Gene therapy corrects the neurological deficits of mice with sialidosis.

Patients with sialidosis (mucolipidosis type I) type I typically present with myoclonus, seizures, ataxia, cherry-red spots, and blindness because of mutations in the neuraminidase 1 (NEU1) gene. Currently, there is no treatment for sialidosis. In this study, we developed an adeno-associated virus (AAV)-mediated gene therapy for a Neu1 knockout (Neu1-/-) mouse model of sialidosis. The vector, AAV9-P3-NP, included the human NEU1 promoter, NEU1 cDNA, IRES, and CTSA cDNA. Untreated Neu1-/- mice showed astrogliosis and microglial LAMP1 accumulation in the nervous system, including brain, spinal cord, and dorsal root ganglion, together with impaired motor function. Coexpression of NEU1 and protective protein/cathepsin A (PPCA) in neonatal Neu1-/- mice by intracerebroventricular injection, and less effective by facial vein injection, decreased astrogliosis and LAMP1 accumulation in the nervous system and improved rotarod performance of the treated mice. Facial vein injection also improved the grip strength and survival of Neu1-/- mice. Therefore, cerebrospinal fluid delivery of AAV9-P3-NP, which corrects the neurological deficits of mice with sialidosis, could be a suitable treatment for patients with sialidosis type I. After intracerebroventricular or facial vein injection of AAV vectors, NEU1 and PPCA are expressed together. PPCA-protected NEU1 is then sent to lysosomes, where ß-Gal binds to this complex to form a multienzyme complex in order to execute its function.

Evaluating brain white matter hyperintensity, IQ scores, and plasma neurofilament light chain concentration in early-treated patients with infantile-onset Pompe disease.

PURPOSE: The study aimed to describe central nervous system (CNS) progression in patients with infantile-onset Pompe disease (IOPD) and explore the potential clinical impact and predictors. METHODS: Patients with IOPD treated with enzyme replacement therapy were longitudinally followed with brain magnetic resonance imaging (MRI) and evaluation for IQ scores from 2004 to 2021. Investigation of CNS involvement focused on white matter (WM) abnormalities and was quantified using a scoring system for metachromatic leukodystrophy. MRI scores were correlated with plasma neurofilament light chain (NfL) concentration and IQ scores. RESULTS: A total of 19 patients who started enzyme replacement therapy at a mean age of 26 days were analyzed; the median age at last examination was 12.1 (range = 1.7-19) years. MRI abnormalities were found in all patients, from supratentorial central WM to U-fibers, then to infratentorial WM, and eventually to gray matter. MRI scores progressed (n = 16) at variable rates (range = 0.8-2.7/y) and were positively correlated with age (n = 16) and negatively correlated with IQ scores (n = 8). Plasma NfL concentration was positively correlated with MRI scores (r2 = 0.8569; P < .001; n = 13). CONCLUSION: Our results suggest that the progression of CNS involvement in IOPD may be associated with neuroaxonal injury and decreased IQ scores. NfL could serve as a biomarker for CNS involvement in IOPD.

Streamlined determination of 3-O-methyldopa in dried blood spots: Prospective screening for aromatic l-amino-acid decarboxylase deficiency.

BACKGROUND: Aromatic L-amino-acid decarboxylase (AADC) deficiency diagnosis is often delayed by low disease awareness and specific laboratory examinations. We demonstrated that an elevated concentration of L-dopa metabolite 3-O-methyldopa (3-OMD) in dried blood spots could be integrated into a newborn screening program to detect AADC deficiency. METHODS: DBS samples for amino acid and acylcarnitine analysis using NeoBase™2 reagents were also analyzed for the 3-OMD concentration using 13C6-phenylalanine as an internal standard. For samples exceeding the pre-defined cutoffs, an additional spot was punched from the original filter paper for second-tier 3-OMD measurement by high performance liquid chromatography (HPLC)-MS/MS assay. Newborns with a 3-OMD concentration exceeding 500 ng/mL were referred for confirmatory testing. RESULTS: From Feb. 2020 to Dec. 2022, 157,371 newborns were screened for AADC deficiency. Eight newborns exhibited an elevated 3-OMD concentration (839-5170 ng/mL). Among them, six newborns were confirmed to carry two pathogenic DDC variants, indicating an incidence of AADC deficiency of ∼1:26,000 (95% confidence interval: 1 in 12,021 to 1 in 57,228). During the follow-up period, all six patients developed typical symptoms of AADC deficiency. CONCLUSION: The screening for 3-OMD, a target for AADC deficiency, could be easily integrated into the existing newborn screening programs and facilitate the future application for early diagnosis and effective treatment.

Prevalence of DDC genotypes in patients with aromatic L-amino acid decarboxylase (AADC) deficiency and in silico prediction of structural protein changes.

Aromatic L-amino acid decarboxylase (AADC) deficiency is a rare autosomal recessive genetic disorder affecting the biosynthesis of dopamine, a precursor of both norepinephrine and epinephrine, and serotonin. Diagnosis is based on the analysis of CSF or plasma metabolites, AADC activity in plasma and genetic testing for variants in the DDC gene. The exact prevalence of AADC deficiency, the number of patients, and the variant and genotype prevalence are not known. Here, we present the DDC variant (n = 143) and genotype (n = 151) prevalence of 348 patients with AADC deficiency, 121 of whom were previously not reported. In addition, we report 26 new DDC variants, classify them according to the ACMG/AMP/ACGS recommendations for pathogenicity and score them based on the predicted structural effect. The splice variant c.714+4A>T, with a founder effect in Taiwan and China, was the most common variant (allele frequency = 32.4%), and c.[714+4A>T];[714+4A>T] was the most common genotype (genotype frequency = 21.3%). Approximately 90% of genotypes had variants classified as pathogenic or likely pathogenic, while 7% had one VUS allele and 3% had two VUS alleles. Only one benign variant was reported. Homozygous and compound heterozygous genotypes were interpreted in terms of AADC protein and categorized as: i) devoid of full-length AADC, ii) bearing one type of AADC homodimeric variant or iii) producing an AADC protein population composed of two homodimeric and one heterodimeric variant. Based on structural features, a score was attributed for all homodimers, and a tentative prediction was advanced for the heterodimer. Almost all AADC protein variants were pathogenic or likely pathogenic.

Combining Panel-Based Next-Generation Sequencing and Exome Sequencing for Genetic Liver Diseases.

OBJECTIVES: To determine how advanced genetic analysis methods may help in clinical diagnosis. STUDY DESIGN: We report a combined genetic diagnosis approach for patients with clinical suspicion of genetic liver diseases in a tertiary referral center, using tools either tier 1: Sanger sequencing on SLC2SA13, ATP8B1, ABCB11, ABCB4, and JAG1 genes, tier 2: panel-based next generation sequencing (NGS), or tier 3: whole-exome sequencing (WES) analysis. RESULTS: In a total of 374 patients undergoing genetic analysis, 175 patients received tier 1 Sanger sequencing based on phenotypic suspicion, and pathogenic variants were identified in 38 patients (21.7%). Tier 2 included 216 patients (39 of tier 1-negative patients) who received panel-based NGS, and pathogenic variants were identified in 60 (27.8%). In tier 3, 41 patients received WES analysis, and 20 (48.8%) obtained genetic diagnosis. Pathogenic variants were detected in 6 of 19 (31.6%) who tested negative in tier 2, and a greater detection rate in 14 of 22 (63.6%) patients with deteriorating/multiorgan disease receiving one-step WES (P = .041). The overall disease spectrum is comprised of 35 genetic defects; 90% of genes belong to the functional categories of small molecule metabolism, ciliopathy, bile duct development, and membrane transport. Only 13 (37%) genetic diseases were detected in more than 2 families. A hypothetical approach using a small panel-based NGS can serve as the first tier with diagnostic yield of 27.8% (98/352). CONCLUSIONS: NGS based genetic test using a combined panel-WES approach is efficient for the diagnosis of the highly diverse genetic liver diseases.

Continued benefit of nusinersen initiated in the presymptomatic stage of spinal muscular atrophy: 5-year update of the NURTURE study.

INTRODUCTION/AIMS: NURTURE (NCT02386553) is an open-label study of nusinersen in children (two SMN2 copies, n = 15; three SMN2 copies, n = 10) who initiated treatment in the presymptomatic stage of spinal muscular atrophy (SMA). A prior analysis after ~3 y showed benefits on survival, respiratory outcomes, motor milestone achievement, and a favorable safety profile. An additional 2 y of follow-up (data cut: February 15, 2021) are reported. METHODS: The primary endpoint is time to death or respiratory intervention (≥6 h/day continuously for ≥7 days or tracheostomy). Secondary outcomes include overall survival, motor function, and safety. RESULTS: Median age of children was 4.9 (3.8-5.5) y at last visit. No children have discontinued the study or treatment. All were alive. No additional children utilized respiratory intervention (defined per primary endpoint) since the prior data cut. Children with three SMN2 copies achieved all World Health Organization (WHO) motor milestones, with all but one milestone in one child within normal developmental timeframes. All 15 children with two SMN2 copies achieved sitting without support, 14/15 walking with assistance, and 13/15 walking alone. Mean Hammersmith Functional Motor Scale Expanded total scores showed continued improvement. Subgroups with two SMN2 copies, minimum baseline compound muscle action potential amplitude ≥2 mV, and no baseline areflexia had better motor and nonmotor outcomes versus all children with two SMN2 copies. DISCUSSION: These results demonstrate the value of early treatment, durability of treatment effect, and favorable safety profile after ~5 y of nusinersen treatment. Inclusion/exclusion criteria and baseline characteristics should be considered when interpreting presymptomatic SMA trial data.

Harnessing polyhydroxylated pyrrolidines as a stabilizer of acid alpha-glucosidase (GAA) to enhance the efficacy of enzyme replacement therapy in Pompe disease.

To discover small molecules as acid alpha-glucosidase (GAA) stabilizers for potential benefits of the exogenous enzyme treatment toward Pompe disease cells, we started from the initial screening of the unique chemical space, consisting of sixteen stereoisomers of 2-aminomethyl polyhydroxylated pyrrolidines (ADMDPs) to find out two primary stabilizers 17 and 18. Further external or internal structural modifications of 17 and 18 were performed to increase structural diversity, followed by the protein thermal shift study to evaluate the GAA stabilizing ability. Fortunately, pyrrolidine 21, possessing an l-arabino-typed configuration pattern, was identified as a specific potent rh-GAA stabilizer, enabling the suppression of rh-GAA protein denaturation. In a cell-based Pompe model, co-administration of 21 with rh-GAA protein significantly improved enzymatic activity (up to 5-fold) compared to administration of enzyme alone. Potentially, pyrrolidine 21 enables the direct increase of ERT (enzyme replacement therapy) efficacy in cellulo and in vivo.

A Pilot Study of Biliary Atresia Newborn Screening Using Dried Blood Spot Matrix Metalloproteinase-7.

OBJECTIVES: Timely diagnosis is a critical challenge and is associated with improved survival of biliary atresia (BA) patients. We aimed to measure matrix metalloproteinase-7 (MMP-7) levels in BA patients within 3 days of birth using the dried blood spot (DBS) method and evaluate its potential as a screening tool. METHODS: The study enrolled 132 patients, including 25 patients diagnosed with BA and 107 non-BA patients with other congenital or perinatal conditions from the National Taiwan University Children Hospital. The stored DBS samples collected from 48 to 72 hours of life were retrieved from newborn screening centers. MMP-7 on the DBS was quantified using a sensitive sandwich enzyme-linked immunosorbent assay (ELISA). RESULTS: The MMP-7 levels of BA patients on the DBS were significantly higher than those of non-BA patients (19.2 ± 10.4 vs 5.6 ± 2.7 ng/mL, P value < 0.0001). MMP-7 levels in non-BA patients, including 5 patients with hepatobiliary structural anomaly, 9 patients with intrahepatic cholestasis, and 93 patients with other perinatal diseases, were 11.6 ± 4.2 ng/mL, 6.9 ± 3.0 ng/mL, and 5.2 ± 2.1 ng/mL, respectively. The DBS MMP-7 level showed good accuracy for identifying BA, with an area under the curve of 93.7% [95% confidence interval (CI): 87.7%-99.7%]. The MMP-7 cutoff at 8.0 ng/mL showed a sensitivity of 92.0% (95% CI: 75.0%-98.6%) and specificity of 92.5% (95% CI: 85.9%-96.1%) for detecting BA from other congenital or perinatal diseases. CONCLUSIONS: MMP-7 DBS analysis can be used to distinguish BA from other conditions as early as 3 days of age.

Long-term efficacy and safety of eladocagene exuparvovec in patients with AADC deficiency.

Aromatic L-amino acid decarboxylase deficiency results in decreased neurotransmitter levels and severe motor dysfunction. Twenty-six patients without head control received bilateral intraputaminal infusions of a recombinant adeno-associated virus type 2 vector containing the human aromatic L-amino acid decarboxylase gene (eladocagene exuparvovec) and have completed 1-year evaluations. Rapid improvements in motor and cognitive function occurred within 12 months after gene therapy and were sustained during follow-up for >5 years. An increase in dopamine production was demonstrated by positron emission tomography and neurotransmitter analysis. Patient symptoms (mood, sweating, temperature, and oculogyric crises), patient growth, and patient caretaker quality of life improved. Although improvements were observed in all treated participants, younger age was associated with greater improvement. There were no treatment-associated brain injuries, and most adverse events were related to underlying disease. Post-surgery complications such as cerebrospinal fluid leakage were managed with standard of care. Most patients experienced mild to moderate dyskinesia that resolved in a few months. These observations suggest that eladocagene exuparvovec treatment for aromatic L-amino acid decarboxylase deficiency provides durable and meaningful benefits with a favorable safety profile.

Deciphering the diagnostic dilemma: A comprehensive review of the Taiwanese cardiac variant in Fabry disease.

Molecular diagnosis has undergone rapid and significant advancements in recent years. But because molecular diagnosis can be conducted independently of phenotype, it can engender ambiguity and potential misinterpretations in disease diagnosis. Fabry disease, an X-linked lysosomal storage disorder, arises from a deficiency in α-galactosidase A. In 2002, Ishii and colleagues uncovered a variant (IVS4+919G > A) deep within intron 4 of the GLA gene that could lead to aberrant splicing of the GLA mRNA. This variant is present in 1:875 males in Taiwan, and many patients with hypertrophic cardiomyopathy and the IVS4+919G > A variant are currently treated by enzyme replacement therapy, an expensive treatment. Unfortunately, till now only one article published in 2013 described the outcome of treatment. This review summarized the conflicting evidence about the clinical relevance of the IVS4+919G > A variant, and suggest a multifactorial model, rather than a monogenic model, for the involvement of the IVS4+919G > A variant in hypertrophic cardiomyopathy. The diagnostic dilemma for this Taiwanese cardiac variant in Fabry disease clearly emphasizes the need for precise interpretation and application of molecular diagnostic results.

Improved diagnosis of citrin deficiency by newborn screening using a molecular second-tier test.

BACKGROUND: Citrin deficiency is an autosomal recessive disorder caused by variants of the SLC25A13 gene. Although newborn screening (NBS) provides an opportunity for its early diagnosis and treatment, citrin deficiency detection rates remain lower than those estimated. METHODS: Before 2018, NBS for citrin deficiency was based on citrulline levels alone. In June 2018, a second-tier molecular test was implemented to detect 11 common variants of the SLC25A13 gene and improve the NBS detection rates. This study compares the incidence rates and costs before and after the second-tier implementation. RESULTS: Prior to 2018, five subjects were diagnosed via NBS, and 12 of 555,449 newborns screened were missed. In comparison, 11 subjects were diagnosed out of 198,071 newborns screened after 2018, and there were no false-negatives. The citrin deficiency detection rate increased from 1/32,673 to 1/18,006 after the second-tier test was implemented, with only a minimal increase in the total cost. The number of false-positive in our cohort was tolerable. Subjects with citrin deficiency may present with borderline elevated citrulline levels; these can remain slightly elevated or increase considerably on retest. Four patients (80%) detected prior to second-tier testing and six patients (55%) detected after it was implemented were identified based on the citrulline levels alone. However, at the time of second blood sampling, the normal citrulline level of five subjects did not exclude a citrin deficiency diagnosis. CONCLUSIONS: Our study shows that it is vital and cost-effective to employ second-tier molecular testing to improve the detection of citrin deficiency by NBS.

Outcome of Later-Onset Pompe Disease Identified Through Newborn Screening.

OBJECTIVE: To determine the outcomes of patients with later-onset Pompe disease (LOPD) identified through newborn screening (NBS). STUDY DESIGN: A prospective observational cohort study was conducted from the initiation of Pompe disease NBS by following subjects every 3-12 months for motor development and biochemical markers. RESULTS: Between 2005 and 2018, 39 of 994 975 newborns evaluated were classified as having LOPD based on low acid α-glucosidase (GAA) activity but no cardiac involvement at the time of screening. As of December 2020, 8 of these 39 infants (21%) were treated with enzyme replacement therapy owing to persistent elevation of creatine kinase (CK), cardiac involvement, or developmental delay. All subjects' physical performance and endurance improved after treatment. Subjects carrying c.[752C>T;761C>T] and c.[546+5G>T; 1726G>A] presented a phenotype of nonprogressive hypotonia, muscle weakness, and impairment in physical fitness tests, but they have not received treatment. CONCLUSIONS: One-fifth of subjects identified through NBS as having LOPD developed symptoms after a follow-up of up to 15 years. NBS was found to facilitate the early detection and early treatment of those subjects. GAA variants c.[752C>T;761C>T] and c.[546+5G>T; 1726G>A] might not cause Pompe disease but still may affect skeletal muscle function.

Duchenne muscular dystrophy newborn screening: the first 50,000 newborns screened in Taiwan.

BACKGROUND: Duchenne muscular dystrophy (DMD/Duchenne) is a progressive X-linked muscular disease with an overall incidence of 1:5,000 live male births. Recent availability in treatment for DMD raised the need of early diagnosis, and DMD became as a selective item of newborn screening (NBS) since Feb. 2021 in our center. MATERIALS AND METHODS: Dried blood spots (DBS) muscle-type creatine kinase (CK) isoform was measured with a commercialized kit with age-adjusted cutoffs. Subjects with an elevation of CK in the first screen were requested for a re-screen 2 weeks later. A DBS whole-exome sequencing (WES) panel for dystrophin and other neuromuscular-related genes was applied to confirm the diagnosis for subjects with persistent hyperCKemia. RESULTS: During a 1-year period, 50,572 newborns (male 26,130) received DMD screening at a mean age of 2 days (SD 1 day). Among them, 632 (1.2%) had an elevated CK value. A re-screen at a mean age of 14 days (SD 8 days) revealed 14 subjects with persistent hyperCKemia, and DMD was confirmed in 3 of them. The incidence of DMD in Taiwan was 1:8,710 (95% CI 1 in 2,963 to 1 in 25,610) live birth males. Results of DMD DBS also assisted in Pompe newborn screening. CONCLUSIONS: NBS for DMD enables earlier management of the disease. The high re-screening rate could potentially be waived by moving the DBS WES assay to a second-tier test. The long-term benefit and the impact of newborn screening on the prognosis of DMD, however, remain further elucidated.

Short stature leads to a diagnosis of Jansen-de Vries syndrome in two unrelated Taiwanese girls: A case report and literature review.

Short stature and intellectual disability are two of the major components of many dysmorphic syndromes. Jansen-de Vries syndrome (JDVS) is a rare syndromic disorder that was discovered recently using next-generation sequencing. It is characterized by hypotonia, developmental delay, a dysmorphic face, short stature, and high pain threshold and is caused by the variants of the protein phosphatase magnesium-dependent 1D (PPM1D) gene. Here, we report the first two cases of PPM1D mutations in Taiwan; both had de novo variants in exon 6. Both presented with short stature, developmental delay, and dysmorphic faces. In addition to the characteristics listed above, syndactyly was noted in one. Genetic studies should be considered when approaching a patient with growth retardation, intellectual disability, and other major or minor dysmorphisms.

Clinical and molecular features of idiopathic hypogonadotropic hypogonadism in Taiwan: A single center experience.

BACKGROUND: Idiopathic (isolated) hypogonadotropic hypogonadism (IHH) is a rare disease that can be classified as Kallmann syndrome (KS) or normosmic IHH (nIHH). This study investigated the phenotype and genotype of IHH in Taiwanese patients. METHODS: Twenty-six unrelated IHH patients were included in this study and their clinical, hormonal, and radiological findings were analyzed retrospectively. Whole exome sequencing (WES) was performed to identify the etiology. RESULTS: The 26 patients (M:F = 19:7) were divided into a KS group (n = 11) and a nIHH group (n = 15). The diagnosis was earlier in boys than in girls. Fifteen patients were found to have pathogenic/likely pathogenic (P/LP) variants of IHH-associated genes, and the mutation detection rate was 58%. CHD7, FGFR1, and ANOS1 were the most common genetic etiologies identified in this group. Two patients with nIHH were found to have de novo SOX11 mutations and Coffin-Siris syndrome features. After treatment, the height outcomes and secondary sexual characteristics were significantly improved. There were no obvious differences between the genetically resolved (GR), variants of uncertain significance (VUS) and genetically unresolved groups (GUR). CONCLUSION: Whole exome sequencing is useful in patients with IHH, and we identified the SOX11 gene as a causal factor in this study. We described the clinical, hormonal, and molecular characteristics, and the treatment outcomes, of Taiwanese patients with IHH, which should aid therapeutic planning and further research.

The diversity of hereditary neuromuscular diseases: Experiences from molecular diagnosis.

BACKGROUND: Hereditary neuromuscular diseases (NMDs) are a group of rare disorders, and the diagnosis of these diseases is a substantial burden for referral centers. Although next-generation sequencing (NGS) has identified a large number of genes associated with hereditary NMDs, the diagnostic rates still vary across centers. METHODS: Patients with a suspected hereditary NMD were referred to neuromuscular specialists at the National Taiwan University Hospital. Molecular diagnoses were performed by employing a capture panel containing 194 genes associated with NMDs. RESULTS: Among the 50 patients referred, 43 had a suspicion of myopathy, and seven had polyneuropathy. The overall diagnostic rate was 58%. Pathogenic variants in 19 genes were observed; the most frequent pathogenic variant found in this cohort (DYSF) was observed in only four patients, and 10 pathogenic variants were observed in one patient each. One case of motor neuron disease was clinically mistaken for myopathy. A positive family history increased the diagnostic rate (positive: 72.7% vs. negative: 56.3%). Fourteen patients with elevated plasma creatine kinase levels remained without a diagnosis. CONCLUSION: The application of NGS in this single-center study proves the great diversity of hereditary NMDs. A capture panel is essential, but high-quality clinical and laboratory evaluations of patients are also indispensable.

CMAP changes upon symptom onset and during treatment in spinal muscular atrophy patients: lessons learned from newborn screening.

PURPOSE: Early identification and treatment of spinal muscular atrophy (SMA) are crucial but difficult. In this study, we aimed to assess the significance of compound motor action potential (CMAP) amplitude in patients identified through a newborn screening program. METHODS: We initiated a large-scale population newborn screening program for SMA in Taiwan in 2014. Patients had access to treatment through clinical trials or expanded use programs. Symptomatic patients were evaluated regularly, including CMAP exams. RESULTS: Among 364,000 screened newborns, 21 were diagnosed with SMA. The incidence of SMA was around 1 in 17,000 live births, and 70% developed SMA type 1. All infants with two SMN2 copies became symptomatic before the age of 1 month. CMAP amplitudes of 12 newborns were available, including 6 who were subsequently treated with nusinersen. We found that a rapid decrease of CMAP amplitude was an early predictor of symptom onset. Pretreatment CMAP and rapid increment of post-treatment CMAP could predict better treatment outcomes. CONCLUSION: This study prospectively demonstrated the incidence of SMA and its types. Our results imply the importance of pretreatment CMAP amplitude and rapid reversal of post-treatment CMAP amplitude with regard to disease presentation and also treatment outcomes.

Throwing a spotlight on under-recognized manifestations of Gaucher disease: Pulmonary involvement, lymphadenopathy and Gaucheroma.

BACKGROUND: Gaucher disease (GD) is a rare lysosomal storage disorder classically subdivided into type 1 (non-neuronopathic) GD, and types 2 and 3 (neuronopathic) GD. It is typically characterized by clinical manifestations including anemia, thrombocytopenia, hepatosplenomegaly, bone lesions, and (in more severe forms) neurological impairment. However, less-commonly reported and often under-recognized manifestations exist, which potentially have a significant impact on patient outcomes. Greater efforts are needed to understand, recognize, and manage these manifestations. OBJECTIVES: This review provides a synthesis of published information about three under-recognized GD manifestations (pulmonary involvement, lymphadenopathy, and Gaucheroma) and recommends diagnostic, management, and treatment strategies based on the available literature and author experience. The authors aim to raise awareness about these serious, progressive, and sometimes life-threatening conditions, which are often diagnosed late in life. CONCLUSIONS: Little is known about the incidence, pathophysiology, prognostic factors, and optimal management of pulmonary involvement, lymphadenopathy, and Gaucheroma in patients with GD. Enzyme replacement therapy (ERT) has shown limited efficacy for the prevention and treatment of these manifestations. More research is needed to evaluate the potential effect of substrate reduction therapy (SRT) with glucosylceramide synthase (GCS) inhibitors, and to develop additional approaches to treat these GD manifestations. Improvements in data collection registries and international data-sharing are required to better understand the impact of these manifestations on GD patients, help develop effective management strategies, and, ultimately, improve patient outcomes.

Diversity in heritable disorders of connective tissue at a single center.

BACKGROUND: Heritable disorders of connective tissue (HDCT) is a heterogeneous group of conditions caused by defects in genes responsible for extracellular matrix elements. Although next-generation sequencing (NGS) technology can be used to analyze many genes at a time, precisely diagnosing HDCT is still challenging because of the overlapping phenotypes and genotypes. METHODS: A 67-gene NGS targeted panel or whole-exome sequencing was employed for the diagnosis of HDCT over 4 years. Phenotypes and genotypes of patients were analyzed retrospectively. RESULTS: Mutations in 16 genes were discovered in 34 patients with the suspicion of Ehlers-Danlos syndrome (n = 7), Marfan syndrome (n = 2), osteogenesis imperfecta (n = 3), skeletal dysplasia (n = 18), and others (n = 4). Eighteen patients were found to have mutations in collagen genes, three had SERPINF1 mutations, two had TRPV4 mutations, two had FBN1 mutations, two had COMP mutations, and mutations in seven other genes were found in one patient each. The eight patients with COL1A1 mutations had a wide variation in phenotype. Patients with COL3A1 and COL5A1 mutations presented with classic EDS, those with SERPINF1 mutations presented with typical OI type VI, those with TRPV4 mutations presented with severe spinal deformity, and those with COL2A1 mutations presented with syndromic or nonsyndromic bone dysplasia or only short stature. CONCLUSION: A wide diversity in HDCT was observed. Therefore, knowledge about the phenotype-genotype correlation in HDCT is still crucial in the diagnosis of this group of diseases, and an improvement in the screening tool will be needed.

Biparental Inheritance of Mitochondrial DNA in Humans.

Although there has been considerable debate about whether paternal mitochondrial DNA (mtDNA) transmission may coexist with maternal transmission of mtDNA, it is generally believed that mitochondria and mtDNA are exclusively maternally inherited in humans. Here, we identified three unrelated multigeneration families with a high level of mtDNA heteroplasmy (ranging from 24 to 76%) in a total of 17 individuals. Heteroplasmy of mtDNA was independently examined by high-depth whole mtDNA sequencing analysis in our research laboratory and in two Clinical Laboratory Improvement Amendments and College of American Pathologists-accredited laboratories using multiple approaches. A comprehensive exploration of mtDNA segregation in these families shows biparental mtDNA transmission with an autosomal dominantlike inheritance mode. Our results suggest that, although the central dogma of maternal inheritance of mtDNA remains valid, there are some exceptional cases where paternal mtDNA could be passed to the offspring. Elucidating the molecular mechanism for this unusual mode of inheritance will provide new insights into how mtDNA is passed on from parent to offspring and may even lead to the development of new avenues for the therapeutic treatment for pathogenic mtDNA transmission.