Usher syndrome with methylmalonic acidemia and homocysteine in an infant

VernacularTitle:Usher综合征伴合并型甲基丙二酸血症1例
Author: Yujuan WANG ¹ ; Jinjun TIAN ; Linyuan NIU ; Liqin LIU ; Xinqiang LAN
Author Information

1. 青岛大学附属威海医院（威海市妇幼保健院）医学遗传科，威海　264200
Keywords: Usher syndromes; Amino acid metabolism, inborn errors; Methylmalonic acid
From: Chinese Journal of Perinatal Medicine 2022;25(12):975-977
CountryChina
Language:Chinese
Abstract: A case of Usher syndrome with methylmalonic acidemia and homocysteine is reported. The patient was a two-month-old and small for gestational age male infant hospitalized for "feeding difficulties" during the neonatal period. The baby boy presented hypotonia, microcephaly, and hearing loss after birth. Genetic test found compound heterozygous mutations of c.482G>A and c.567dup in MMACHC, and both were pathogenic mutations inherited from his parents. Moreover, the patient also had compound heterozygous variants at c.2802T>G and c.14017T>C of USH2A gene. The former was suspected to be pathogenic, and the latter was of unknown clinical significance. Both were from the parents. Usher syndrome and methylmalonic acidemia with homocysteine were clinically diagnosed. Followed up to the age of two, the child was found with moderate mental retardation, while the physical development was comparable to that of the same age group.