TY - JOUR
T1 - Type 1 fiber size disproportion
T2 - Morphometric data from 37 children with myopathic, neuropathic, or idiopathic hypotonia
AU - Lannaccone, Susan T.
AU - Bove, Kevin E.
AU - Vogler, Carole A.
AU - Buchino, John J.
N1 - Funding Information:
Supported in part by grants from the Muscular Dystrophy Association and the March of Dimes Foundation (STI) and by USPHS grant RR-00123 from the General Clinical Research Centers Branch, Division of Research Resources, NIH. Address reprint requests to Susan T. Iannaccone, M.D., Division of Pediatric Neurology, Children's Hospital Medical Center, Cincinnati, Ohio 45229.
PY - 1987
Y1 - 1987
N2 - We reviewed clinical data and quantitative muscle biopsy data from infants with hypotonia and developmental delay who had relatively small type I muscle fibers (fiber size disproportion; FSD). Study material consisted of 49 thigh muscle specimens from 37 patients, 1 week to 11.5 years old, who had FSD diagnosed between 1971 and 1985. Beyond 2 months of age, FSD was >12% in at least one biopsy from all but 2 patients. In sequential specimens obtained from 11 patients, we observed that FSD may resolve, persist unchanged, or intensify with age. In 6 patients, hypotonia regressed, and development tended to normalize during 1 - 4 years of observation; FSD resolved in 4 cases, but numerical predominance of type 1 fibers persisted in 3 of them. In a small group designated congenital myopathy with FSD only, the disproportion in fiber diameter persisted unchanged or intensified with time and was more severe after the age of 6 months than in the other subgroups. We classified FSD as definitely or probably myopathic (15 cases), definitely or probably neuropathic (17 cases), and benign maturation delay (5 cases). Six of 17 neuropathic cases had a history of perinatal asphyxia. In most cases, type 1 fibers were absolutely small and type 2 fibers were hypertrophied, independent of classification. FSD is a manifestation of muscle maturation delay of variable etiology. The prevalence of nervous system disorders in our series suggests that neuronal dysfunction plays an important role in pathogenesis. We were unable to define morphometric criteria that consistently distinguished congenital myopathy with FSD from definable neuropathic FSD or from benign maturation delay..
AB - We reviewed clinical data and quantitative muscle biopsy data from infants with hypotonia and developmental delay who had relatively small type I muscle fibers (fiber size disproportion; FSD). Study material consisted of 49 thigh muscle specimens from 37 patients, 1 week to 11.5 years old, who had FSD diagnosed between 1971 and 1985. Beyond 2 months of age, FSD was >12% in at least one biopsy from all but 2 patients. In sequential specimens obtained from 11 patients, we observed that FSD may resolve, persist unchanged, or intensify with age. In 6 patients, hypotonia regressed, and development tended to normalize during 1 - 4 years of observation; FSD resolved in 4 cases, but numerical predominance of type 1 fibers persisted in 3 of them. In a small group designated congenital myopathy with FSD only, the disproportion in fiber diameter persisted unchanged or intensified with time and was more severe after the age of 6 months than in the other subgroups. We classified FSD as definitely or probably myopathic (15 cases), definitely or probably neuropathic (17 cases), and benign maturation delay (5 cases). Six of 17 neuropathic cases had a history of perinatal asphyxia. In most cases, type 1 fibers were absolutely small and type 2 fibers were hypertrophied, independent of classification. FSD is a manifestation of muscle maturation delay of variable etiology. The prevalence of nervous system disorders in our series suggests that neuronal dysfunction plays an important role in pathogenesis. We were unable to define morphometric criteria that consistently distinguished congenital myopathy with FSD from definable neuropathic FSD or from benign maturation delay..
KW - Benign congenital hypotonia
KW - Central hypotonia
KW - Congenital muscular dystrophy
KW - Congenital myopathy
KW - Fiber size disproportion
KW - Muscle morphometry
KW - Perinatal osphyxia
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U2 - 10.3109/15513818709161403
DO - 10.3109/15513818709161403
M3 - Article
C2 - 2451237
AN - SCOPUS:0023620668
SN - 1551-3815
VL - 7
SP - 395
EP - 419
JO - Fetal and Pediatric Pathology
JF - Fetal and Pediatric Pathology
IS - 4
ER -