MEDIUM CHAIN ACYL-CoA DEHYDROGENASE DEFICIENCY WITH
ABSENCE OF HYPOGLYCEMIA AND PRESENCE OF KETOSIS
Gutiérrez C., Ruiz R., TebarR., Vidal A, Lillo M..
Onsurbe I.
Pediatric Department. General Hospital. Albacete.
Spain
INTRODUCTION:
Medium chain acyl-coA dehydrogenase (MCAD) deficiency is the most common
hereditary defect of fatty oxidation in humans. Its entity is always included
in the differential diagnosis of non-ketotic hypoglycemia, although it is
believed to be considerable underdiagnosed. The detection is relevant, as death
is the outcome of the first attack in 25% cases. A point mutation (A to G
[corrected] at position 985) of the MCAD gene represents more than 90% of
alleles causing deficiency. The frequency of this allelic variant exhibits
considerable geographical variation. In Spain, the frequency is low as occurs
in other Southern European countries, except in the gypsy community.
CASE REPORT:
a 2 years old boy of gypsy origin is admitted to the hospital with repeated
vomiting and encephalopathy. Parents are firs degree cousins, there are no
previous sibling deaths. On physical exam weight and height are below 3rd percentile,
there is hepatomegaly (6 cm below r.c.m.). Laboratory values :
metabolic acidosis, glucose : 108 mg/dl, ammonium: 144
mmol/L, ALT 196 U/L, AST 183 U/L, LDH 2452 U/L. albumin 2,8 g/dl. Urine
ketones: 50 mg/dl. Chest x-ray: diffuse bronchopneumonia, abdominal CT scan :
marked hepatomegaly with fat density. Sweat test, antigliadin and antiendomysium
antibodies, antibodies to HVA.HVB.HVC negative. Urine : high levels of medium
chain dicarboxilic acids and hexanoil-glycine and suberil-glycine . Serum :
total and free camitin levels undetectable, high levels of medium chain fatty
acid. Genetic study : patient homozygous for K304E (A 985 G) mutation.
CONCLUSIONS:
MCAD deficiency should be included in the differential diagnosis of liver
steatosis in childhood, the absence of hypoglycemia and the presence of ketosis
do not rule out the diagnosis of this inborn error of metabolism.