Clinical correlations and long-term follow-up in 100 patients with sarcoglycanopathies.

BACKGROUND AND PURPOSE: To describe a large series of patients with α, ß, and γ sarcoglycanopathies (LGMD-R3, R4, and R5) and study phenotypic correlations and disease progression. METHODS: A multicentric retrospective study in four centers in the Paris area collecting neuromuscular, respiratory, cardiac, histologic, and genetic data. The primary outcome of progression was age of loss of ambulation (LoA); disease severity was established according to LoA before or after 18 years of age. Time-to-event analysis was performed. RESULTS: One hundred patients (54 γ-SG; 41 α-SG; 5 ß-SG) from 80 families were included. The γ-SG patients had earlier disease onset than α-SG patients (5.5 vs. 8 years; p = 0.022) and ß-SG patients (24.4 years). Axial muscle weakness and joint contractures were frequent and exercise intolerance was observed. At mean follow-up of 22.9 years, 65.3% of patients were wheelchair-bound (66.7% α-SG, 67.3% γ-SG, 40% ß-SG). Dilated cardiomyopathy occurred in all sarcoglycanopathy subtypes, especially in γ-SG patients (p = 0.01). Thirty patients were ventilated and six died. Absent sarcoglycan protein expression on muscle biopsy and younger age at onset were associated with earlier time to LoA (p = 0.021 and p = 0.002). Age at onset was an independent predictor of both severity and time to LoA (p = 0.0004 and p = 0.009). The α-SG patients showed genetic heterogeneity, whereas >90% of γ-SG patients carried the homozygous c.525delT frameshift variant. Five new mutations were identified. CONCLUSIONS: This large multicentric series delineates the clinical spectrum of patients with sarcoglycanopathies. Age at disease onset is an independent predictor of severity of disease and LoA, and should be taken into account in future clinical trials.

Paroxysmal strabismus and stridor acquired in childhood: Do not overlook calcemia!

Hypocalcemia is known to induce stridor but was rarely reported to cause strabismus. We report the case of a 4-year-old girl who presented with paroxysmal stridor and strabismus with diplopia, persisting for several weeks. Severe hypocalcemia (1.25 mmol/L) was finally diagnosed and was related to hypoparathyroidism, which was the first manifestation of autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) in this patient. Strabismus and stridor both resolved after normalization of calcemia. This case report is a rare observation of paroxysmal strabismus caused by hypocalcemia and it highlights the importance of calcium monitoring in any situation of atypical neurological symptoms.

Monoamine neurotransmitters and movement disorders in children and adults.

Neurotransmitter disorders comprise a rapidly expanding phenotypically and genetically heterogeneous group. Most of these disorders start in infancy through to childhood, although some forms may arise in adolescence and adulthood, and have various presentations. They may be overlooked if the phenotype leads to misdiagnoses involving various combinations of developmental disorders, hypotonia and movement disorders (dystonia, hyperkinesia, parkinsonism) or other clinical manifestations, such as sleep alterations and mood disorders. Neurotransmitter metabolite levels in cerebrospinal fluid (CSF) may help us to analyze and better understand the metabolic cascade and changes in dopamine and serotonin synthesis, and also guide genetic testing. Indeed, it is important to recognize these disorders in their early stages as they can be greatly improved by drug treatments, and if clinical responses are insufficient, then other agents that may enhance neurotransmission, such as serotonergic drugs and tetrahydrobiopterin (BH4) supplementation, could be considered. Also, a precise genetic diagnosis should be established by gene panels for dystonia, SNP microarrays and whole-exome sequencing. The present brief survey aims to review the present state of the art for the most commonly described and rare disorders of dopamine and serotonin, as well as cofactor deficiencies and dysfunctions, with an overview of clinical features, diagnostic strategies and treatments. Moreover, although these are mainly disorders of infants and children, many may nevertheless reach adulthood; thus, their evolution and treatments should be well known not only by pediatricians, but by neurologists as well, as the latter may be in charge at the stage of diagnosis (rarely) and during the follow-up of these rare patients.