Congenital and childhood myotonic dystrophy: Current aspects of disease and future directions

Table 2 Summary of the clinical manifestations in congenital and childhood-onset/juvenile myotonic dystrophy type 1

System	Congenital (CDM)	Childhood-onset/juvenile onset
Prenatal	Polyhydramnios	Not applicable
	Reduced foetal movements
	Preterm delivery
Muscular	Hypotonia at birth	Facial dysmorphia (may be subtle)
	Talipes	Generalised muscle weakness
	Contractures	Myotonia, usually after 1st decade
	Scoliosis, lordosis, kyphosis	Muscle atrophy
	Arthrogryposis	Brisk reflexes
	Characteristic facial dysmorphia	Mild talipes and contractures Motor delay
	Hyporeflexia
	Generalised muscle weakness (distal > proximal)
	Muscle atrophy
	Motor delay
Vision	Visual impairment	Visual impairment
	Strabismus	Strabismus
	Reduced visual acuity	Reduced visual acuity
	Lens pathology	Lens pathology
Respiratory	Respiratory distress at birth	Recurrent infections (weak cough)
	Raised right hemi-diaphragm	Sleep apnoea and sleep disordered breathing
	Pulmonary hypoplasia
	Bronchopulmonary dysplasia
	Aspiration pneumonia
	Sleep apnoea and sleep disordered breathing
	Pneumothorax
	Recurrent infections
	Impaired central respiratory control
Gastrointestinal and feeding	Sucking difficulties from birth	Recurrent abdominal pain
	Gastroparesis
	Gastroesophageal reflux and aspiration
	Constipation
	Recurrent diarrhoea
	Faecal incontinence
	Anal dilatation
	Persistent abdominal pain
CNS	Increased sensitivity to anaesthesia	Hypersomnolence and fatigue
	Neuroendocrine disturbance	Periodic limb movements
	Psychiatric disorders (ADHD, anxiety, depression)	Psychiatric disorders
	Autism	Autism
	Hypersomnolence and fatigue
Cognitive function	Lower IQ	Lower IQ
	Full scale ranges between 40-80	Full scale ranges from 42 to 114
	Mean less than 70	Mean between 70 and 80
Cardiac	Conduction disturbances	Conduction disturbances
	Structural abnormality, valve defects (most commonly mitral)	Structural abnormality, valve defects
		(More common in older patients)
Endocrine	Testicular atrophy	Testicular atrophy
	Hormone abnormalities: growth hormone, hypothyroidism (late teens)	Later onset: hormone abnormalities
Hearing	Recurrent otitis media	Recurrent otitis media (less common)
Oral health	Dental caries, plaque, gingivitis decay/trauma	Dental caries, plaque, gingivitis decay/trauma
Speech and language	Nasal voice and dysarthria	Speech delay
	Speech delay	Nasal voice and dysarthria
Life expectancy	30%-40% death rate within neonatal period	Mortality similar to adult-onset
	Mean life expectancy: 45 yr	Mean life expectancy: approximately 60 yr

CDM: Congenital myotonic dystrophy; ADHD: Attention-deficit/hyperactivity disorder; CNS: Central nervous system; IQ: Intelligence quotient.