Common diagnoses and factors associated with abnormal neuroimaging in headache patients in the emergency department.

OBJECTIVES: To determine causes of headaches in patients who presented to the emergency department (ED) and underwent neuroimaging, and to determine the clinical features associated with abnormal neuroimaging. METHODS: Patients were retrospectively selected from a database between June, 2015 and May, 2019. Patients were included if they had neuroimaging requested from the ED mainly for headache. Associations between clinical characteristics and abnormal neuroimaging were assessed. RESULTS: We included 329 patients (33.4% men, 66.6% women). The mean (SD) age was 39.7 (18.4) years. Neurological signs were reported in 43.8% of the patients, head-computed tomography was requested in 79.6%, magnetic resonance imaging in 77.5%, and both in 57.1%. Abnormal neuroimaging was reported in 31.9%. The most common reported diagnoses were secondary headache disorders (48.9%), followed by primary headache disorders (16.4%). The remainder were nonspecific-headaches (35%). Variables associated with abnormal neuroimaging were headache onset ≤1 month (OR 3.37, CI 1.47-7.70, p=0.004), and presence of an abnormal neurological sign (OR 3.60, CI 1.89-6.83, p<0.001). CONCLUSION: Secondary headache disorders are common in patients who undergo neuroimaging in the ED. Those who have a neurological sign and recent onset of headache are more likely to have abnormal neuroimaging.

Performance of dialysis patients on the standard and basic Arabic versions of the Montreal Cognitive Assessments.

OBJECTIVES: To assess cognitive performance in Saudi patients on dialysis using Arabic versions of the Montreal Cognitive Assessment (MoCA) and assess the reliability of the scales. METHODS: We performed a cross-sectional study at the dialysis unit of King Saud University Medical City, Riyadh from April 2019 to March 2020. Patients ≥ 18 years of age with no history of dementia underwent cognitive assessment with the standard (MoCA-A) and basic (MoCA-B) Arabic versions, with repeat testing in a subset of participants. RESULTS: Recruitment included 83 participants, 56 on hemodialysis (HD) and 27 on peritoneal dialysis (PD). The mean±SD for age was 49.99 (15.48), and for years of education was 10.29 (5.5). The mean score for MoCA-A was 21.03±5.35, and for MoCA-B was 23.45±5.14. Younger age, longer years of education and peritoneal dialysis were significantly associated with higher MoCA scores on both versions (p<0.05). The ICC was 0.81 (95% CI 0.65, 0.91) and 0.77 (95% CI 0.58, 0.89) for MoCA-A and MoCA-B, respectively. The performance on the executive and calculation tasks were higher in the PD group on the MoCA-B. The recall mean score was higher in the PD group on the MoCA-A. CONCLUSION: The HD patients are at higher risk for cognitive impairment compared to PD patients. Age and education are important variables influencing performance. Both Arabic versions of the MoCA are reliable screening tools.

Clinical features and outcome of Guillain-Barre syndrome in Saudi Arabia: a multicenter, retrospective study.

BACKGROUND: Guillain-Barre syndrome (GBS) is an inflammatory polyradiculoneuropathy characterized by rapidly evolving weakness and areflexia, reaching nadir within 4 weeks. Data on the characteristic of GBS in Saudi Arabia are limited. This study aimed to describe the clinical, electrophysiological, and laboratory characteristics and outcome of a multicenter cohort of patients with GBS. METHODS: This is a retrospective multicenter nationwide study. Patients who had GBS, identified through Brighton Criteria, between January 2015 and December 2019 were included. Data collected included demographics, clinical features, cerebrospinal fluid profile, reported electrophysiological patterns, treatment, and outcome. Reported GBS subtypes were compared using chi-square, Fisher's exact, or Mann-Whitney U tests, as appropriate. RESULTS: A total of 156 patients with GBS were included (men, 61.5%), with a median age of 38 (interquartile range, 26.25-53.5) years. The most commonly reported antecedent illnesses were upper respiratory tract infection (39.1%) and diarrhea (27.8%). All but two patients (98.7%) had weakness, 64.1% had sensory symptoms, 43.1% had facial diplegia, 33.8% had oropharyngeal weakness, 12.4% had ophthalmoplegia, and 26.3% needed mechanical ventilation. Cytoalbuminological dissociation was observed in 69.1% of the patients. GBS-specific therapy was administered in 96.8% of the patients, of whom 88.1% had intravenous immunoglobulin, and 11.9% had plasmapheresis. Approximately half of the patients were able to walk independently within 9 months after discharge, and a third regained the ability to walk independently thereafter. Death of one patient was caused by septicemia. Acute inflammatory demyelinating polyradiculoneuropathy was the most commonly reported GBS subtype (37.7%), followed by acute motor axonal neuropathy (29.5%), and acute motor-sensory axonal neuropathy (19.2%). CONCLUSION: The clinical and laboratory characteristics and outcome of GBS in the Arab population of Saudi Arabia are similar to the international cohorts. The overall prognosis is favorable.

Exacerbation Rate in Generalized Myasthenia Gravis and Its Predictors.

OBJECTIVE: The aim of the study was to estimate the exacerbation incidence rate (IR) in acetylcholine receptor antibody (AChR)-positive generalized myasthenia gravis (MG) and its predictors. METHODS: The primary outcome in this retrospective study was to estimate moderate-to-severe (M-S) exacerbations IR in the early course of generalized MG. The secondary outcome was to explore the predictors of MG exacerbations. RESULTS: Between 1999 and 2015, we identified 78 AChR-positive generalized MG patients and 37 M-S exacerbations over the first 6 years following the onset of generalized MG symptoms. The M-S exacerbation IR was 12.2 per 100 person years (95% confidence interval [CI] 8.8-16.8). Any exacerbation (including mild) IR was 24.4 per 100 person years (95% CI 19.4-30.7). After controlling for confounding factors, MG exacerbation IR predictors included gender, disease severity at onset, and prednisone dose reduction with risk ratio of 0.34 (male gender), 2.67, and 20.8, respectively (all p values <0.05). M-S exacerbation occurred in 25 cases (32.1%), while any exacerbation (mild or M-S) was detected in 45 cases (57.7%). CONCLUSION: More than half of newly diagnosed AChR + MG cases experience an exacerbation in the first 6 years. Gender, disease severity at onset and prednisone dose reduction are predictors that could inform clinical practice and future research.

Severity and depression can impact quality of life in patients with myasthenia gravis.

BACKGROUND: The revised 15-item Myasthenia Gravis (MG) Quality of Life Questionnaire (MGQoL15R) is a validated scale of quality of life in patients with MG. We aimed to study the factors causing the variability within the Arabic version of the MGQoL15R (MGQoL15R-A). METHOD: A standardized questionnaire was completed by 118 patients. Correlations and hierarchical regression analyses were used to assess the contribution of sociodemographic variables, clinical factors, Patient Health Questionnaire-9 (PHQ9-A), and Generalized Anxiety Disorder-7 (GAD7-A) to the variability in the MGQoL15R-A. RESULTS: The MGQoL15R-A was highly correlated with PHQ9-A (r = 0.76), and moderately correlated with GAD7-A (r = 0.52). Clinical factors and PHQ9-A independently explained 30.4% and 34.5% of the variability, respectively. Among the clinical factors, uncontrolled MG status, relapse within the past year, and a higher number of current MG therapies were significantly associated with a higher MGQoL15R-A score. CONCLUSIONS: MG severity and depressive symptoms (measured by PHQ9-A) can affect the MGQoL15R-A score.

Electrodiagnostic reference data for sensory nerve conduction studies in Saudi Arabia.

OBJECTIVE: To estimate reference data for the commonly performed sensory nerve conduction studies (NCS) using a cohort of healthy subjects from Saudi Arabia. METHODS: This is a cross-sectional study conducted between May 2015, and June 2019. Sensory nerve action potential (SNAP) amplitude, conduction velocity (CV), and peak latency (PL) were recorded. Associations between these parameters and the covariates (age, sex, height, weight, and body mass index) were tested with Pearson correlations. Reference data were then derived using the lowest percentile that could be reliably determined for SNAP amplitude and CV. Reference data were derived using the highest percentile for PL. RESULTS: Upper and lower limb sensory NCS were performed in 127 and 137 participants, respectively. Age was the only covariate that required adjustment for estimation of SNAP amplitude. Therefore, a prediction model was generated for each nerve. Percentile estimation for PL and CV did not require adjustment for any of the covariates. Hence, it was derived for all the subjects pooled together. CONCLUSION: The sensory NCS reference data were comparable to the data from other countries. However, minimal differences were observed. Further studies are required with a focus on the older age group.

Electrodiagnostic reference data for motor nerve conduction studies in Saudi Arabia.

OBJECTIVE: To determine nerve conduction studies (NCS) reference data for motor nerves and F-waves in the upper and lower limbs of healthy subjects in Saudi Arabia. METHODS: This is a cross-sectional study conducted between May 2015 and June 2019. Healthy subjects without neurological or systemic diseases were recruited. Motor NCS were performed following a standard protocol. Pearson correlations were employed between NCS parameters and age, gender, height, weight, and body mass index. Reference data were generated using the percentile method. RESULTS: A total of 127 subjects were recruited for the upper limb studies and 137 for the lower limb studies. Quantile regression models were generated to estimate compound muscle action potential amplitude (adjusted for age), as well as F-wave minimal latency (adjusted for height). The estimated reference limits of distal motor latency (ms) and conduction velocity (m/s) for the different nerves were, respectively, 3.7 and 50 for the median nerve, 3.3 and 50 for the ulnar nerve, 5.8 and 40 for the tibial nerve, and 5.0 and 40 for the fibular nerve. CONCLUSION: The reference data for motor NCS parameters and F-wave minimal latency are generally comparable with those of Western countries. However, minimal differences were observed. The underrepresentation of the older age group warrants future studies. The reference data for motor NCS parameters and F-wave minimal latency are generally comparable with those of Western countries. However, minimal differences were observed. The underrepresentation of the older age group warrants future studies.

Translation and validation of the arabic version of the myasthenia gravis activities of daily living scale.

INTRODUCTION: We translated the myasthenia gravis (MG)-specific activities of daily living (MG-ADL) scale into Arabic (MG-ADL-A) and assessed its psychometric properties. METHODS: We assessed reliability using Cronbach's α, reproducibility using the intraclass correlation coefficient, and validity using Spearman's correlations with MG composite (MGC) score, MG-specific manual muscle test (MG-MMT), and MG quality-of-life revised Arabic version (MGQOL15R-A). Differences in MG-ADL-A scores among patients with different disease severity were evaluated by using the Kruskal-Wallis test. Sensitivity to change was examined by using the Wilcoxon signed-rank test. RESULTS: We recruited 87 patients. The mean MG-ADL-A score was 3.38 ± 3.38 (α = 0.77, ICC = 0.99). The correlation coefficients between the MG-ADL-A and MGQOL15R-A, MGC, and MG-MMT were 0.63, 0.74, and 0.61, respectively (P < 0.001). The MG-ADL-A discriminated between different severity groups and was responsive to clinical improvement at follow-up. DISCUSSION: The MG-ADL-A has rigorous psychometric properties and can be used with Arabic-speaking patients with MG. Muscle Nerve 59:583-583, 2019.

Acute Paralytic Post-Bariatric Surgery Axonal Polyneuropathy: Clinical Features and Outcome.

INTRODUCTION: The syndrome of post-bariatric surgery axonal polyneuropathy (PAP) may present with various sensory and motor symptoms including paralysis. We aim to describe the diagnostic features and outcome of treatment of the acute paralytic form of PAP (acute paralytic PAP [APPAP]) as it was not described in a separate cohort previously. METHODS: We retrospectively reviewed medical charts and described the clinical, electrodiagnostic features, treatment, and outcome for patients who presented to our clinical neurophysiology unit with disabling weakness within 24 months post-bariatric surgery. The main outcome measure was the percent of patients who are able to walk independently at the last visit and comparing the group who resumed walking independently at 6 months to the group who did not, in regards to the use of intravenous immunoglobulin (IVIg). RESULTS: Thirteen patients were included (10 women and 3 men) with a mean age of 29.8 years (SD 12.5). All presented with loss of ambulation resembling Guillain-Barre Syndrome. The median time of onset was 4 months (interquartile range [IQR] 3-6) post-surgery, and the median time to weakness nadir was 3 weeks (IQR 3-3.5) with an average weight loss of 38.6 kg (SD 17.09). All patients regained their ability to ambulate; however, the ability to walk independently was achieved in 66.7% of patients. The percent of patients who were able to ambulate independently at 6 months were 16% with IVIg versus 66.7% without IVIg. CONCLUSION: The syndrome of -APPAP develops in the first-year post-bariatric surgery. The majority of patients regain independent ambulation.

Clinical features and outcomes of patients with myasthenia gravis.

OBJECTIVE: To report clinical and laboratory features and outcomes of patients with autoimmune myasthenia gravis (MG) recruited from a single center in Saudi Arabia. METHODS: We retrospectively reviewed prospectively collected data obtained from MG patients who have undergone examination and follow-up at our neuromuscular clinic between August 1, 2014 and January 31, 2019. RESULTS: Ninety-five patients (55 females) were included. The mean age of onset of MG was 40.5+/-18.1 years in males and 31.3+/-15 years in females (p=0.009). The mean duration of follow-up at our clinic was 34.7+/-14.1 months, while the mean duration since MG onset was 8.0+/-7.2 years. Of all patients, 92.6% had generalized MG, 82.1% had acetylcholine receptor (AChR) antibodies, 4.2% had muscle-specific tyrosine kinase (MuSK) antibodies, 78.9% had early-onset MG with no second peak after age of 50 years, 22.1% had myasthenia crisis, 12.6% had refractory MG, 31.6% had thymic hyperplasia, 10.5% had thymoma, and 61.1% required more than or equal 2 immunosuppressive therapies. At the last follow-up, 93 patients had achieved an optimal outcome (MG Foundation of America classification less than or equal II). No patient with double-seronegative (dSN)-MG had thymoma, needed rituximab or intravenous immunoglobulin maintenance therapy, or was classified as refractory MG. CONCLUSION: Contrary to other studies, we did not observe a second-peak of MG onset. Clinical outcomes were favorable in the majority of our patients.

Translation and validation of the Arabic version of the Boston carpal tunnel syndrome questionnaire.

OBJECTIVE: To translate and validate the Arabic version of the Boston carpal tunnel questionnaire (BCTQ-A). METHODS: We recruited consecutive patients with carpal tunnel syndrome (CTS). Reliability was assessed with Cronbach alpha, reproducibility with intraclass correlation coefficients, construct validity with factor analysis, and responsiveness post carpal tunnel release (CTR) with the Wilcoxon signed-rank test. RESULTS: In 134 patients, the mean total scores for the symptom severity scale (SSS) and functional status scale (FSS) were 32.0+/-8.4 (alpha=0.88, ICC=0.88) and 18.5+/-7.6 (alpha=0.87, ICC=0.89), respectively. As in the original Boston carpal tunnel questionnaire (BCTQ), a 3-factor model of the BCTQ-A best fitted the data. The BCTQ-A, SSS, and FSS scores were significantly lower post-CTR. CONCLUSION: The BCTQ-A is reliable, valid, reproducible, and responsive to interventions. The Arabic version can be now used with Arabic-speaking patients with CTS.

Corrigendum: Autozygosity reveals recessive mutations and novel mechanisms in dominant genes: implications in variant interpretation.

This corrects the article DOI: 10.1038/gim.2017.22.

Translation and validation of the arabic version of the revised 15-item myasthenia gravis quality-of-life questionnaire.

INTRODUCTION: We sought to translate, culturally adapt, and assess the Arabic version of the 15-item myasthenia gravis quality-of-life revised scale (MGQOL15R). METHODS: We assessed reliability with Cronbach α; reproducibility with intraclass correlation coefficient (ICC); validity with Spearman correlations for myasthenia gravis (MG)-specific activities of daily living (MG-ADL), MG composite (MGC) score, and MG manual muscle test (MG-MMT) and with MGQOL15R in patients with different disease severity through the Kruskal-Wallis test; and sensitivity to change with Wilcoxon signed-rank test. RESULTS: In 65 enrolled patients, the mean MGQOL15R score was 10.84 ± 8.11 (α = 0.94, ICC = 0.95). The correlation coefficients between MGQOL15R and MGC, MG-ADL, and MG-MMT scores were 0.75, 0.75, and 0.74, respectively (P < 0.001). MGQOL15R scores were significantly higher (worse) in patients with more severe disease at baseline and significantly lower (better) in improved patients at follow-up. DISCUSSION: The Arabic version of MGQOL15R is valid, reliable, stable, and sensitive to changes. Muscle Nerve 57: 581-585, 2018.

The conventional tuning fork as a quantitative tool for vibration threshold.

INTRODUCTION: This study was undertaken to describe a method for quantifying vibration when using a conventional tuning fork (CTF) in comparison to a Rydel-Seiffer tuning fork (RSTF) and to provide reference values. METHODS: Vibration thresholds at index finger and big toe were obtained in 281 participants. Spearman's correlations were performed. Age, weight, and height were analyzed for their covariate effects on vibration threshold. Reference values at the fifth percentile were obtained by quantile regression. RESULTS: The correlation coefficients between CTF and RSTF values at finger/toe were 0.59/0.64 (P = 0.001 for both). Among covariates, only age had a significant effect on vibration threshold. Reference values for CTF at finger/toe for the age groups 20-39 and 40-60 years were 7.4/4.9 and 5.8/4.6 s, respectively. Reference values for RSTF at finger/toe for the age groups 20-39 and 40-60 years were 6.9/5.5 and 6.2/4.7, respectively. DISCUSSION: CTF provides quantitative values that are as good as those provided by RSTF. Age-stratified reference data are provided. Muscle Nerve 57: 49-53, 2018.

Accuracy of seizure semiology obtained from first-time seizure witnesses.

BACKGROUND: Little is known of how accurately a first-time seizure witness can provide reliable details of a semiology. Our goal was to determine how accurately first-time seizure witnesses could identify key elements of an epileptic event that would aid the clinician in diagnosing a seizure. METHODS: A total of 172 participants over 17 years of age, with a mean (sd) of 33.12 (13.2) years and 49.4% female, composed of two groups of community dwelling volunteers, were shown two different seizure videos; one with a focal seizure that generalized (GSV), and the other with a partial seizure that did not generalize (PSV). Participants were first asked about what they thought was the event that had occurred. They then went through a history-taking scenario by an assessor using a battery of pre-determined questions about involvement of major regions: the head, eyes, mouth, upper limbs, lower limbs, or change in consciousness. Further details were then sought about direction of movement in the eyes, upper and lower limbs, the side of limb movements and the type of movements in the upper and lower limbs. Analysis was with descriptive statistics and logistic regression. RESULTS: One hundred twenty-two (71.4%) identified the events as seizure or epilepsy. The accuracy of identifying major areas of involvement ranged from 60 to 89.5%. Horizontal head movements were significantly more recognized in the PSV, while involvement of the eyes, lateralization of arm movement, type of left arm movement, leg involvement, and lateralization of leg movement were significantly more recognized in the GSV. Those shown the GSV were more likely to recognize the event as "seizure" or "epilepsy" than those shown the PSV; 78 (84.8%) vs 44 (55.7%), (OR 0.22, p < 0.0001). Younger age was also associated with correct recognition (OR 0.96, P 0.049). False positive responses ranged from 2.5 to 32.5%. CONCLUSION: First-time witnesses can identify important elements more than by chance alone, and are more likely to associate generalized semiologies with seizures or epilepsy than partial semiologies. However, clinicians still need to navigate the witness's account carefully for additional information since routine questioning could result in a misleading false positive answer.

Migraine and Headache Prevalence and Associated Comorbidities in a Large Saudi Sample.

BACKGROUND: We aimed to assess the prevalence of headache and migraine, along with comorbidities, in a large -Saudi sample. METHODS: Self-reported information was collected about headache, migraine and migraine comorbidities including depression, restless legs syndrome (RLS), syncope, bruxism, hypertension and ischaemic disease. The OR was estimated using logistic regression for any associations with headache and migraine. We then analyzed to find a trend of increasing migraine symptoms for each significant comorbidity. RESULTS: Out of 4,943 respondents, 4,158 (84.12%) had recurring headaches. Migraine was present in 1,333 (26.97%), with female predominance (ratio of 1: 2.9). There were statistically significant ORs between migraine and female sex, current smokers, higher income, hypertension, depression, syncope, RLS and bruxism. Non-migraine headaches were significantly associated with female sex, age, RLS and ischaemic disease. Migraine with aura was significantly associated with syncope, ischaemic disease, higher income and BMI. There was an overall significant trend of increasing migraine features in the presence of depression, syncope, RLS, bruxism and hypertension. CONCLUSIONS: Headache in general and migraine in particular are associated with multiple comorbidities in comparison to non-headache participants in our cohort, with an estimated prevalence similar to that of western countries.

The Role of Demographic and Symbolic Features in Clinical Arabic Graphesthesia Testing.

OBJECTIVE: Graphesthesia is the ability to identify a symbol traced on the skin. Agraphesthesia is the impairment in this ability and is encountered in various disorders of the somatosensory pathways. We aimed to describe the demographic and symbolic features that influence correct recognition of Arabic graphesthesia stimuli in healthy Arabic individuals. METHODS: Participants were community dwelling healthy Arabian individuals of 18 years of age or older. Demographic information collected included age, gender, years of education, and hand dominance. Assessment was conducted using a list of 15 symbols drawn in a single stroke while the hands were obscured from vision. Symbols were current letters and numbers from Arabic script. Each participant was exposed to 60 attempts in total in a random order and correct responses were counted. RESULTS: A total of 126 male and female participants were included. On average, men scored less than women (p < 0.0001), older subjects scored less than those below 30 years of age (p = 0.03), and higher years of education resulted in higher scores (p = 0.047) while handedness did not significantly associate with performance. More correct responses were seen for numerical symbols than letters (p < 0.0001). Symbols with unique script were more likely to be correctly identified. CONCLUSIONS: Number and letter symbols traced on the palm are identified with varying levels of accuracy when conducted according to our method. Female gender, younger age, and higher education are associated with higher scores. Among the many potential symbolic properties that contribute to recognition, a numeric symbol with a unique script is most likely to be correctly identified.

Multiple sclerosis and myasthenia gravis following severe weight loss.

Weight loss has substantial health benefits, but it is not risk-free. Various neurological disorders have been reported following bariatric surgery-induced weight loss. Here, we report 3 patients who developed multiple sclerosis (MS), one of whom also developed myasthenia gravis (MG), shortly after significant weight loss. Two patients lost weight by following a diet plan and one underwent bariatric surgery. There may be an association between significant weight loss and the development of an autoimmune neurological disorder such as MS or MG; a high index of suspicion is required.

Epilepsy monitoring units in Saudi Arabia: Where do we stand compared to developed countries?

OBJECTIVE: To descriptively assess Epilepsy Monitoring Units (EMUs) and the provided services in Saudi Arabia and compare them based on the geographic region. METHODS: In this cross-sectional study, an electronic questionnaire was emailed to all directors of EMUs in Saudi Arabia from July 2013 to January 2016, with constant updates being made by all respondents throughout the period of data collection. RESULTS: All EMU directors participated. There were 11 EMUs in KSA operating in 8 hospitals; 8 (54.5%) EMUs in Riyadh, 2 (18.2%) in Dammam, 2 (18.2%) in Makkah and 1 (9.1%) in Jeddah. Five (54.5%) EMUs were shared for adults and pediatrics, 3 (27.3%) were devoted to adult patients, and 3 (27.3%) to pediatric patients. The average waiting time was 11 weeks (range: 2-52 weeks). The mean percentage of patients coming from an outside region was 30.6%. The average length of stay was 7 days. Less than 100 patients were monitored annually in 54.5% of the EMUs. Seven EMUs (63.6%) admitted less than 100 patients for seizure characterization. Intracranial monitoring was available in all EMUs. Most EMUs (54.5%) admitted less than 100 patients for pre-surgical workup while 36.4% admitted 100-199, and 9.1% admitted more than 300 patients per year. Epilepsy surgeries were performed for less than 50 patients annually in 81.8% of the hospitals. CONCLUSION: There are 11 EMUs in Saudi Arabia fully equipped to serve epileptic patients. However, they are underutilized considering the number of admitted patient and the number of epilepsy surgeries per year. Also, they are unequally distributed throughout the kingdom.

Autozygosity reveals recessive mutations and novel mechanisms in dominant genes: implications in variant interpretation.

PURPOSE: The purpose of this study is to describe recessive alleles in strictly dominant genes. Identifying recessive mutations in genes for which only dominant disease or risk alleles have been reported can expand our understanding of the medical relevance of these genes both phenotypically and mechanistically. The Saudi population is enriched for autozygosity, which enhances the homozygous occurrence of alleles, including pathogenic alleles in genes that have been associated only with a dominant inheritance pattern. METHODS: Exome sequencing of patients from consanguineous families with likely recessive phenotypes was performed. In one family, the genotype of the deceased children was inferred from their parents due to lack of available samples. RESULTS: We describe the identification of 11 recessive variants (5 of which are reported here for the first time) in 11 genes for which only dominant disease or risk alleles have been reported. The observed phenotypes for these recessive variants were novel (e.g., FBN2-related myopathy and CSF1R-related brain malformation and osteopetrosis), typical (e.g., ACTG2-related visceral myopathy), or an apparently healthy state (e.g., PDE11A), consistent with the corresponding mouse knockout phenotypes. CONCLUSION: Our results show that, in the era of genomic sequencing and "reverse phenotyping," recessive variants in dominant genes should not be dismissed based on perceived "incompatibility" with the patient's phenotype before careful consideration.Genet Med advance online publication 06 April 2017.