<prompt> Give the most probable diagnosis of a 1 year. old child of normal intelligence with features of hypotonia. On examination, there are tongue fasciculations and he keeps his body in a frog-like positionGuillian Barre SyndromeLimb girdle atrophyDowns syndromeSpinal muscular atrophy  <response>: Features of hypotonic and frog-like position suggest the diagnosis of Floppy infant syndrome.Floppy infant syndromeIn FIS the baby is floppy i.e :He cannot hold his head up, there will be marked head lag as the baby is pulled up from supine to sitting posture.A normal infant, on ventral suspension i.e. supporting the infant with a hand under the chest keeps his back straight and head slightly up, arms abducted and knees partly flexed. A floppy infant droops, over the hand like an inverted U.Typical features Hypotonia and decreased muscular activityFrog-like posture or other unusual position at restDelay in motor milestonesCauses of Floppy infant syndromeCentral nervous systemPerinatal asphyxia, neonatal encephalopathy, kernicterus, cerebral palsy atonic type, intracranial haemorrhage, chromosomal anomalies including Down syndrome and inborn errors of metabolism e.g., aminoacidurias, mucopolysaccharidosis, and cerebral lipidosis.Spinal cord lesionsAnterior horn cell disease: Werdnig Hoffman spinal muscular atrophy, poliomyelitisPeripheral nervesAcute polyneuropathy, familial dysautonomia, congenital sensory neuropathyMyoneural junctionNeonatal myasthenia gravis, infantile botulism, following antibiotic therapyMusclesMuscular dystrophies, congenital myotonic dystrophies, congenital myopathies including central core disease and Nemaline myopathy, polymyositis, glycogen storage disease Pompes, and arthrogryposis multiplex congenitalMiscellaneousProtein-energy malnutrition, rickets, Prader-Willi syndrome, malabsorption syndromes, Ehler-Danlos syndrome, cutis laxa, cretinismComing back to questionThere are many causes of floppy infant syndrome.Out of the four option given in the question three of these can cause FIS -Downs syndromeGB. syndromeSpinal muscular atrophySpinal muscular atrophyFeatures of normal intelligence and tongue fasciculations strongly suggested spinal muscular atrophy. Downs syndromeCan be easily ruled out as intelligence is impaired in Downs syndrome.GB. syndromeCan be ruled out as it presents as an acute case with a past history of fever or viral infections.Majority of patients recover within a few days to 2 weeks. 