Patient 3 is a 5-year-old male that presented with a two-vessel cord, PRS, cleft palate, and short femurs at birth. He failed the initial hearing test, and he spent the first 40 days of his life in the hospital for mandibular distraction. Mild developmental delay was noted, which was characterized mostly by speech delay, and articulation problems were present. Patient had HH and required frequent overnight feeding through a G-tube. At 2 years of age, the patient experienced an episode of a suspected seizure. However, his electroencephalogram (EEG) was unremarkable. Abnormal involuntary movements and central hypotonia were present. A transthoracic echocardiogram showed mild dilated mitral valve annulus, mild mitral valve insufficiency, severe left atrial dilation, and severe left atrial enlargement. He underwent tonsillectomy and adenoidectomy due to recurrent acute suppurative otitis media. Notable laboratory findings included recurrent abnormal coagulation parameters, elevated liver transaminases, increased CK levels and abnormal glycosylation in blood suggestive of CDG mixed type. Genetic testing revealed two pathogenic variants in PGM1 (c.265G > A; c.988G > C, see Table 1) confirming the diagnosis of PGM1-CDG. At 3 years of age, D-gal has been started (current dose 1.8 g/kg/day in two doses). In addition, cornstarch (2x 1 tbs; approximately 30 g) has been prescribed to further manage hypoglycemia, which has resolved since starting the treatment. CK levels likewise normalized. Moreover, D-gal significantly improved serum transferrin glycosylation and coagulation parameters (Figure 1). Liver transaminases improved but did not normalize. Cardiac presentation did not improve.