Congenital muscular dystrophy type 1B.
Incidence
Autosomal recessive. Rare. These autosomal recessive diseases affect both sexes equally.
Clinical Characteristics
Characteristic features are onset in infancy with delayed motor milestones; acquisition of ambulation; muscle hypertrophy; axial muscle weakness and respiratory insufficiency, and markedly elevated serum CK. Patients present in the first year, with hypotonia and weakness. Motor milestones are delayed, but ambulation is achieved by 3 years. Limb-girdle and facial weakness are prominent. Muscle hypertrophy is common. Respiratory failure leads to death or the need for ventilatory assistance. Intelligence and brain MRIs are normal. It is due to defects of glycosyltransferases (dystroglycanopathies).
Precipitants
The usual precautions that should be observed for all patients with a muscular dystrophy and elevated serum CK should be followed in these conditions.
Provocation Tests
None
Diagnostic Procedures
Mainly clinical. This condition was assigned to chromosome 1q in two informative families (linked to chromosome region 1q42).