Profound Biotinidase deficiency caused by (D444H) resulting in recurrent early childhood death in a Sudanese Family

Reem Salaheldin  Khalid Hamad; rayan Saif; rayan Khalid; muntaser E. Ibrahim; imad Fadl-elmula

doi:10.5455/JMRR.20241019032519

Abstract
Introduction
Biotinidase deficiency (BTD) is an autosomal recessive disease in which biotin recycling from biocytin or biotinylated peptides is impaired. The disorder is a result of the deficient or absent activity of Biotinidase.
Material and methods
Two healthy parents presented with a history of two daughters who had neurological, cutaneous, and respiratory manifestations and died in early childhood. They also had two healthy living daughters (8 and 4 years old).
Whole exome sequencing was done for the mother, and then specific BTD gene sequencing was done for the father, which was analyzed using bioinformatic tools.
Results
Whole exome sequencing analysis of the mother genomic DNA showed heterozygous missense mutation in the BTD gene with rs 13078881. Subsequent specific BTD gene sequencing identified an Identical mutation in the fathers’ genomic DNA.
Discussion
The present mutation behaved unusually since it caused profound Biotinidase deficiency in the homozygous state. According to our knowledge, this is the first case of profound Biotinidase deficiency in the homozygous state to be reported.
Conclusion
In the absence of neonatal screening programs, whole genome sequencing remains an effective way of diagnosing metabolic Mendelian disorders in underdeveloped countries.

Key words: Biotinidase deficiency, early childhood death, Sudan