Generation of a human induced pluripotent stem cell line from a patient with GM3 synthase deficiency using self-replicating RNA vector.

GM3 synthase deficiency (GM3SD) is caused by biallelic variants in the ST3GAL5 gene. Early clinical features of GM3SD include infantile onset of severe irritability and feeding difficulties, early intractable seizures, growth failure, hypotonia, sensorineural hearing impairment. We describe the generation and characterization the human induced pluripotent stem cell (hiPSC) line derived from fibroblasts of a 13-year-old girl with GM3 synthase deficiency resulted compound heterozygous for two new variants in the ST3GAL5 gene, c.1166A > G (p.His389Arg) and the c.1024G > A (p.Gly342Ser). The generated hiPSC line shows a normal karyotype, expresses pluripotency markers, and is able to differentiate into the three germ layers.

THC and THC-COOH hair concentrations: Influence of age, gender, consumption habits, cosmetics treatment, and hair features.

Evaluation of Cannabis consumption is required for many purposes (i.e., workplace drug testing and driving license renewal). Hair analysis represents the most adopted and reliable approach for the investigation of repeated or chronic exposure to Cannabis. The main markers are the Δ9-tetrahydrocannabinol (THC) and its main metabolite, 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THC-COOH), as stated by the Society of Hair Testing (SoHT) and the European Workplace Drug Testing Society (EWDTS). In this paper we presented an observational study on the hair concentrations of THC and THC-COOH and influences due to age, gender, consumption habits, and hair features. Data were collected from analysis of scalp hair samples (3-cm proximal segment) provided by subjects tested for THC consumption for personal purposes (i.e., workplace drug testing, personal use proving). The subjects provided an informed consent and a short questionnaire. A new analytical method was previously developed and then adopted. It consisted in a hydrolysis (1 mL of 1 M NaOH at 65 °C, 20 min) and a liquid-liquid extraction (with hexane/ethyl acetate,90/10, v/v in presence of 1.5 mL of H2SO4 1 M) of 25 mg of hair. A liquid chromatograph - tandem mass spectrometer (LC-MS/MS) equipped with a C18 column was used. The acquisition was in multiple reaction monitoring for the following transitions: 315→259, 193 m/z, for THC; 318→196, 123 m/z, for THC-d3; 345→299, 193 m/z for THC-COOH; 348→196, 302 m/z for THC-COOH-d3. Correlation between THC and THC-COOH hair concentrations was analyzed by Spearman's rank correlation coefficient. In order to study the influences of several variables, a new value, Sqrt(THC*THCCOOH), was adopted. Its effectiveness and reliability were proved by the Principal Component Analysis. Relationships between the Sqrt(THC*THCCOOH) and the variables were studied through the Stepwise regression (p = 0.05). The normality of data distribution was tested by the Shapiro-Wilk test. The Lower limits of quantification were 10.0 (THC) and 0.2 (THC-COOH) pg/mg. Accuracy and precision always met the acceptable criteria. Recoveries were > 78% and ion suppression was observed for both the compounds. Data from 126 hair samples were included in this study: 54 subjects(42.9%) were positive both for THC and THC-COOH; none of the samples was positive for a single substance. Concentrations ranged from 0.18 to 1.75 ng/mg (median: 0.78 ng/mg) for THC and from 0.04 to 0.85 ng/mg (median: 0.31 ng/mg) for THC-COOH. Cannabinoids levels seemed to decrease with the age, with lower amounts in the subjects aged > 40 years (p < 0.05). Also years of consumption seemed to have a significant impact on hair concentrations, as higher levels were observed in consumers from > 10 years (p = 0.013). Moreover, this study further provided evidences of a significant reduction of THC and THC-COOH in bleached hair (p = 0.042).

Generation of human induced pluripotent stem cell line (AOUMEYi001-A) from a patient affected by Congenital disorders of glycosylation (ALG8-CDG) using self-replicating RNA vector.

Congenital Disorders of Glycosylation (CDG) are rare inherited metabolic diseases caused by genetic defects in the glycosylation of proteins and lipids. In this study, we describe the generation and characterization of one human induced pluripotent stem cell (hiPSC) line from a 15-year-old male patient with CDG. The patient carried three variants, one (c.122G > A; p.Arg41Gln) inherited from his father and two (c.445 T > G; p.Leu149Arg and the novel c.980C > G; p.Thr327Arg) inherited from his mother in the ALG8 gene (OMIM #608103). The generated hiPSC line shows a normal karyotype, expresses pluripotency markers, and is able to differentiate into the three germ layers.

A Schematic Approach to Defining the Prevalence of COL VI Variants in Five Years of Next-Generation Sequencing.

OBJECTIVE: To define the prevalence of variants in collagen VI genes through a next-generation sequencing (NGS) approach in undiagnosed patients with suspected neuromuscular disease and to propose a diagnostic flowchart to assess the real pathogenicity of those variants. METHODS: In the past five years, we have collected clinical and molecular information on 512 patients with neuromuscular symptoms referred to our center. To pinpoint variants in COLVI genes and corroborate their real pathogenicity, we sketched a multistep flowchart, taking into consideration the bioinformatic weight of the gene variants, their correlation with clinical manifestations and possible effects on protein stability and expression. RESULTS: In Step I, we identified variants in COLVI-related genes in 48 patients, of which three were homozygous variants (Group 1). Then, we sorted variants according to their CADD score, clinical data and complementary studies (such as muscle and skin biopsy, study of expression of COLVI on fibroblast or muscle and muscle magnetic resonance). We finally assessed how potentially pathogenic variants (two biallelic and 12 monoallelic) destabilize COL6A1-A2-A3 subunits. Overall, 15 out of 512 patients were prioritized according to this pipeline. In seven of them, we confirmed reduced or absent immunocytochemical expression of collagen VI in cultured skin fibroblasts or in muscle tissue. CONCLUSIONS: In a real-world diagnostic scenario applied to heterogeneous neuromuscular conditions, a multistep integration of clinical and molecular data allowed the identification of about 3% of those patients harboring pathogenetic collagen VI variants.

The Diagnostic Approach to Mitochondrial Disorders in Children in the Era of Next-Generation Sequencing: A 4-Year Cohort Study.

Mitochondrial diseases (MDs) are a large group of genetically determined multisystem disorders, characterized by extreme phenotypic heterogeneity, attributable in part to the dual genomic control (nuclear and mitochondrial DNA) of the mitochondrial proteome. Advances in next-generation sequencing technologies over the past two decades have presented clinicians with a challenge: to select the candidate disease-causing variants among the huge number of data provided. Unfortunately, the clinical tools available to support genetic interpretations still lack specificity and sensitivity. For this reason, the diagnosis of MDs continues to be difficult, with the new "genotype first" approach still failing to diagnose a large group of patients. With the aim of investigating possible relationships between clinical and/or biochemical phenotypes and definitive molecular diagnoses, we performed a retrospective multicenter study of 111 pediatric patients with clinical suspicion of MD. In this cohort, the strongest predictor of a molecular (in particular an mtDNA-related) diagnosis of MD was neuroimaging evidence of basal ganglia (BG) involvement. Regression analysis confirmed that normal BG imaging predicted negative genetic studies for MD. Psychomotor regression was confirmed as an independent predictor of a definitive diagnosis of MD. The findings of this study corroborate previous data supporting a role for neuroimaging in the diagnostic approach to MDs and reinforce the idea that mtDNA sequencing should be considered for first-line testing, at least in specific groups of children.

Determination of endogenous GHB levels in chest and pubic hair.

Endogenous nature of GHB represents a critical issue for forensic toxicologists, especially in alleged sexual assaults. Therefore, discrimination between physiologically and additional amounts from exogenous sources of such a substance must be effective and reliable in order to avoid severe misinterpretation. This study aimed to quantify the GHB baseline concentrations in chest and pubic hairs collected from 105 healthy volunteers, non-consumers of any drugs of abuse. The final scope was to investigate if these keratin matrices could represent valid alternative to scalp hair when not available. Moreover, we also evaluated the age and gender influences on the GHB baseline levels. 25 mg of hair were incubated overnight with NaOH at 56 °C. After acidification with H2SO4, the solution was liquid-liquid extracted with ethyl acetate and a trimethylsilyl derivatization was then achieved. Analysis was performed in gas chromatography-mass spectrometry in single ion monitoring mode (m/z 233, 234, 147 for GHB; m/z 239, 240 and 147 for GHB-d6). The endogenous amount in "blank" hair was estimated by the standard addition method (0.301 for chest hair and 0.235 ng/mg for pubic hair). GHB concentration ranged from 0.205 to 1.511 ng/mg for chest hair and from 0.310 to 1.913 ng/mg for pubic hair. These values were consistent with previous studies on scalp hair and on pubic hair. Unfortunately, research on chest hair is not available in literature. T-Test and Linear Regression highlighted no statistically significant differences for the two matrices and for all age/gender sub-groups. However, further studies are required to estimate a reliable cut-off value for these keratin matrices. For the first time, we demonstrated the suitability of chest and pubic hair to detect endogenous levels of GHB.

Bi-allelic variants in MTMR5/SBF1 cause Charcot-Marie-Tooth type 4B3 featuring mitochondrial dysfunction.

BACKGROUND: Charcot-Marie-Tooth disease (CMT) type 4B3 (CMT4B3) is a rare form of genetic neuropathy associated with variants in the MTMR5/SBF1 gene. MTMR5/SBF1 is a pseudophosphatase predicted to regulate endo-lysosomal trafficking in tandem with other MTMRs. Although almost ubiquitously expressed, pathogenic variants primarily impact on the peripheral nervous system, corroborating the involvement of MTMR5/SBF1 and its molecular partners in Schwann cells-mediated myelinization. CASE PRESENTATION: We report a case of severe CMT4B3 characterized by early-onset motor and axonal polyneuropathy in an Italian child in absence of any evidence of brain and spine MRI abnormalities or intellectual disability and with a biochemical profile suggestive of mitochondrial disease. Using an integrated approach combining both NGS gene panels and WES analysis, we identified two novel compound heterozygous missense variants in MTMR5/SBF1 gene, p.R763H (c.2291G > A) and p.G1064E (c.3194G > A). Studies in muscle identified partial defects of oxidative metabolism. CONCLUSION: We describe the first case of an early onset severe polyneuropathy with motor and axonal involvement, due to recessive variants in the MTMR5/SBF1 gene, with no evidence of brain and spine MRI abnormalities, intellectual disability, no clinical and neurophysiological evidences of distal sensory impairment, and rapid neuromuscular deterioration. This report suggests that MTMR5/SBF1 should be considered in cases of infantile-onset CMT with secondary mitochondrial dysfunction.

Leopard-like retinopathy and severe early-onset portal hypertension expand the phenotype of KARS1-related syndrome: a case report.

BACKGROUND: Mutations in lysyl-tRNA synthetase (KARS1), an enzyme that charges tRNA with the amino acid lysine in both the cytoplasm and mitochondria, have been associated thus far with autosomal recessive Charcot-Marie-Tooth type CMTRIB, hearing loss type DFNB89, and mitochondrial encephalohepatopathy (MEH) featuring neurodevelopmental disorders with microcephaly, white matter changes, and cardiac and hepatic failure in less than 30 patients. CASE PRESENTATION: We report the clinical, biochemical and molecular findings of a 14-month-old girl with severe MEH compatible clinical features, profound sensorineural hearing loss, leopard spot retinopathy, pancytopenia, and advanced liver disease with portal hypertension leading to death at the age of 30 months. CONCLUSIONS: Whole exome sequencing identified two rare variants in KARS1 gene. Our report expands the allelic and clinical features of tRNA synthase disorders. Moreover, with our report we confirm the usefulness of WES as first tier diagnostic method in infants with complex multisystem phenotypes.

Atypical Ocular Coloboma in Tuberous Sclerosis-2: Report of Two Novel Cases.

ABSTRACT: Tuberous sclerosis complex (TSC) is an autosomal dominant multisystemic disorder caused by mutations in either TSC1 or TSC2 genes and is characterized by hamartomas in multiple organs. The most frequent and best-known ocular manifestation in TSC is the retinal hamartoma. Less frequent ocular manifestations include punched out areas of retinal depigmentation, eyelid angiofibromas, uveal colobomas, papilledema, and sector iris depigmentation. In this article, we report 2 patients carrying known pathogenic variants in the TSC2 gene who exhibited an atypical, unilateral, iris coloboma associated with localized areas of retinal dysembryogenesis.

Patterns and predictors of language representation and the influence of epilepsy surgery on language reorganization in children and young adults with focal lesional epilepsy.

Mapping brain functions is crucial for neurosurgical planning in patients with drug-resistant seizures. However, presurgical language mapping using either functional or structural networks can be challenging, especially in children. In fact, most of the evidence on this topic derives from cross-sectional or retrospective studies in adults submitted to anterior temporal lobectomy. In this prospective study, we used fMRI and DTI to explore patterns of language representation, their predictors and impact on cognitive performances in 29 children and young adults (mean age at surgery: 14.6 ± 4.5 years) with focal lesional epilepsy. In 20 of them, we also assessed the influence of epilepsy surgery on language lateralization. All patients were consecutively enrolled at a single epilepsy surgery center between 2009 and 2015 and assessed with preoperative structural and functional 3T brain MRI during three language tasks: Word Generation (WG), Rhyme Generation (RG) and a comprehension task. We also acquired DTI data on arcuate fasciculus in 24 patients. We first assessed patterns of language representation (relationship of activations with the epileptogenic lesion and Laterality Index (LI)) and then hypothesized a causal model to test whether selected clinical variables would influence the patterns of language representation and the ensuing impact of the latter on cognitive performances. Twenty out of 29 patients also underwent postoperative language fMRI. We analyzed possible changes of fMRI and DTI LIs and their clinical predictors. Preoperatively, we found atypical language lateralization in four patients during WG task, in one patient during RG task and in seven patients during the comprehension task. Diffuse interictal EEG abnormalities predicted a more atypical language representation on fMRI (p = 0.012), which in turn correlated with lower attention (p = 0.036) and IQ/GDQ scores (p = 0.014). Postoperative language reorganization implied shifting towards atypical language representation. Abnormal postoperative EEG (p = 0.003) and surgical failures (p = 0.015) were associated with more atypical language lateralization, in turn correlating with worsened fluency. Neither preoperative asymmetry nor postoperative DTI LI changes in the arcuate fasciculus were observed. Focal lesional epilepsy associated with diffuse EEG abnormalities may favor atypical language lateralization and worse cognitive performances, which are potentially reversible after successful surgery.

A novel LC-MS/MS analytical method for detection of articaine and mepivacaine in blood and its application to a preliminary pharmacokinetic study.

Local anaesthetics (LAs) are commonly used in surgery, especially in dentistry. They cause a transitory inhibition of nerve signal due to the blockade of the voltage-gated sodium channels. LAs are administrated alone or with vasoconstriction agents, such as adrenaline. Toxicity of LAs is associated to neurological and cardiovascular alterations. Tachycardia, arrhythmia, tremors, tonic-clonic seizure and respiratory depression (at high doses) are the main symptoms of intoxication by LAs. Lidocaine, articaine and mepivacaine are among the most used anaesthetics. This study aimed to fully validated a new method for the simultaneous detection of articaine and mepivacaine in whole blood. Sample treatment consisted in a liquid-liquid extraction with phosphate buffer (pH 8, 0.1 M) and ethyl-acetate. Analysis was performed by liquid chromatography-tandem mass spectrometry in multiple reaction monitoring mode (transitions: articaine, 285→8658 m/z; mepivacaine, 247→9870 m/z; lidocaine - internal standard -, 235→8658 m/z). The method proved to be highly sensitive with limit of quantifications for articaine and mepivacaine of 0.8 and 0.1 ng/mL, respectively. Accuracy and precision were always within the acceptance criteria. The new procedure was also successfully applied to a preliminary pharmacokinetics study.

Treatment of haemorrhoidal disease with micronized purified flavonoid fraction and sucralfate ointment.

Hemorrhoidal disease is a very common disease characterized by the presence of a mucous prolapse of the rectum and by varicosis of the hemorrhoidal plexus. Medical therapy is mainly indicated for the treatment of symptoms such as bleeding, pain and itching. The use of the micronized purified flavonoid fraction (MPFF) has proven to be effective in treating symptoms of hemorrhoidal disease. Topical use of sucralfate has shown good results in the reduction of hemorrhoidal pain and itching. Our experience with three cases treated with combined use of MPFF and a topical medical device in the form of rectal ointment, composed by sucralfate and herbal (calendula, witch hazel leaf (hamamelis), chamomile) extracts, has shown good results in terms of pain and itching control and in edema reduction.

Ethyl Glucuronide Concentration in Hair of Detainees: A Preliminary Study.

Through the measurement of ethyl glucuronide in hair (hETG), it is possible to assess chronic alcohol abuse over time. In this paper, we present a study on hETG in Italian prison inmates. Analyses were performed by LC-MS according to a previously published method. Results were evaluated using the cut-offs established by the Society of Hair Testing. Positives samples (ETG > 30 pg/mg) accounted for 6% of all subjects, with concentrations ranging from 42 pg/mg up to 270 pg/mg, abstinent subjects (ETG < 7 pg/mg) accounted for 88%, and moderate alcohol consumption (7 < ETG < 30 pg/mg) for 6% of the subjects. No females displayed ETG values above 30 pg/mg. Among positive samples, only two subjects did not declare heavy alcohol consumption and were found strongly positive at 210 and 270 pg/mg. To the best of our knowledge, this represents the first study on ETG hair concentration on prison inmates.

Neurosurgical treatment of subependymal giant cell astrocytomas in tuberous sclerosis complex: a series of 44 surgical procedures in 31 patients.

BACKGROUND: Subependymal giant cell astrocytomas (SEGA) are benign tumors characteristic of tuberous sclerosis complex (TSC) that may cause hydrocephalus. Various treatments are nowadays available as mTOR inhibitors or surgery. Surgery is still a valid option especially for symptomatic and larger tumors. METHODS: From January 1994 to December 2015, 31 TSC patients harboring SEGA underwent surgery at the Department of Neurosurgery of the Meyer Pediatric Hospital, Florence. Indications for surgery were tumor size and location, growth and cystization/hemorrhage, and hydrocephalus. Clinical data, preoperative and postoperative MRI, recurrence rate, further surgical procedures, and related complications were analyzed. RESULTS: A total of 44 surgeries were performed in 31 TSC patients affected by SEGA, achieving gross total removal (GTR) and subtotal removal (STR), respectively, in 36 and 8 patients. Recurrences occurred in 11 patients; 9 of them underwent further surgical procedures and 2 were treated with mTOR pathway inhibitors. Surgical morbidity and mortality were, respectively, 22.7% and 2.3%. After a mean follow-up of 4.9 years, 90% of patients were tumor-free with good neurological status in 93.3%; twelve (40%) had a ventriculo-peritoneal shunt (VPS) for hydrocephalus. CONCLUSIONS: The present series confirms that the surgical approach, combined with mTOR inhibitors, is still a valid option for the treatment of SEGAs.

Psychotropic substance abuse and fitness to hold a driving license in Italy.

Objective: Driving under the influence (DUI) of psychotropic substances is a serious and widespread problem in road safety. All countries try to reduce the impact with legislative controls over the criteria to regain a driver's license after suspension. In many European countries there are mandatory clinical and toxicological examinations required before a license is regranted. In Italy, individuals convicted of driving under the influence of drugs and/or alcohol must undergo a mandatory medico-legal and forensic toxicological examination prior to regranting of a license. This article reports on the prevalence, trends, and implications of psychotropic substances detected in more than 5,000 subjects submitted to driving license reissuance in the period 2011-2016. Methods: The study involved taking a clinical history, medical examination, and toxicological analysis of both urine and hair samples. Results: There was no change in the prevalence of psychoactive substances in the period 2011-2016. Cocaine was found most often (60%), followed by cannabinoids (15%) and opiates (9%). Methadone and amphetamine stimulants accounted for less than 5% each. Benzodiazepines were present in 15% of samples throughout the period. Conclusion: Cocaine and cannabinoids were the most used substances in the analyzed population, alone and in combination. Benzodiazepines were the most commonly detected prescription medication, raising questions about prescribed medication and driving risk that are not addressed by current legislation.

Next Generation Molecular Diagnosis of Hereditary Spastic Paraplegias: An Italian Cross-Sectional Study.

Hereditary spastic paraplegia (HSP) refers to a group of genetically heterogeneous neurodegenerative motor neuron disorders characterized by progressive age-dependent loss of corticospinal motor tract function, lower limb spasticity, and weakness. Recent clinical use of next generation sequencing (NGS) methodologies suggests that they facilitate the diagnostic approach to HSP, but the power of NGS as a first-tier diagnostic procedure is unclear. The larger-than-expected genetic heterogeneity-there are over 80 potential disease-associated genes-and frequent overlap with other clinical conditions affecting the motor system make a molecular diagnosis in HSP cumbersome and time consuming. In a single-center, cross-sectional study, spanning 4 years, 239 subjects with a clinical diagnosis of HSP underwent molecular screening of a large set of genes, using two different customized NGS panels. The latest version of our targeted sequencing panel (SpastiSure3.0) comprises 118 genes known to be associated with HSP. Using an in-house validated bioinformatics pipeline and several in silico tools to predict mutation pathogenicity, we obtained a positive diagnostic yield of 29% (70/239), whereas variants of unknown significance (VUS) were found in 86 patients (36%), and 83 cases remained unsolved. This study is among the largest screenings of consecutive HSP index cases enrolled in real-life clinical-diagnostic settings. Its results corroborate NGS as a modern, first-step procedure for molecular diagnosis of HSP. It also disclosed a significant number of new mutations in ultra-rare genes, expanding the clinical spectrum, and genetic landscape of HSP, at least in Italy.

The application of artificial intelligence to understand the pathophysiological basis of psychogenic nonepileptic seizures.

Psychogenic nonepileptic seizures (PNES) are episodes of paroxysmal impairment associated with a range of motor, sensory, and mental manifestations, which perfectly mimic epileptic seizures. Several patterns of neural abnormalities have been described without identifying a definite neurobiological substrate. In this multicenter cross-sectional study, we applied a multivariate classification algorithm on morphological brain imaging metrics to extract reliable biomarkers useful to distinguish patients from controls at an individual level. Twenty-three patients with PNES and 21 demographically matched healthy controls (HC) underwent an extensive neuropsychiatric/neuropsychological and neuroimaging assessment. One hundred and fifty morphological brain metrics were used for training a random forest (RF) machine-learning (ML) algorithm. A typical complex psychopathological construct was observed in PNES. Similarly, univariate neuroimaging analysis revealed widespread neuroanatomical changes affecting patients with PNES. Machine-learning approach, after feature selection, was able to perform an individual classification of PNES from controls with a mean accuracy of 74.5%, revealing that brain regions influencing classification accuracy were mainly localized within the limbic (posterior cingulate and insula) and motor inhibition systems (the right inferior frontal cortex (IFC)). This study provides Class II evidence that the considerable clinical and neurobiological heterogeneity observed in individuals with PNES might be overcome by ML algorithms trained on surface-based magnetic resonance imaging (MRI) data.

Proactive drugs in DFSA cases: Toxicological findings in an eight-years study.

In case of drug-facilitated sexual assault (DFSA), the evidence is frequently anecdotal, with few investigations based on scientific evidences being carried out and thus most cases are diagnosed as an acute drug or alcohol intoxication. The reason may lay in the lack of specific knowledge by the victim on the possibility to retrospectively study the allegedly events and to the absence of standardized and shared protocols among health, forensic and police subjects. On this basis, in 2015 the Unit of Forensic Toxicology of University of Florence and the Sexual Assaults Centre in Hospital Careggi have fixed a common protocol to be applied in case of DFSA. The purpose of the study was to describe the results of the application of the shared protocol for toxicological findings among women seeking health care after sexual assault, and to assess the relationship with so-called proactive DFSA drugs. We conducted a study on female patients above 18 years of age consulting the Sexual Assault Centre between 2010 and July 2018. Among the 256 patients included, 37.1% was positive at least for a substance. Alcohol was the most detected substance (57 cases), followed by Cannabis (19 cases), cocaine (15 cases) and opiates/methadone (heroine: 5; morphine:1; methadone: 6); benzodiazepines and amphetamine were found in 13 and in 2 cases, respectively. Only case of gamma-hydroxybutyrate (GHB) consumption was observed while new psychoactive substances were not detected. Among the patients suspecting proactive DFSA, sedative drug findings, not explained by voluntary intake, were encountered.

Sirolimus in Infants with Multiple Cardiac Rhabdomyomas Associated with Tuberous Sclerosis Complex.

INTRODUCTION: Cardiac rhabdomyomas represent a frequent manifestation of tuberous sclerosis. Tumor growth, mainly prenatally, can result in intrauterine fetal or neonatal deaths in almost 10% of patients. CASE REPORT: We treated 3 consecutive infants aged less than 12 months with sirolimus, an oral mTOR inhibitor. All patients achieved significant reductions in cardiac rhabdomyomas. A complete response was documented in 2 patients, while a partial response with tumor debulking greater than 50% was seen in the other one. The median time to best cardiac response was 1.9 months in all patients, and 3.3 months in those with complete response. The side effects profile was acceptable. CONCLUSION: Sirolimus may have a significant role in promoting natural regression of cardiac rhabdomyomas. Prospective clinical trials are needed.