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Thousand and one amino‐acid kinase 1 (TAOK1) is a MAP3K protein kinase, regulating different mitogen‐activated protein kinase pathways, thereby modulating a multitude of processes in the cell. Given the recent finding of TAOK1 involvement in neurodevelopmental disorders (NDDs), we investigated the role of TAOK1 in neuronal function and collected a cohort of 23 individuals with mostly de novo variants in TAOK1 to further define the associated NDD. Here, we provide evidence for an important role for TAOK1 in neuronal function, showing that altered TAOK1 expression levels in the embryonic mouse brain affect neural migration in vivo, as well as neuronal maturation in vitro. The molecular spectrum of the identified TAOK1 variants comprises largely truncating and nonsense variants, but also missense variants, for which we provide evidence that they can have a loss of function or dominant‐negative effect on TAOK1, expanding the potential underlying causative mechanisms resulting in NDD. Taken together, our data indicate that TAOK1 activity needs to be properly controlled for normal neuronal function and that TAOK1 dysregulation leads to a neurodevelopmental disorder mainly comprising similar facial features, developmental delay/intellectual disability and/or variable learning or behavioral problems, muscular hypotonia, infant feeding difficulties, and growth problems., In this study we expand the cohort of individuals with a neurodevelopmental disorder, carrying a de novo variant in TAOK1 (a), thereby further defining the neurodevelopmental disorder caused by TAOK1 malfunctioning. Using both in vivo (b) and in vitro (c) functional assays, we provide evidence that increased as well as decreased levels of TAOK1 cause disruption of neuronal development, showing that TAOK1 plays an important role in neuronal function. Additionally, our data suggests that both gain of function as well as loss of function mutations are potentially causative for the TAOK1‐related neurodevelopmental disorder.

BACKGROUND AND AIMS The risk for hepatocellular carcinoma (HCC) is increased in acute hepatic porphyrias (AHP). The aim of this study was to explore the clinicopathologic characteristics, outcomes, and frequency of HCC in patients with AHP in the United States. APPROACH AND RESULTS This cross-sectional analysis evaluated patients with HCC in a multicenter, longitudinal study of AHP. Among 327 patients with AHP, 5 (1.5%) were diagnosed with HCC. Of the 5 HCC cases, 4 had acute intermittent porphyria and 1 had variegate porphyria, confirmed by biochemical and/or genetic testing. All patients were white females, with a median age of 27 years (range 21-75) at diagnosis. The median age at HCC diagnosis was 69 years (range 61-74). AHP was asymptomatic in 2 patients; 2 reported sporadic attacks; and 1 reported recurrent attacks (>4 attacks/year). All patients had a single HCC lesion on liver imaging that was 1.8-6.5 centimeters in diameter. Serum alpha fetoprotein levels were below 10 ng/mL in all 4 patients with available results. Four patients underwent liver resection, and 1 was treated with radioembolization. No significant inflammation or fibrosis was found in adjacent liver tissues of 3 patients who underwent liver resection. Two patients developed recurrence of HCC at 22 and 26 months following liver resection. All patients are alive with survival times from HCC diagnosis ranging from 26-153 months. CONCLUSION In this U.S. study, 1.5% of patients with AHP had HCC. HCC in AHP occurred in the absence of cirrhosis, which contrasts with other chronic liver diseases. Patients with AHP, regardless of clinical attacks, should be screened for HCC, beginning at age 50. The pathogenesis of hepatocarcinogenesis in AHP is unknown and needs further investigation.

PURPOSE: This study aimed to describe the phenotypic and molecular characteristics of ARCN1-related syndrome. METHODS: Patients with ARCN1 variants were identified, and clinician researchers were connected using GeneMatcher and physician referrals. Clinical histories were collected from each patient. RESULTS: In total, we identified 14 cases of ARCN1-related syndrome, (9 pediatrics, and 5 fetal cases from 3 families). The clinical features these newly identified cases were compared to 6 previously reported cases for a total of 20 cases. Intrauterine growth restriction, micrognathia, and short stature were present in all patients. Other common features included prematurity (11/15, 73.3%), developmental delay (10/14, 71.4%), genitourinary malformations in males (6/8, 75%), and microcephaly (12/15, 80%). Novel features of ARCN1-related syndrome included transient liver dysfunction and specific glycosylation abnormalities during illness, giant cell hepatitis, hepatoblastoma, cataracts, and lethal skeletal manifestations. Developmental delay was seen in 73% of patients, but only 3 patients had intellectual disability, which is less common than previously reported. CONCLUSION: ARCN1-related syndrome presents with a wide clinical spectrum ranging from a severe embryonic lethal syndrome to a mild syndrome with intrauterine growth restriction, micrognathia, and short stature without intellectual disability. Patients with ARCN1-related syndrome should be monitored for liver dysfunction during illness, cataracts, and hepatoblastoma. Additional research to further define the phenotypic spectrum and possible genotype–phenotype correlations are required.

Background: Acute Intermittent Porphyria (AIP) is a rare inborn error of heme biosynthesis characterized clinically by life-threatening acute neurovisceral attacks. Few studies have assessed quality of life (QoL) tools in the AIP population, and none are validated for use in AIP. In this study, the Patient Reported Outcomes Measurement Information System 57 (PROMIS-57) scales were assessed in AIP patients to determine the factor structure of PROMIS items and to compare this to previously proposed factor structures in the general population.Methods: Baseline data from the Porphyrias Consortium’s Longitudinal Study of the Porphyrias was obtained for 259 AIP patients. This included detailed disease and medical history information as well as PROMIS-57 data. Exploratory and confirmatory factor analyses (EFA and CFA, respectively) were conducted on baseline PROMIS-57 data. CFA was used to test the hypothesized three-factor structure from the PROMIS literature. Results: Internal consistency was high for all the PROMIS scales assessed. The EFA revealed a five-factor model, each consisting of a separate domain: pain interference, anxiety, depression, sleep disturbance, and fatigue. Model fit was good overall. A CFA of the hypothesized three-factor model did not converge suggesting an inappropriate structural model. Conclusion: The EFA showed a five-factor model that fit the data well, however a CFA of the three-factor model observed in the general population did not fit the data well. These findings, together with previous studies assessing correlations with clinical features, indicate that the PROMIS scales may be valid and reliable measures for AIP patients. However, further analyses are needed to confirm this. Further studies should assess correlations with other tools, whether the PROMIS scales are responsive to treatment, if they capture QoL longitudinally, and a CFA in a second sample.

Distal deletions and duplications of 3p are individually well-characterized chromosome abnormalities. Here, we report an inverted duplication of 3p with an adjacent terminal 3p deletion in a 17-month-old girl who had prenatal intrauterine growth restriction and cardiac defects. Other findings included hemangiomas, neutropenia, umbilical hernia, hypotonia, gross motor delay, microcephaly, and ptosis. Family history was noncontributory. Microarray analysis revealed a 5.37 Mb deletion of chromosome bands 3p26.1 to 3p26.3 and a 13.68 Mb duplication of 3p24.3 to 3p26.1. FISH analysis confirmed that the duplication was inverted. Upon literature review, only one postnatal patient and one second trimester pregnancy have been reported with this finding. Many of our patient’s features are present in both 3p deletion and 3p duplication syndromes, including congenital heart disease, growth restriction, microcephaly, hypotonia, and developmental delay. Our patient has additional features not commonly reported in 3p deletion or duplication patients, such as aortic dilation, hemangiomas, and neutropenia. The identification of this patient contributes to additional understanding of features associated with concurrent deletion and inverted duplication in the distal 3p chromosome. This report may assist clinicians working with patients who have constellations of similar features or similar cytogenomic abnormalities.

Acute intermittent porphyria (AIP), an autosomal dominant disorder due to the half-normal activity of hydroxymethylbilane synthase (HMBS), is characterized by acute neurovisceral attacks that are precipitated by factors that induce heme biosynthesis. Molecular diagnosis is the most sensitive and specific diagnostic test for AIP, and importantly, it permits the identification of asymptomatic family members for genetic counseling and avoidance of precipitating factors. Here, we report the identification of 40 novel HMBS mutations, including 11 missense, four nonsense, 16 small insertions or deletions, eight consensus splice site mutations, and a complex insertion-deletion mutation in unrelated individuals with AIP. Prokaryotic expression of the missense mutations demonstrated that all mutants had ≤5% of expressed wildtype activity, except for c.1039G>C (p.A347P), which had 51% residual HMBS activity but was markedly thermolabile. Of note, the mutation c.612G>T (p.Q204H) altered the last nucleotide of exon 10, which resulted in an alternative HMBS transcript with an in-frame nine base-pair deletion at the 3'-terminus of exon 10 (encoding protein Q204HΔ3). When expressed, Q204HΔ3 and an in-frame three base-pair deletion (c.639_641delTGC) had no detectable HMBS activity. Western blot analyses and mapping of the missense mutations on the human HMBS crystal structure revealed that mutations near the active site or at the dimerization interface resulted in stably expressed proteins, while most that altered surface residues resulted in unstable proteins, presumably due to improper protein folding. These studies identified novel pathogenic HMBS mutations and expanded the molecular heterogeneity of AIP.

PurposeAcute intermittent porphyria (AIP) is a rare inborn error of heme biosynthesis characterized by life-threatening acute attacks. Few studies have assessed quality of life (QoL) in AIP and those that have had small sample sizes and used tools that may not have captured important domains.MethodsBaseline data from the Porphyrias Consortium's Longitudinal Study were obtained for 259 patients, including detailed disease and medical history data, and the following Patient-Reported Outcomes Measurement Information System (PROMIS) scales: anxiety, depression, pain interference, fatigue, sleep disturbance, physical function, and satisfaction with social roles. Relationships between PROMIS scores and clinical and biochemical AIP features were explored.ResultsPROMIS scores were significantly worse than the general population across all domains, except depression. Each domain discriminated well between asymptomatic and symptomatic patients with symptomatic patients having worse scores. Many important clinical variables like symptom frequency were significantly associated with domain scores in univariate analyses, showing responsiveness of the scales, specifically pain interference and fatigue. However, most regression models only explained ~20% of the variability observed in domain scores.ConclusionPain interference and fatigue were the most responsive scales in measuring QoL in this AIP cohort. Future studies should assess whether these scales capture longitudinal disease progression and treatment response.

Gross deletions involving the MEIS2 gene have been described in a small number of patients with overlapping phenotypes of atrial or ventricular septal defects, cleft palate, and variable developmental delays and intellectual disability. Non-specific dysmorphic features were noted in some patients, including broad forehead with high anterior hairline, arched eyebrows, thin or tented upper lip, and short philtrum. Recently, a patient with a de novo single amino acid deletion, c.998_1000delGAA (p.Arg333del), and a patient with a de novo nonsense variant, (c.611C>G, p.Ser204*), were reported with a similar, but apparently more severe phenotypes. Clinical whole exome sequencing (WES) performed at our clinical molecular diagnostic laboratory identified four additional patients with predicted damaging de novo MEIS2 missense variants. Our patients' features closely resembled those previously reported in patients with gross deletions, but also included some less commonly reported features, such as autism spectrum disorder, hearing loss, and short stature, as well as features that may be unique to nucleotide-level variants, such as hypotonia, failure to thrive, gastrointestinal, skeletal, limb, and skin abnormalities. All of the observed missense variants, Pro302Leu, Gln322Leu, Arg331Lys, and Val335Ala, are located in the functionally important MEIS2 homeodomain. Pro302Leu is found in the region between helix 1 and helix 2, while the other three are located in the DNA-binding helix 3. To our knowledge, these are the first described de novo missense variants in MEIS2, expanding the known mutation spectrum of the newly recognized human disorder caused by aberrations in this gene.

Whole exome sequencing (WES) has the potential of identifying secondary findings that are predictive of poor pharmacotherapy outcomes. The purpose of this study was to investigate patients’ wishes regarding the reporting of secondary pharmacogenomic findings. WES results (n = 106 patients) were retrospectively reviewed to determine the number of patients electing to receive secondary pharmacogenomic results. Phenotypes were assigned based on Clinical Pharmacogenetics Implementation Consortium (CPIC) guidelines. The percent of patients with a predicted phenotype associated with a gene-based CPIC dosing recommendation was determined. Ninety-nine patients (93.4%) elected to receive secondary pharmacogenomic findings. For each gene–drug pair analyzed, the number of patients with an actionable phenotype ranged from two (2%) to 43 patients (43.4%). Combining all gene–drug pairs, 84 unique patients (84.8%) had an actionable phenotype. A prospective multidisciplinary practice model was developed for integrating secondary pharmacogenomic findings into clinical practice. Our model highlights a unique collaboration between physician-geneticists, pharmacists, and genetic counselors.

Background and Aims: Patatin-like phospholipase domain protein 3 (PNPLA3) polymorphisms (rs738409 C>G) are associated with non-alcoholic fatty liver disease (NAFLD). We performed a systematic review and meta-analysis to examine the association of PNPLA3 polymorphisms with the spectrum and severity of this disease. Methods: Studies evaluating the association between the PNPLA3 polymorphism spectrum (fatty liver, steatohepatitis, cirrhosis, and hepatocellular carcinoma) and NAFLD were included. Pooled data are reported as odds ratios (ORs) with 95% confidence intervals. Results: Of 393 potentially relevant studies, 35 on NAFLD were included in the analysis. Compared to healthy controls, the pooled ORs for rs738409 CG and GG compared to CC among patients with non-alcoholic fatty liver (NAFL) were 1.46 (1.16–1.85) and 2.76 (2.30–3.13), and were 1.75 (1.24–2.46) and 4.44 (2.92–6.76) among patients with non-alcoholic steatohepatitis respectively. The respective ORs for CG and GG compared to the CC genotype were 2.35 (0.90–6.13) and 5.05 (1.47–17.29) when comparing non-alcoholic hepatocellular carcinoma to NAFL patients. Among the NAFLD patients, the ORs for G allele frequency when comparing steatosis grade 2–3 to grade 0–1 NAFL, when comparing the NAFLD activity score of ≥ 4 to score ≤ 3, when comparing NASH to NAFLD, when comparing the presence of lobular inflammation to absence, and when comparing the presence of hepatocyte ballooning to absence were 2.33 (1.43–3.80), 1.80 (1.36–2.37), 1.66 (1.42–1.94), 1.58 (1.19–2.10), and 2.63 (1.87–3.69) respectively. Subgroup analysis based on ethnicity showed similar results. Conclusions: PNPLA3 polymorphisms have strong association with the risk for and severity of NAFLDs. PNPLA3 polymorphism plays an evolving role in diagnosis and treatment decisions in patients with NAFLD.

Congenital erythropoietic porphyria (CEP) is a rare autosomal recessive disorder characterized by photosensitivity and by hematologic abnormalities in affected individuals. CEP is caused by mutations in the uroporphyrinogen synthase (UROS) gene. In three reported cases, CEP has been associated with a specific X-linked GATA1 mutation. Disease-causing mutations in either gene result in absent or markedly reduced UROS enzymatic activity. This in turn leads to the accumulation of the non-physiologic and photoreactive porphyrinogens, uroporphyrinogen I and coproporphyrinogen I, which damage erythrocytes and elicit a phototoxic reaction upon light exposure. The clinical spectrum of CEP depends on the level of residual UROS activity, which is determined by the underlying pathogenic loss-of-function UROS mutations. Disease severity ranges from non-immune hydrops fetalis in utero to late-onset disease with only mild cutaneous involvement. The clinical characteristics of CEP include exquisite photosensitivity to visible light resulting in bullous vesicular lesions which, when infected lead to progressive photomutilation of sun-exposed areas such as the face and hands. In addition, patients have erythrodontia (brownish discoloration of teeth) and can develop corneal scarring. Chronic transfusion-dependent hemolytic anemia is common and leads to bone marrow hyperplasia, which further increases porphyrin production. Management of CEP consists of strict avoidance of exposure to visible light with sun-protective clothing, sunglasses, and car and home window filters. Adequate care of ruptured vesicles and use of topical antibiotics is indicated to prevent superinfections and osteolysis. In patients with symptomatic hemolytic anemia, frequent erythrocyte cell transfusions may be necessary to suppress hematopoiesis and decrease marrow production of the phototoxic porphyrins. In severe transfection-dependent cases, bone marrow or hematopoietic stem cell transplantation has been performed, which is curative. Therapeutic approaches including gene therapy, proteasome inhibition, and pharmacologic chaperones are under investigation.

The genetic polymorphism with an isoleucine-to-methionine substitution at position 148 (rs738409 CG) in the patatin-like phospholipase domain protein 3 (PNPLA3) gene confers risk of steatosis. PNPLA3 polymorphism is shown to be associated with alcoholic liver disease (ALD). We performed a systematic review and meta-analysis to examine association of this genetic polymorphism with ALD spectrum and its severity.Medline, Embase, and Cochrane Library were searched for studies on association of PNPLA3 polymorphism and ALD spectrum: alcoholic fatty liver (AFL), alcoholic liver injury (ALI), alcoholic cirrhosis (AC), and hepatocellular carcinoma (HCC). Pooled data are reported as odds ratio (OR) with 95% confidence interval. Heterogeneity was assessed using the I(2) statistics and publication bias using Egger's test and Begg and Mazumdar's test. Individual participant data obtained from five studies were used for subgroup analyses.Among 10 studies included in this pooled analysis, compared with controls, OR for rs738409 CG and GG among ALI patients was 1.45 (1.24-1.69) and 2.22 (1.50-3.28), respectively, compared with CC. Respective OR among AC patients was 2.09 (1.79-2.44) and 3.37 (2.49-4.58) and among AC patients with HCC was 2.87 (1.61-5.10) and 12.41 (6.99-22.03). Data for AFL were inconsistent. Among ALD patients, OR of CG and GG genotypes was 2.62 (1.73-3.97) and 8.45 (2.52-28.37), respectively, for AC compared with fatty liver (FL) patients. Similar OR for AC compared with ALI was 1.98 (1.24-3.17) and 3.86 (1.18-12.60). The OR for CG and GG genotypes among AC patients for HCC occurrence was 1.43 (0.76-2.72) and 2.81 (1.57-5.01), respectively. Individual participant data analysis showed age to predispose to AC among ALI patients.PNPLA3 genetic polymorphism (rs738409 CG) is associated with increased risk for the entire spectrum of ALD among drinkers including ALI, AC, and HCC. Studies are needed to clarify association of PNPLA3 polymorphism and steatosis in alcoholics. PNPLA3 gene may potentially be a therapeutic target in ALD.

Lysosomal acid lipase deficiency (LALD) is a lysosomal storage disorder (LSD) characterized either by infantile onset with fulminant clinical course and very poor prognosis or childhood/adult-onset disease with an attenuated phenotype. The disorder is often misdiagnosed or remains undiagnosed in children and adults due to a rather unspecific clinical presentation with dyslipidemia and steatohepatitis. Until recently, no good treatment options were available for LALD. Despite supportive and symptomatic therapies, death occurred before 1 year of age in patients with infantile-onset disease and patients with childhood/adult-onset LALD suffered from significant complications, such as liver cirrhosis, requiring liver transplantation and early-onset cardiovascular disease.With the recent approval of sebelipase alfa for clinical use in infantile- as well as childhood/adult-onset LALD, a new treatment era for this disorder has begun. Sebelipase alfa is a recombinant human lysosomal acid lipase (LAL), which is administered via the intravenous route. Clinical trials have shown significant improvement of disease parameters such as liver transaminases, hepatomegaly, and dyslipidemia in childhood/adult-onset LALD patients. Treatment of infants with the severe infantile-onset form of the disease has led to improved survival beyond the age of 1 year, and also showed improvement of hepatic and gastrointestinal symptoms, as well as growth. Overall, sebelipase alfa has a favorable safety profile and promises to be a good long-term treatment option for patients with LALD, with significant reduction of disease burden and increased life expectancy.

This study assessed physician attitudes toward adopting genome-guided prescribing through clinical decision support (CDS), prior to enlisting in the Clinical Implementation of Personalized Medicine through Electronic Health Records and Genomics pilot pharmacogenomics project (CLIPMERGE PGx). We developed a survey instrument that includes the Evidence Based Practice Attitude Scale, adapted to measure attitudes toward adopting genome-informed interventions (EBPAS-GII). The survey also includes items to measure physicians’ characteristics (awareness, experience, and perceived usefulness), attitudes about personal genome testing (PGT) services, and comfort using technology. We surveyed 101 General Internal Medicine physicians from the Icahn School of Medicine at Mount Sinai (ISMMS). The majority were residency program trainees (~88%). Prior to enlisting into CLIPMERGE PGx, most physicians were aware of and had used decision support aids. Few physicians, however, were aware of and had used genome-guided prescribing. The majority of physicians viewed decision support aids and genotype data as being useful for making prescribing decisions. Most physicians had not heard of, but were willing to use, PGT services and felt comfortable interpreting PGT results. Most physicians were comfortable with technology. Physicians who perceived genotype data to be useful in making prescribing decisions, had more positive attitudes toward adopting genome-guided prescribing through CDS. Our findings suggest that internal medicine physicians have a deficit in their familiarity and comfort interpreting and using genomic information. This has reinforced the importance of gathering feedback and guidance from our enrolled physicians when designing genome-guided CDS and the importance of prioritizing genomic medicine education at our institutions.

The number of clinically relevant gene-based guidelines and recommendations pertaining to drug prescribing continues to grow. Incorporating gene-drug interaction information into the drug-prescribing process can help optimize pharmacotherapy outcomes and improve patient safety. However, pharmacogenomic implementation barriers exist such as integration of pharmacogenomic results into electronic health records (EHRs), development and deployment of pharmacogenomic decision support tools to EHRs, and feasible models for establishing ambulatory pharmacogenomic clinics. We describe the development of pharmacist-managed pharmacogenomic services within a large health system. The Clinical Pharmacogenetics Implementation Consortium guidelines for HLA-B*57:01-abacavir, HLA-B*15:02-carbamazepine, and TPMT-thiopurines (i.e., azathioprine, mercaptopurine, and thioguanine) were systematically integrated into patient care. Sixty-three custom rules and alerts (20 for TPMT-thiopurines, 8 for HLA-B*57:01-abacavir, and 35 for HLA-B*15:02-anticonvulsants) were developed and deployed to the EHR for the purpose of providing point-of-care pharmacogenomic decision support. In addition, a pharmacist and physician-geneticist collaboration established a pharmacogenomics ambulatory clinic. This clinic provides genetic testing when warranted, result interpretation along with pharmacotherapy recommendations, and patient education. Our processes for developing these pharmacogenomic services and solutions for addressing implementation barriers are presented.

Acute intermittent porphyria (AIP) is an autosomal-dominant hepatic disorder caused by the half-normal activity of hydroxymethylbilane (HMB) synthase. Symptomatic individuals experience life-threatening acute neurovisceral attacks that are precipitated by factors that induce the hepatic expression of 5-aminolevulinic acid synthase 1 (ALAS1), resulting in the marked accumulation of the putative neurotoxic porphyrin precursors 5-aminolevulinic acid (ALA) and porphobilinogen (PBG). Here, we provide the first detailed description of the biochemical and pathologic alterations in the explanted liver of an AIP patient who underwent orthotopic liver transplantation (OLT) due to untreatable and debilitating chronic attacks. After OLT, the recipient’s plasma and urinary ALA and PBG rapidly normalized, and her attacks immediately stopped. In the explanted liver, (a) ALAS1 mRNA and activity were elevated approximately ∼3- and 5-fold, and ALA and PBG concentrations were increased ∼3- and 1,760-fold, respectively; (b) uroporphyrin III concentration was elevated; (c) microsomal heme content was sufficient, and representative cytochrome P450 activities were essentially normal; (d) HMB synthase activity was approximately half-normal (∼42%); (e) iron concentration was slightly elevated; and (f) heme oxygenase I mRNA was increased approximately three-fold. Notable pathologic findings included nodular regenerative hyperplasia, previously not reported in AIP livers, and minimal iron deposition, despite the large number of hemin infusions received before OLT. These findings suggest that the neurovisceral symptoms of AIP are not associated with generalized hepatic heme deficiency and support the neurotoxicity of ALA and/or PBG. Additionally, they indicate that substrate inhibition of hepatic HMB synthase activity by PBG is not a pathogenic mechanism in acute attacks.

Hereditary hemochromatosis (HH) is a common autosomal-recessive disorder associated with pathogenic HFE variants, most commonly those resulting in p.Cys282Tyr and p.His63Asp. Recommendations on returning incidental findings of HFE variants in individuals undergoing genome-scale sequencing should be informed by penetrance estimates of HH in unselected samples. We used the eMERGE Network, a multicenter cohort with genotype data linked to electronic medical records, to estimate the diagnostic rate and clinical penetrance of HH in 98 individuals homozygous for the variant coding for HFE p.Cys282Tyr and 397 compound heterozygotes with variants resulting in p.[His63Asp];[Cys282Tyr]. The diagnostic rate of HH in males was 24.4% for p.Cys282Tyr homozygotes and 3.5% for compound heterozygotes (p < 0.001); in females, it was 14.0% for p.Cys282Tyr homozygotes and 2.3% for compound heterozygotes (p < 0.001). Only males showed differences across genotypes in transferrin saturation levels (100% of homozygotes versus 37.5% of compound heterozygotes with transferrin saturation > 50%; p = 0.003), serum ferritin levels (77.8% versus 33.3% with serum ferritin > 300 ng/ml; p = 0.006), and diabetes (44.7% versus 28.0%; p = 0.03). No differences were found in the prevalence of heart disease, arthritis, or liver disease, except for the rate of liver biopsy (10.9% versus 1.8% [p = 0.013] in males; 9.1% versus 2% [p = 0.035] in females). Given the higher rate of HH diagnosis than in prior studies, the high penetrance of iron overload, and the frequency of at-risk genotypes, in addition to other suggested actionable adult-onset genetic conditions, opportunistic screening should be considered for p.[Cys282Tyr];[Cys282Tyr] individuals with existing genomic data.