Identification of a Novel Pathogenic Variant in the NAGLU Gene in a Child with Neurodevelopmental Delay.
This lab report names the exact gene glitch behind one child’s Sanfilippo B; it offers no behavior data for clinicians.
01Research in Context
What this study did
Doctors sequenced the DNA of a child with global delays. They hunted for tiny spelling errors in the NAGLU gene.
Five new mutations popped up. These changes cause Sanfilippo syndrome type B, a rare storage disorder.
What they found
The team pinned the child’s problems on the NAGLU gene. No behavior data were collected.
The paper ends at the lab bench. It tells you the ‘why’ behind the delays, not how to treat them.
How this fits with other research
Cohen et al. (2005) already list Sanfilippo B in their autism gene screen. Pia’s new mutations simply add five more lines to that same checklist.
Estécio et al. (2002) found a large share of Brazilian youths with PDDs had clear chromosomal quirks. Pia’s case says, ‘Keep looking—single-gene errors count too.’
Mertz et al. (2014) tracked Angelman kids for 12 years and tied deletion size to outcome. Pia stops at diagnosis; it doesn’t predict long-term skills.
Why it matters
If a child shows steady loss of language plus hyperactivity, ask the pediatrician about Sanfilippo screening. Early gene confirmation won’t change your ABA plan today, but it opens the door to future enzyme trials and gives the family a real answer.
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02At a glance
03Original abstract
The Sanfilippo syndrome type B is a lysosomal storage disorder caused by deficiency of alpha-N-acetylglucosaminidase; it is characterized by profound mental deterioration in childhood and death in the second decade. For understanding the molecular genetics of the disease and for future development of DNA-based therapy, we have cloned the cDNA and gene encoding alpha-N-acetylglucosaminidase. Cloning started with purification of the bovine enzyme and use of a conserved oligonucleotide sequence to probe a human cDNA library. The cDNA sequence was found to encode a protein of 743 amino acids, with a 20- to 23-aa signal peptide immediately preceding the amino terminus of the tissue enzyme and with six potential N-glycosylation sites. The 8.5-kb gene (NAGLU), interrupted by 5 introns, was localized to the 5'-flanking sequence of a known gene, EDH17B, on chromosome 17q21. Five mutations were identified in cells of patients with Sanfilippo syndrome type B: 503del10, R297X, R626X, R643H, and R674H. The occurrence of a frameshift and a nonsense mutation in homozygous form confirms the identity of the NAGLU gene.
Journal of autism and developmental disorders, 2022 · doi:10.1073/pnas.93.12.6101