Analysis and follow-up of 28 children with methylmalonic acidemia combined with renal damage / 中华实用儿科临床杂志

ABSTRACT

Objective To understand the clinical characteristics, treatment effect and prognosis of children with methylmalonic acidemia (MMA) combined with renal damage, and to provide experiences about how to improve the level of diagnosis and treatment.Methods The medical records of children with MMA were collected from January of 2007 to December of 2013 in Beijing Children's Hospital Affiliated to Capital University of Medical Sciences,while the clinical manifestations,laboratory findings, imaging material, inspection results were analyzed, and the renal pathological gene analysis, treatment effect, and prognosis of MMA children with renal damage were studied, and follow-up was carried out for 3 months up to 7 years.Results Among the two hundred and ninety-six cases of MMA,28 cases (9.5％) with renal damage,including 19 boys and 9 girls, 18 patients with hyperhomocysteinemia.Their ages varied from 2 days to 13 years old when confirmed.The first symptoms of 16 cases were proteinuria, hematuria, and edema, 9 cases were complicated with acute renal failure,5 cases were diagnosed as hemolytic uremic syndrome,6 patients were diagnosed as nephrotic syndrome, receiving enough glucocorticoids treatment without improvement.The routine examination of the urine showed that proteinuria (241-3 060 mg/d), methylmalonic acid levels and urinary protein were positively correlated (r =0.982, P =0.003), as urinary β2-microglobulin [(360.386 ± 231.496) μg/L], retinol binding protein [(338.537 ± 243.293) μg/L] increased.Extrarenal clinical manifestations were the spiritual, mental and physical development retardations, seizures, anemia etc.Two cases had a positive family history.Renal pathology showed mesangial cells and mesangial matrix proliferation broadening, no electron dense deposits in mesangial area, renal tubular epithelial cell swelling degeneration, and immunofluorescence was negative.Gene analysis of 3 cases showed exon1c.80A ＞ G,p.Q27R and exon1c.365A ＞ T,p.H122L/c.609 G ＞ A,p.W203X.Children with MMA were treated with vitamin B12 treatment.Two cases of multiple organ failure died during hospitalization, and 2 cases died after leaving hospital.After treatment, the level of urinary methylmalonic acid was significantly decreased, while nervous system symptoms improved significantly, and the mental state and the renal function were improved.Conclusions MMA may be associated with kidney damage,usually with severe renal tubular and glomerular impairment.Early diagnosis is the key,and timely treatment can effectively control the disease, improve the prognosis.