Abstract
Isolated methylmalonic acidurias comprise a heterogeneous
group of inborn errors of metabolism caused by defects of
methylmalonyl-CoA mutase (MCM) (mut0, mut-) or deficient
synthesis of its cofactor 5'-deoxyadenosylcobalamin
(AdoCbl) (cblA, cblB). The aim of this study was to compare
the long-term outcome in patients from these four enzymatic
subgroups. Eighty-three patients with isolated
methylmalonic acidurias (age 7-33 y) born between 1971 and
1997 were enzymatically characterized and prospectively
followed to evaluate the long-term outcome (median
follow-up period, 18 y). Patients with mut0 (n = 42), mut-
(n = 10), cblA (n = 20), and cblB (n = 11) defects were
included into the study. Thirty patients (37\%) died, and
26 patients survived with a severe or moderate neurologic
handicap (31\%), whereas 27 patients (32\%) remained
neurologically uncompromised. Chronic renal failure (CRF)
was found most frequently in mut0 (61\%) and cblB patients
(66\%), and was predicted by the urinary excretion of
methylmalonic acid (MMA) before CRF. Overall, patients with
mut0 and cblB defects had an earlier onset of symptoms, a
higher frequency of complications and deaths, and a more
pronounced urinary excretion of MMA than those with mut-
and cblA defects. In addition, long-term outcome was
dependent on the age cohort and cobalamin responsiveness.
- 12,
- acid
- acid,
- adolescent;
- adult;
- age
- alkyl
- amino
- and
- aryl
- b
- child;
- chronic,
- cobamides,
- complex,
- complications/drug
- disease
- disease;
- diseases,
- errors,
- estimate;
- etiology;
- factors;
- failure,
- female;
- follow-up
- gastrointestinal
- genetic
- genetics/metabolism;
- humans;
- inborn
- kaplan-meiers
- kidney
- male;
- membrane
- metabolism,
- metabolism/urine;
- metabolism;
- methylmalonic
- methylmalonyl-coa
- mitochondrial
- mutase,
- mutation;
- nervous
- of
- onset;
- predisposition
- prognosis;
- progression;
- prospective
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