A case of Hb Rothschild ( HBB : c.112T>A) with low pulse oximetry: a first familial presentation in China.

A 37-year-old Chinese man complained of recurrent dyspnea, with low pulse oximetry (SpO 2 ) and normal partial pressure of oxygen (PaO 2 ) by blood gas analysis. The patient's P 50 was elevated at 47.3 mmHg, while hemoglobin fraction by capillary electrophoresis revealed an abnormal HbD quantified at 43.2%. Further DNA analysis by whole exome sequencing (WES) identified heterozygosity for a mutation in exon 2 at codon 38 ( HBB : c.112T>A, p.Trp38Arg), which decodes to a substitution of the amino acid tryptophan (Try) by arginine (Arg), known as Hb Rothschild. The patient's mother and daughter were also diagnosed to have low SpO 2 readings and his daughter was confirmed to carry Hb Rothschild. This is the first known familial case of Hb Rothschild in China. As Hb Rothschild may be underdiagnosed in Asian descent, better understanding in this area would help avoid unnecessary cardiorespiratory interventions.