Direct sequencing of β-globin gene reveals a rare combination of two exonic and two intronic variants in a β-thalassemia major patient: a case report

Table 1 All the variants, with their Human Genome Variation Society (HGVS) nomenclature, present in this rare compound heterozygous condition

Variants/SNV	HGVS nomenclature	Position on gene	Amino acid substitution	Ref. allele frequency (global)^a	Clinical significance^b
CD 3 (T>C); rs713040	HBB:c.9T>C	Exon 1	Histidine>Histidine	0.16030	Benign
CD 41/42 (-CTTT); rs80356821	HBB:c.126_129delCTTT	Exon 2	Frameshift (F42fs)	0.000278	Pathogenic (premature termination codon)
IVS-II-16 (G>C); rs10768683	HBB:c.315 + 16G>C	Intron 2	Intronic Variant	0.16670	Likely-benign, Benign
IVS-II-666 (C>T); rs1609812	HBB:c.316 − 185C>T	Intron 2	Intronic Variant	0.169423	Benign

Data from dbSNP^a and ClinVar^b were used for reference allele frequency (global) and clinical significance, respectively

ISSN: 1752-1947