Table 1. Patient Characteristics at Presentation and Follow-up

Age, years	ALT, IU/L	AST, IU/L	Reason for Metabolic Panel	Symptoms	Initial CK, IU/L	Muscle and Neurologic Symptoms at Presentation	Muscle and Neurologic Symptoms at Follow-up	Final Diagnosis
2	273	50	Tonsillitis	None	4,867	Calf hypertrophy	N/A	DMD/BMD
								Exon 45–47 deletion
<1	341	451	Failure to thrive	Failure to thrive	19,874	Calf hypertrophy	Wide-based gait, decreased reflexes	DMD/BMD
						Shoulder weakness		Exon 3–44 deletion
<1	246	497	Splenomegaly seen during routine physical	None	12,587	Hyperextensibility	N/A	DMD/BMD
						Head lag		Exon 3–29 deletion
6	477	324	Poor growth	Dark urine	12,121	None	Toe walking	Undiagnosed
5	>50	>40	Gastroenteritis	Short stature	14,752	Calf hypertrophy	Weakness	DMD
							Gower sign	Exon 49–54 deletion
11	140	94	Abdominal pain	Abdominal pain	5,833	Headaches	Headaches	BMD
								Exon 45–47 deletion
1	118	196	Feeding intolerance, failure to thrive	Failure to thrive, feeding intolerance	17,919	Developmental delay	Hearing loss	DMD/BMD
						Hypotonia, head lag, speech delay	Sleep apnea, head lag, Gower sign	Exon 8–11 deletion
3	497	318	Upper respiratory tract infection	None	22,009	Weakness,	Calf hypertrophy, weakness	DMD
						Decreased reflexes, hypotonia, Gower sign		Exon 20–25 deletion
2	300–400	300–400	Prolonged diarrhea	Chronic constipation, anemia	12,000	Calf hypertrophy	Fatigue, hypotonia, calf hypertrophy, Gower's sign	BMD/DMD
						Weakness		Exon 48–52 deletion
4	186	235	Leg pain, failure to thrive	Failure to thrive, abdominal pain, dark urine	9,932	Decreased mobility, limp	Fatigue, muscle cramping	Dystroglycanopathy
2	99	80	Urinary tract infection		917	None	Hyperextensibility	DMD/BMD carrier
								Heterozygous for exon 48–50 deletion
16	195	147	Unknown	None	12,131	None	None	Undiagnosed

Reference ranges: ALT, 0–50; AST, 0–40; γ-glutamyl transpeptidase, 5–55.
ALT, alanine aminotransferase; AST, aspartate aminotransferase; BMD, Becker muscular dystrophy; CK, creatinine kinase; DMD, Duchenne muscular dystrophy; IU/L, international units per liter.