European ad-hoc consensus statement on gene replacement therapy for spinal muscular atrophy

Spinal muscular atrophy (SMA) used to be one of the most common genetic causes of infant mortality. New disease modifying treatments have changed the disease trajectories and most impressive results are seen if treatment is initiated in the presymptomatic phase of the disease. Very recently, the European Medicine Agency approved Onasemnogene abeparvovec (Zolgensma®) for the treatment of patients with SMA with up to three copies of the SMN2 gene or the clinical presentation of SMA type 1. While this broad indication provides new opportunities, it also triggers discussions on the appropriate selection of patients in the context of limited available evidence. To aid the rational use of Onasemnogene abeparvovec for the treatment of SMA, a group of European neuromuscular experts presents in this paper eleven consensus statements covering qualification, patient selection, safety considerations and long-term monitoring.

DMD and West syndrome

Duchenne Muscular Dystrophy (DMD) is the most frequent muscular dystrophy in childhood, with a worldwide incidence of one in 5000 live male births. It is due to mutations in the dystrophin gene leading to absence of full-length dystrophin protein. Central nervous system involvement is well-known in Duchenne Muscular Dystrophy. The multiple dystrophin isoforms expressed in brain have important roles in cerebral development and functioning. The association of Duchenne Muscular Dystrophy with seizures has been reported, and there is a higher prevalence of epilepsy in Duchenne Muscular Dystrophy patients (between 6.3% and 12.3%) than in the general pediatric population (0.5-1%). Duchenne Muscular Dystrophy patients may present with focal seizures, generalized tonic-clonic seizures or absences. We report on two boys in whom Duchenne Muscular Dystrophy is associated with epileptic spasms and hypsarrhythmia that fulfil the criteria for West syndrome, thus extending the spectrum of seizure types described in Duchenne Muscular Dystrophy patients.

Non-Ambulant Duchenne Patients Theoretically Treatable by Exon 53 Skipping have Severe Phenotype

BACKGROUND

Exon skipping therapy is an emerging approach in Duchenne Muscular Dystrophy (DMD). Antisense oligonucleotides that induce skipping of exon 51, 44, 45, or 53 are currently being evaluated in clinical trials. These trials were designed on the basis of data available in general DMD population.

OBJECTIVES

Our objective was to compare the clinical and functional statuses of non-ambulant DMD patients theoretically treatable by exon 53 skipping and of DMD patients with other mutations.

METHODS

We first compared fifteen non-ambulant DMD patients carrying deletions theoretically treatable by exon 53 skipping (DMD-53) with fifteen closely age-matched DMD patients with mutations not treatable by exon 53 skipping (DMD-all-non-53) then with fifteen DMD patients carrying deletions not treatable by exon 53 skipping (DMD-del-non-53).

RESULTS

We found that DMD-53 patients had a lower left ventricular ejection fraction, more contractures and they tend to have weaker grips and pinch strengths than other DMD patients. DMD-53 patients lost ambulation significantly younger than other DMD patients. This result was confirmed by comparing ages at loss of ambulation in all non-ambulant DMD patients of the DMD cohort identified in a molecular diagnostic lab.

CONCLUSIONS

These prospective and retrospective data demonstrate that DMD-53 patients have clinically more severe phenotypes than other DMD patients.

Elemente esenţiale în investigarea tulburării globale de dezvoltare şi a dizabilităţii intelectuale la copil

Obiective. Lucrarea subliniază modalităţile de investigare a etiologiei tulburării globale de dezvoltare (TGD), retardului mintal (RM) sau dizabilităţii intelectuale (DI) şi ordinea efectuării acestora. TGD şi RM/DI sunt entităţi cronice cu debut în perioada de dezvoltare, care afectează funcţiile personale, sociale, academice, ocupaţionale. Elucidarea etiologiei este importantă pentru stabilirea managementului, prognosticului, riscului de recurenţă, eventualelor posibilităţi de prevenţie şi pentru scăderea impactului psihoemoţional asupra familiilor. Material şi metodă. Literatura relevantă a fost revizuită, în prezent fiind publicate recomandări de abordare a pacienţilor cu TGD/RM, pornind de la un istoric complet, o examinare clinică minuţioasă, apoi formulând o suspiciune etiologică şi incluzând teste genetice, metabolice, neuroimagistice. Rezultate şi concluzii. Progresele din domeniul geneticii au modificat abordarea copilului cu TGD de etiologie neelucidată, crescând rata de identificare a anomaliilor cromozomiale patogenice. Hibridizarea genomică comparativă este recomandată de primă linie, cu cariotiparea ca investigaţie complementară. Secvenţierea permite analiza numeroaselor gene implicate în TGD, iar consultul genetic prioritizează investigaţiile. Identificarea diagnosticului etiologic oferă posibilitatea stabilirii unor planuri de management anticipativ, individualizat, în vederea limitării complicaţiilor şi comorbidităţilor asociate, pentru îmbunătăţirea calităţii vieţii pacienţilor.

Keypoints in investigating the child with global developmental delay and intellectual disability

Objective. This paper highlights the main lines of etiological investigation of global developmental delay (GDD), mental retardation (MR) or intellectual disability (ID) and their specific order. GDD and MR/ID are chronic entities with onset during the developmental period, affecting personal, social, academic, occupational functions. Elucidating the etiology is important for establishing the management, for assessing the outcome, the recurrence risk, potential opportunities for prevention and for decreasing the psycho-emotional impact on families. Material and method. Relevant literature was reviewed, currently being published recommendations for the diagnostic approach of children with GDD/MR, starting with a thorough history, a thorough clinical examination, then formulating a suspected etiology and including genetic, metabolic, neuroimaging testing. Results and conclusions. Advances in genetics have changed the approach of children with unexplained GDD, increasing the rate of pathogenic chromosomal abnormalities identification. Comparative genomic hybridization is recommended as first-line investigation, with karyotyping as complementary. Sequencing allows the study of many genes involved in GDD and genetic consultation prioritizes the investigations. The identification of the etiologic diagnosis offers the possibility of establishing anticipatory, individualized management plans, in order to limit the complications and associated comorbidities, thereby improving the quality of life.