Recurrent Skin Ulcers with Facial Dysmorphism and Sinopulmonary Infections: Thinking Beyond Hyper-IgE Syndrome

Prolidase deficiency (PD) is a rare inborn error of metabolism causing ulcers and other skin disorders, splenomegaly, developmental delay, and recurrent infections. Most of the literature is constituted of isolated case reports. It occurs due to the mutations in the prolidase gene (PEPD) that result in loss of prolidase activity. We reported here a child who had presented with features compatible with hyper-immunoglobulin E syndrome (HIES) like recurrent skin ulcers, recurrent infections, facial dysmorphism, retained primary teeth, and elevated levels of immunoglobulin E levels but with normal flow cytometric assays, which was later diagnosed as PD.

Prolidase deficiency in an infant with an incidental finding of methaemoglobinaemia

A 4-week-old boy presented to the hospital with symptoms of diarrhoea and vomiting initially thought to be due to cow’s milk allergy. He was discharged with extensively hydrolysed formula. The patient represented with worsening of symptoms with metabolic acidosis and was screened and treated for sepsis. However, his condition deteriorated further and he developed methaemoglobinaemia. He was transferred to the high dependency unit and was given two doses of methylene blue. Further investigations were carried out, including rapid trio exome sequencing, which identified a homozygous pathogenic Peptidase D (PEPD) variant (c.978G>A, p.(Trp326*)). This was consistent with a diagnosis of prolidase deficiency.