Genetically Confirmed Case of Aspartylglycosaminuria (AGU)

Excerpt

To the Editor: Aspartylglycosaminuria (AGU) is a lysosomal storage disorder caused due to mutations in the AGA gene [1]. Clinically, the disorder is characterized by mucopolysaccharidosis (MPS) phenotype and radiologically by dysostosis multiplex [2]. A 9-y-old girl born of consanguinity, with uneventful birth history presented with developmental delay, behavioral abnormalities, and progressive abdominal distension from infancy. Child had hyperactivity, did not mingle with others, inappropriate laughing, open mouth, exaggerated startle, and needed assistance in her daily activities like dressing and bathing. On examination, weight: 29 kg (50th to 75th percentile), height: 129 cm (25th to 50th percentile), head circumference: 59 cm. Further, coarse facies, wide nasal bridge, muddy conjuctiva, short neck, open mouth, drooling of saliva, short stubby fingers, protruded abdomen, dry scaly skin and right knee contracture were noted. Systemic examination revealed inattention, dysarthria, spasticity, power of 4/5, exaggerated deep tendon reflexes in all limbs, and hepatosplenomegaly. On investigation, complete blood count, liver and kidney function tests, hearing assessment, skeletal survey and echocardiography, were normal. MRI brain showed corpus callosal thinning, hyperintensities in the bilateral periventricular region with cerebellar atrophy. Exome sequencing showed a novel likely pathogenic homozygous frameshift deletion c.831_835del, p.(Gly279fs*39) in exon-8 of AGA gene. Glycosylasparaginase activity from leukocytes showed deficiency, 0.9 nmol/24 h/mg [Normal: 53–122 (89 ± 20)]. …