Dietary Treatment from Birth to Pregnancy in a Woman with Methylmalonic Aciduria

Abstract

Methylmalonic aciduria is treated with a natural protein-restricted diet with adequate energy intake to sustain metabolic balance. Natural protein is a source of methylmalonic acid precursors, and intake is individually modified according to the severity and clinical course of the disease. The experience and approach to MMA treatment in European centers is variable with different amounts of natural protein and precursor-free l-amino acids being prescribed, although the outcome appears independent of the use of precursor-free l-amino acids. Further long-term outcome data is necessary for early treated patients with MMA. This case study, a woman with MMA followed from birth to the age of 35 years, including pregnancy, illustrates the long-term course of the disease and lifetime changes in dietary treatment. A low natural protein diet (1.5 g–1.0 g/kg/day) was the foundation of treatment, but temporary supplementation with precursor-free l-amino acids, vitamin-mineral mixture, and energy supplements were necessary at different timepoints (in childhood, adolescence, adulthood and pregnancy). Childhood psychomotor development was slightly delayed but within the normal range in adulthood. There were few episodes of metabolic decompensation requiring IV glucose, but at age 27 years, she required intensive care following steroid treatment. In pregnancy, she remained stable but received intensive biochemical and medical follow-up. This successful long-term follow-up of a patient with MMA from childhood, throughout pregnancy, delivery, and postpartum confirms that careful clinical, biochemical, and dietetic monitoring is crucial to ensure a favourable outcomes in MMA. Personalized treatment is necessary according to the individual clinical course. Knowledge about long-term treatment and clinical outcome is important information to influence future MMA clinical guidelines.

Organic Aciduria Disorders in Pregnancy: An Overview of Metabolic Considerations

“…In almost all cases, intravenous dextrose was used to reduce the risk of metabolic decompensation. Intravenous carnitine was given during the delivery period in three cases [40,47,73]. There were no long-term complications for the MMA patients in the peripartum or postpartum periods.…”

“…The first case report of a patient with MMA who carried a pregnancy to term was reported in 1995 [48]. Complications during pregnancy included hyperammonaemia [51], nausea and vomiting [40,73], hyperglycaemia, anaemia [40,46,47], proteinuria [46], and carnitine deficiency [47]. One infant was noted to have poor foetal growth during the pregnancy with documented poor nutritional baseline prior to conception [38].…”

“…The protein restrictions for these case reports were described with increasing natural protein tolerance as the pregnancy advanced [40,42,46,50,73]. Precursor-free amino acids were utilised in two cases where insufficient natural protein intake was tolerated [38,40].…”

“…The protein restrictions for these case reports were described with increasing natural protein tolerance as the pregnancy advanced [40,42,46,50,73]. Precursor-free amino acids were utilised in two cases where insufficient natural protein intake was tolerated [38,40]. In one reported case, the addition of nocturnal corn starch was used dosing during pregnancy to prevent a fasting state and reduce the catabolism of odd-chain fatty acids [46].…”

“…There were no long-term complications for the MMA patients in the peripartum or postpartum periods. One case described a successful breastfeeding experience which was supported by a protein intake of up to 1.68 g/kg in addition to extra calories [40]. Cardiac complications and occult cardiomyopathies have been reported in PA patients [83,84].…”