Skeletal Muscle Magnetic Resonance Imaging of the Lower Limbs in Late-onset Lipid Storage Myopathy with Electron Transfer Flavoprotein Dehydrogenase Gene Mutations

Features and diagnostic value of body composition in patients with late-onset multiple acyl-CoA dehydrogenase deficiency

OBJECTIVE

This study aims to analyse the body composition features and its changes after treatment in patients with late-onset multiple acyl-CoA dehydrogenase deficiency (MADD).

METHODS

Body composition was measured in patients with late-onset MADD, inflammatory myopathies, mitochondrial myopathy, and healthy controls. The correlation analyses between body composition and traditional parameters were performed. Comparisons between groups and receiver operating characteristic curve analyses were performed.

RESULTS

A total of 42 participants included 13 patients with late-onset MADD, 13 healthy controls, 10 with inflammatory myopathy, and 6 with mitochondrial myopathy. Bilateral grip strength and forced vital capacity (FVC) were moderate-strong correlated with skeletal muscle mass (right hand grip strength: r = 0.728, P < 0.001; left hand grip strength: r = 0.676, P < 0.001; FVC: r = 0.754, P < 0.001). Serum CK was moderately and negatively correlated with right hand grip strength (r = - 0.618, P = 0.005), left hand grip strength (r = - 0.630, P = 0.004), FVC (r = - 0.665, P = 0.002), manual muscle testing (MMT) (r = - 0.729, P = 0.000), and lean body mass skeletal muscle percentage (r = - 0.501, P = 0.029). Body composition features in patients with late-onset MADD were as follows: (1) obvious fat accumulation, (2) reduction of muscle mass, and (3) reduction of body water and intracellular water ratio. Some indicators of body composition were found to be valuable in diagnosis and eliminating differential diagnoses, such as visceral fat area (sensitivity 84.62%; specificity 92.31%; AUC 0.905) and fat mass (sensitivity 84.62%; specificity 75.00%; AUC 0.837). Seven patients were followed-up (2-9 months). Prior to treatment, the changes in body composition in these patients were conflicting.

CONCLUSIONS

Hand grip strength and FVC were strongly associated with body composition. Body composition features in late-onset MADD are fat accumulation, muscle loss, decrease in total body water, and intracellular water ratio. Body composition features are valuable for diagnosis and assessment.

ETF dehydrogenase advances in molecular genetics and impact on treatment

Electron transfer flavoprotein dehydrogenase, also called ETF-ubiquinone oxidoreductase (ETF-QO), is a protein localized in the inner membrane of mitochondria, playing a central role in the electron-transfer system. Indeed, ETF-QO mediates electron transport from flavoprotein dehydrogenases to the ubiquinone pool. ETF-QO mutations are often associated with riboflavin-responsive multiple acyl-CoA dehydrogenase deficiency (RR-MADD, OMIM#231680), a multisystem genetic disease characterized by various clinical manifestations with different degrees of severity. In this review, we outline the clinical features correlated with ETF-QO deficiency and the benefits obtained from different treatments, such as riboflavin, L-carnitine and/or coenzyme Q10 supplementation, and a diet poor in fat and protein. Moreover, we provide a detailed summary of molecular and bioinformatic investigations, describing the mutations identified in ETFDH gene and highlighting their predicted impact on enzymatic structure and activity. In addition, we report biochemical and functional analysis, performed in HEK293 cells and patient fibroblasts and muscle cells, to show the relationship between the nature of ETFDH mutations, the variable impairment of enzyme function, and the different degrees of RR-MADD severity. Finally, we describe in detail 5 RR-MADD patients carrying different ETFDH mutations and presenting variable degrees of clinical symptom severity.

A systematic review of late-onset and very-late-onset multiple acyl-coenzyme A dehydrogenase deficiency: Cohort analysis and patient report from Taiwan

Multiple acyl-coenzyme A dehydrogenase deficiency (MADD) is a rare metabolic disorder with a dramatic clinical presentation. It was recently discovered that MADD may present at an advanced age. The clinical and laboratory data of an index patient and patients previously diagnosed at our institution were collected. A systematic review of previous studies retrieved from the PubMed, MEDLINE, and Embase databases published by February 1, 2020 was performed to collect patients with very-late-onset MADD (VLO-MADD, onset age > 60 years) globally and patients with late-onset MADD (LO-MADD, onset age < 60 years) in Taiwan. The clinical characteristics of the VLO-MADD patients were compared to those of LO-MADD patients. We report a patient with VLO-MADD who developed the first symptom at the age of 61 years. The patient presented with a Reye-like syndrome after taking aspirin for coronary artery disease. Repeated bouts of weakness were noted. Two variants of c.250 G > A (;) 419C > T were observed in the ETFDH gene. Another four patients with VLO-MADD were identified globally. Eighteen patients with LO-MADD were collected from our department and previously reported patients in Taiwan. There was no difference in the clinical symptoms (except for the onset age) or laboratory data between these two groups. Homozygous variants were not observed in any patients in the VLO-MADD group but were detected in 12 patients (66.6%) in the LO-MADD group (p = 0.014). Patients with MADD may first show symptoms in their 6th decade or beyond. The disease course may lead to erroneous diagnoses in this age group.

Skin damage in a patient with lipid storage myopathy with a novel ETFDH mutation responsive to riboflavin

Background: Recessive mutations in ETFDH gene have been associated with Multiple Acyl-CoA dehydrogenase deficiency (MADD). The late-onset MADD is often muscle involved, presenting with lipid storage myopathy (LSM). The symptoms of LSM were heterogeneous and definite diagnosis of this disease depends on the pathology and gene test.Methods: Neurological examination, muscle biopsy, and MRI examinations were performed in a patient with a novel missense ETFDH mutation.Results: We describe a patient with lipid storage myopathy complicated with skin damage. In addition, the next generation revealed a novel missense mutation (c.970G > T, p.Val324Leu) in exon 8, which was predicted to be a disease-causing mutation by Mutation-taster, and destroy the function of the protein by Sift.Conclusion: These findings expand the known mutational spectrum of ETFDH and phenotype of MADD.

Two novel ETFDH mutations in a patient with lipid storage myopathy

Supplemental Digital Content is available in the text

Rhabdomyolysis and respiratory insufficiency due to the common ETFDH mutation of c.250G>A in two patients with late-onset multiple acyl-CoA dehydrogenase deficiency

Supplemental Digital Content is available in the text

Clinical and muscle magnetic resonance image findings in patients with late-onset multiple acyl-CoA dehydrogenase deficiency

Background:

Late-onset multiple acyl-coA dehydrogenase deficiency (MADD) is an autosomal recessive inherited metabolic disorder. It is still unclear about the muscle magnetic resonance image (MRI) pattern of the distal lower limb pre- and post-treatment in patients with late-onset MADD. This study described the clinical and genetic findings in a cohort of patients with late-onset MADD, and aimed to characterize the MRI pattern of the lower limbs.

Methods:

Clinical data were retrospectively collected from clinic centers of Peking University People's Hospital between February 2014 and February 2018. Muscle biopsy, blood acylcarnitines, and urine organic acids profiles, and genetic analysis were conducted to establish the diagnosis of MADD in 25 patients. Muscle MRI of the thigh and leg were performed in all patients before treatment. Eight patients received MRI re-examinations after treatment.

Results:

All patients presented with muscle weakness or exercise intolerance associated with variants in the electron transfer flavoprotein dehydrogenase gene. Muscle MRI showed a sign of both edema-like change and fat infiltration selectively involving in the soleus (SO) but sparing of the gastrocnemius (GA) in the leg. Similar sign of selective involvement of the biceps femoris longus (BFL) but sparing of the semitendinosus (ST) was observed in the thigh. The sensitivity and specificity of the combination of either “SO+/GA–” sign or “BFL+/ST–” sign for the diagnosis of late-onset MADD were 80.0% and 83.5%, respectively. Logistic regression model supported the findings. The edema-like change in the SO and BFL muscles were quickly recovered at 1 month after treatment, and the clinical symptom was also relieved.

Conclusions:

This study expands the clinical and genetic spectrums of late-onset MADD. Muscle MRI shows a distinct pattern in the lower limb of patients with late-onset MADD. The dynamic change of edema-like change in the affected muscles might be a potential biomarker of treatment response.

Muscle Magnetic Resonance Imaging for the Differentiation of Multiple Acyl-CoA Dehydrogenase Deficiency and Immune-mediated Necrotizing Myopathy

Background:

Clinically, it is difficult to differentiate multiple acyl-CoA dehydrogenase deficiency (MADD) from immune-mediated necrotizing myopathy (IMNM) because they display similar symptoms. This study aimed to determine whether muscle magnetic resonance imaging (MRI) could be used for differential diagnosis between MADD and IMNM.

Methods:

The study evaluated 25 MADD patients, confirmed by muscle biopsy and ETFDH gene testing, and 30 IMNM patients, confirmed by muscle biopsy. Muscles were assessed for edema and fatty replacement using thigh MRI (tMRI). Degrees and distribution patterns of fatty infiltration and edema in gluteus maximus and thigh muscles were compared.

Results:

Total fatty infiltration and edema scores (median, [Q1, Q3]) were 4.00 (1.00, 15.00) and 0 (0, 4.00) in MADD and 14.50 (8.00, 20.75) and 22.00 (16.75, 32.00) in IMNM, respectively, which were significantly more severe in IMNM than that in MADD (P = 0.000 and P = 0.004, respectively). Edema scores for gluteus maximus, long head of biceps femoris, and semimembranosus were significantly higher in IMNM than in MADD (all P = 0.000). Fatty infiltration scores for anterior and medial compartments were significantly more severe in IMNM than that in MADD (all P = 0.000).

Conclusion:

Different patterns of muscle involvement on tMRI can contribute to differential diagnosis between MADD and IMNM when clinical suspicions alone are insufficient, thereby reducing the need for muscle biopsy.

Muscle MRI in neutral lipid storage disease (NLSD)

Neutral lipid storage disease (NLSD) is a rare inherited disorder of lipid metabolism resulting in lipid droplets accumulation in different tissues. Skeletal muscle could be affected in both two different form of disease: NLSD with myopathy (NLSD-M) and NLSD with ichthyosis (NLSD-I). We present the muscle imaging data of 12 patients from the Italian Network for NLSD: ten patients presenting NLSD-M and two patients with NLSD-I. In NLSD-M gluteus minimus, semimembranosus, soleus and gastrocnemius medialis in the lower limbs and infraspinatus in the upper limbs were the most affected muscles. Gracilis, sartorius, subscapularis, pectoralis, triceps brachii and sternocleidomastoid were spared. Muscle involvement was not homogenous and characteristic “patchy” replacement was observed in at least one muscle in all the patients. Half of the patients showed one or more STIR positive muscles. In both NLSD-I cases muscle involvement was not observed by T1-TSE sequences, but one of them showed positive STIR images in more than one muscle in the leg. Our data provides evidence that muscle imaging can identify characteristic alterations in NLSD-M, characterized by a specific pattern of muscle involvement with “patchy” areas of fatty replacement. Larger cohorts are needed to assess if a distinct pattern of muscle involvement exists also for NLSD-I.