and reporting.

Patients with trisomies or duplications of distal 15q have rarely been reported in the literature. Previous authors [Zollino et al., 1999: Am J Med Genet 87:391-394] have described a distal 15q trisomy syndrome, including the unusual features of prenatal overgrowth, tall stature, macrocephaly, and craniosynostosis. We report three new patients with a duplication of 15q24-q26.3; features common to the two surviving patients include ptosis, small size, and developmental delay. None of these patients had craniosynostosis or overgrowth. We propose that the previously described distal 15q trisomy syndrome [Zollino et al., 1999: Am J Med Genet 87:391-394] may result from specific disruption of a gene linked to 15q25, rather than partial trisomy for the region.

Germline mutations in the PTEN/MMAC1/TEP1 tumor suppressor gene cause Cowden syndrome (CS), a hereditary hamartoma-tumor syndrome with an increased risk of breast, thyroid, and endometrial cancers, and seemingly unrelated developmental disorders, such as Bannayan-Riley-Ruvalcaba (BRR) syndrome,Proteus, and Proteus-like syndromes. Data to date suggest that irrespective of the clinical presentation, the identification of a PTENmutation should trigger medical management which includes cancer surveillance. Clinic-based molecular diagnostic testing for germline PTEN mutations has been available for at least 2 years. This study reports on the finding of a previously unobserved heterozygous alteration (IVS7–15→53del39) found in an African American individual who had features of CS. Further investigation revealed that 12 of 42 (28.6%) African American controls, but not individuals of Caucasian or Japanese origin, also carried this heterozygous 39-bp deletion in PTEN. Due to its location immediately upstream of the splicing site of exon 8, this polymorphism could be mistaken for a deleterious mutation in the PTEN.

We report a 3-year-old girl with trisomy 2p24.3-pter who presented with marked psychomotor delay and dysmorphic features. This patient represents the only known case of trisomy 2p24.3-2pter that does not involve an associated functional monosomy. In contrast to recent reports highlighting the fatal or serious complications in patients described as having partial trisomy 2p, this patient does not have significant birth defects or life threatening medical problems. Notably, this patient does not have a neural tube defect (NTD), which has been attributed to a putative locus at 2p24 in other patients with a partial trisomy 2p.

A mailed survey of female prenatal genetic counselors, obstetric nurses, and high school biology teachers was conducted to determine if these groups hold different attitudes toward genetic risk and to investigate the extent to which any differences result from the effect of different professional experiences. In this study, the participants were 166 genetic counselors, 116 obstetric nurses, and 78 biology teachers (n=360). Survey participants completed a written questionnaire designed to assess their numeric estimate of the empiric risk for birth defects/genetic problems, their subjective perception of this risk, and their personal use of prenatal diagnosis. Genetic counselors were found to be less likely than the other groups to consider the frequency of birth defects/genetic problems as rare and were 10 times more likely than nurses and 8 times more likely than teachers to have had prenatal diagnosis. Furthermore, more than half of the prenatal diagnosis procedures had by genetic counselors were not medically indicated. These results suggest that genetic counselors have an increased perception of genetic risks relative to nurses or teachers. Possible explanations for this funding are discussed, and the potential role of discordant risk perception in creating biases in genetic counseling process is explored.

We identified two families with an autosomal-recessive disorder manifested by severe enamel hypoplasia, delayed and failed tooth eruption, misshapen teeth, intrapulpal calcifications, and localized gingival hyperplasia. Genetic analyses identified novel FAM20A mutations associated with the disease phenotype in both families. The proband of Family 1 had an altered splice junction in Intron 1 (g.502011G>C; c.405-1G>C) and a missense mutation in Exon 8 (g.65094G>A; c.1207G>A; p.D403N). The missense mutation is notable because D403 is strictly conserved among FAM20A homologues, and the corresponding defect in FAM20C caused osteosclerotic bone dysplasia and a loss of kinase activity. The proband at age 12 yrs tested negative for nephrocalcinosis. The proband and her affected father in Family 2 were homozygous for a single nucleotide deletion that altered a splice junction in Intron 10 (g.66622del; c.1361+4del). Minigene analyses demonstrated that this alteration precluded normal splicing. Immunohistochemistry (IHC) of mouse maxillary first molars localized FAM20A in secretory-stage ameloblasts, in odontoblasts, and in the eruption pathway. IHC of kidneys localized FAM20A in the renal tubules. We conclude that FAM20A is likely a secretory pathway kinase and that loss-of-function mutations cause pathology where its phosphorylations are necessary for normal development or homeostasis.

In Minnesota and other states, all newborns are screened for cystic fibrosis (CF). CF is a common genetic condition that affects the sinopulmonary, hepatobiliary and male urogenital systems. Cystic fibrosis is caused by mutations in both copies of the CF transmembrane conductance regulator (CFTR) gene. In Minnesota, infants who have elevated immunoreactive trypsinogen (IRT) at birth are tested for a panel of 39 mutations. Newborn screening detects most infants with two CFTR mutations as well as some who are CF carriers. This method of newborn screening leads to the identification of some individuals with milder forms of CFTR dysfunction whose clinical diagnosis is unclear. The Cystic Fibrosis Foundation has designated diagnostic and management guidelines for CFTR-related metabolic syndrome (CRMS) for infants who have evidence of CFTR dysfunction but who do not meet the diagnostic criteria for CF. This article discusses the clinical impact of CRMS in Minnesota.

Interpretation of the pathogenicity of sequence alterations in disease-associated genes is challenging. This is especially true for novel alterations that lack obvious functional consequences. We report here on a patient with Treacher Collins syndrome (TCS) found to carry a previously reported mutation, c.122C > T, which predicts p.A41V, and a novel synonymous mutation, c.3612A > C. Pedigree analysis showed that the c.122C > T mutation segregated with normal phenotypes in multiple family members while the c.3612A > C was de novo in the patient. Analysis of TCOF1 RNA in lymphocytes showed a transcript missing exon 22. These results show that TCS in the patient is due to haploinsufficiency of TCOF1 caused by the synonymous de novo c.3612A > C mutation. This study highlights the importance of clinical and pedigree evaluation in the interpretation of known and novel sequence alterations.

Charcot-Marie-Tooth (CMT) disease is the most common hereditary polyneuropathy and is classically associated with an insidious onset of distal predominant motor and sensory loss, muscle wasting, and pes cavus. Other forms of hereditary neuropathy, including sensory predominant or motor predominant forms, are sometimes included in the general classification of CMT, but for the purpose of this review, we will focus primarily on the forms associated with both sensory and motor deficits. CMT has a great deal of genetic heterogeneity, leading to diagnostic considerations that are still rapidly evolving for this disorder. Clinical features, inheritance pattern, gene mutation frequencies, and electrodiagnostic features all are helpful in formulating targeted testing algorithms in practical clinical settings, but these still have shortcomings. Next-generation sequencing (NGS), combined with multigene testing panels, is increasing the sensitivity and efficiency of genetic testing and is quickly overtaking targeted testing strategies. Currently, multigene panel testing and NGS can be considered first-line in many circumstances, although obtaining initial targeted testing for the PMP22 duplication in CMT patients with demyelinating conduction velocities is still a reasonable strategy. As technology improves and cost continues to fall, targeted testing will be completely replaced by multigene NGS panels that can detect the full spectrum of CMT mutations. Nevertheless, clinical acumen is still necessary given the variants of uncertain significance encountered with NGS. Despite the current limitations, the genetic diagnosis of CMT is critical for accurate prognostication, genetic counseling, and in the future, specific targeted therapies. Although whole exome and whole genome sequencing strategies have the power to further elucidate the genetics of CMT, continued technological advances are needed.

Editor—The immunodeficiency, centromeric region instability, and facial anomalies syndrome (ICF) usually involves mutations affecting the catalytic domain in DNMT3B, one of the three human genes known to encode DNA methyltransferases.1-3 ICF always results in defective immunity, a high frequency of chromosomal abnormalities in the vicinity of the centromere (pericentromeric region) of chromosome 1 and/or chromosome 16 in mitogen stimulated lymphocytes, and hypomethylation of a small portion of the genome.4-6 ICF symptoms are manifested often from infancy and this syndrome can cause early childhood death from infections. The DNA sequences targeted for undermethylation in ICF include the heterochromatin adjacent to the centromeres of chromosomes 1 and 16 (1qh and 16qh), where a high incidence of chromatin decondensation, chromosome and chromatid breaks, and rearrangements to form multiradial chromosomes are characteristically seen in mitogen stimulated ICF blood cultures and in ICF lymphoblastoid cell lines.6-9 These aberrations are more common in chromosome 1 than in chromosome 16 and only infrequently observed in chromosome 9.5 8 9 We describe an unusual primary culture from a chorionic villus (CV) biopsy in which a high frequency of ICF-like chromosomal abnormalities was observed. However, follow up indicated that the infant did not have ICF. A 30 year old, gravida 4, para 0, ab 3 white female was referred for genetic counselling and CV sampling because of a previous pregnancy with trisomy 13. Both the patient and her husband were phenotypically normal and healthy apart from their reproductive history. The patient's first two pregnancies ended in spontaneous abortion at 15 and 10 weeks. No fetal studies had been performed; parental chromosomes were analysed and reported to be normal. The third pregnancy was found to be affected with trisomy 13 (47,XY,+13) and was then terminated. During the fourth pregnancy, the patient was offered and …