Did you examine the parents?
The present case has been reported in the Journal of Pediatrics.

A 5-month-old boy presented to the Emergency Department with a febrile illness and respiratory distress of 4 days' duration. He had been delivered at term by cesarean delivery performed due to polyhydramnios, reduced fetal movements, and nonprogression of labor. After birth, he had frequent feeding problems, pooling of secretions, choking after feeds, and repeated hospitalizations for pneumonia.

Examination revealed normal head circumference, bitemporal hollowing, bifacial and bulbar weakness, inverted V-shaped upper lip, generalized hypotonia, reduced spontaneous antigravity movements, and hyporeflexia. He exhibited no tongue fasciculations or cardiomyopathy. Clinical differential diagnoses considered included congenital myopathy, spinal muscular atrophy, and congenital myotonic dystrophy.

On examination, the infant's mother showed the inability to open her hand after forceful fisting owing to delayed relaxation of the intrinsic hand muscles (grip myotonia), as well as persistent contraction on percussion (percussion myotonia sign).

The diagnosis of congenital myotonic dystrophy was confirmed by demonstration of expanded (>250) CTG repeat sequences.

Key takeaway:-
This case highlights that the simple maneuver of examining the parents may provide an important clue to the underlying neuromuscular condition in infants with hypotonia.

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