3-Hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) lyase deficiency in Saudi Arabia.

Deficiency of 3-hydroxy-3-methylglutaryl-CoA lyase has been studied in 11 Saudi infants. The diagnosis was established by the measurement of enzyme activity in lymphocytes, in fibroblasts and, in seven patients, by the gas chromatography/mass spectrometer pattern of excreted organic acids in the urine. In seven infants the disease caused a devastating acidotic attack within the first day of life, while in two the crisis occurred by the third day of life. In two infants from one family the disease appeared later in infancy. The clinical presentation of an acidotic attack is lethargy, hyperpnoea, tachypnoea and seizures, either at birth (two infants), following first feeding (in five infants), or following vomiting or refusal of food in later infancy. The acidotic attacks recurred later in life following minor illness or refusal to eat. The acidosis of this enzyme deficiency progresses rapidly, leading to cardiopulmonary arrest and death within hours of onset unless treated promptly. In four surviving infants diagnosed and treated early, development is normal. Magnetic resonance and computerized tomography brain scans in these infants, however, show white matter lesions and mild atrophy.