Robert Griggs

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A kindred in which at least 11 individuals in 3 consecutive generations have continuous muscle movement, i.e., myokymia, and periodic ataxia, has been studied. Three patients, a 24-year-old woman, her 4-year-old son and her 27-year-old sister, have been studied in detail. The disorder is inherited as an autosomal-dominant trait and presents in early(More)
The non-dystrophic myotonias are an important group of skeletal muscle channelopathies electrophysiologically characterized by altered membrane excitability. Many distinct clinical phenotypes are now recognized and range in severity from severe neonatal myotonia with respiratory compromise through to milder late-onset myotonic muscle stiffness. Specific(More)
The periodic paralyses are a group of autosomal dominant muscle diseases sharing a common feature of episodic paralysis. In one form, paramyotonia congenita (PC), the paralysis usually occurs with muscle cooling. Electrophysiologic studies of muscle from PC patients have revealed temperature-dependent alterations in sodium channel (NaCh) function. This(More)
We describe a congenital myasthenic syndrome associated with severe end-plate (EP) acetylcholine receptor (AChR) deficiency not associated with an EP myopathy, and with evidence of immature AChR, containing the gamma instead of the epsilon subunit (gamma-AChR) at the EPs. Molecular genetic analysis of AChR-subunit genes revealed two mutations in the(More)
Periodic paralyses (PPs) are rare inherited channelopathies that manifest as abnormal, often potassium (K)-sensitive, muscle membrane excitability leading to episodic flaccid paralysis. Hypokalaemic (HypoPP) and hyperkalaemic PP and Andersen-Tawil syndrome are genetically heterogeneous. Over the past decade mutations in genes encoding three ion channels,(More)
We report 3 patients from 2 families with myotonic dystrophy who do not show an abnormal expansion of CTG trinucleotide repeats within the myotonic dystrophy gene. Characteristic features of myotonic dystrophy in these patients were frontal balding, cataracts, cardiac conduction abnormalities, and testicular atrophy with myotonia and muscle weakness.(More)
BACKGROUND Periodic paralyses and paramyotonia congenita are rare disorders causing disabling weakness and myotonia. Mutations in sodium, calcium, and potassium channels have been recognized as causing disease. OBJECTIVE To analyze the clinical phenotype of patients with and without discernible genotype and to identify other mutations in ion channel genes(More)
We have studied the effect of a pharmacological dose of testosterone enanthate (3 mg.kg-1.wk-1 for 12 wk) on muscle mass and total-body potassium and on whole-body and muscle protein synthesis in normal male subjects. Muscle mass estimated by creatinine excretion increased in all nine subjects (20% mean increase, P less than 0.02); total body potassium mass(More)
We performed a randomized, double-blind, controlled six-month trial of prednisone in 103 boys with Duchenne's muscular dystrophy (age, 5 to 15 years). The patients were assigned to one of three regimens: prednisone, 0.75 mg per kilogram of body weight per day (n = 33); prednisone, 1.5 mg per kilogram per day (n = 34); or placebo (n = 36). The groups were(More)