Current understanding and progress of research on isovaleric acidemia / 中华医学遗传学杂志

Isovaleric acidemia is a type of organic acidemia for which the earliest definite diagnosis was attained. It features an autosomal recessive inheritance, with the onset of age varying from newborn to adulthood. The clinical manifestations are complex and variable, which include feeding difficulty, vomiting, lethargy, coma, metabolic acidosis, sweaty feet odor and mental retardation. The mortality and mobility rates of isovaleric acidemia are quite high, and early diagnosis and rational treatment can significantly improve the prognosis. This article has provided a summary for the current understanding and research progress on isovaleric acidemia.

Isovaleric acidemia due to compound heterozygous variants of IVD gene in a case / 中华医学遗传学杂志

OBJECTIVE@#To analyze the clinical features, biochemical characteristics and molecular pathogenesis of a girl with isovaleric acidemia.@*METHODS@#Clinical features, blood spot amino acid profiles and urinary organic acid profiles of the patient were analyzed. Targeted capture, next generation sequencing and Sanger sequencing were carried out to detect potential variant of the IVD gene.@*RESULTS@#The patient presented with poor weight gain, poor feeding, lethargy, and a "sweaty feet" odor 10 days after birth. Biochemical test suggested hyperammonemia. Blood spot amino acid profiles displayed a dramatic increase in isovalerylcarnitine (C5: 3. 044, reference range 0.04 - 0.4 μmol/L). Organic acid analysis of her urine sample revealed a high level of isovaleric glycine (669. 53, reference range 0 - 0.5). The child was ultimately diagnosed with isovaleric acidemia, and was found to harbor a paternally derived heterozygous variant c.149G>A (p.R50H) and a maternally derived heterozygous variant c.1123G>A (p.G375S) of the IVD gene. Her elder brother was a heterozygous carrier of c.1123G>A (p.G375S) variant. The c.149G>A (p.R50H) was a known pathogenic variant, while the c.1123G>A (p.G375S) variant was previously unreported.@*CONCLUSION@#The pathogenesis of the patient was delineated from the perspective of genetics, which has provided a basis for clinical diagnosis, treatment as well as genetic counseling.

Screening and clinical analysis of isovaleric acidemia newborn in Zhejiang province / 浙江大学学报·医学版

OBJECTIVE@#To investigate the incidence,clinical,biochemical and genetic characteristics of isovaleric acidemia (IVA) in Zhejiang province.@*METHODS@#Between January 2009 and December 2019, a total of 3 510 004 newborns were screened for IVA using tandem mass spectrometry. Patients of IVA were confirmed by urine organic acid and @*RESULTS@#A total of 15 patients with IVA were diagnosed, with an incidence of 1/234 000. Three patients had acute neonatal IVA, and the rest were asymptomatic. The isovalerylcarnitine (C5) levels were increased in all patients. Twelve children underwent urinary organic acid analysis, of which 11 cases had elevated isovalerylglycine levels, 4 cases with 3-hydroxyisovalerate increased simultaneously. Eleven IVA patients underwent genetic testing, 9 patients were compound heterozygous variants in @*CONCLUSIONS@#The clinical manifestations of IVA are non-specific, and the gene spectrum is scattered. Newborn patients screened by tandem mass spectrometry can receive early diagnosis and treatment, so as to correct metabolic defects and pathophysiological changes.