Manifestations of X-linked pyruvate dehydrogenase complex deficiency in female PDHA1 carriers

Abstract

Background and purpose: Pyruvate dehydrogenase complex deficiency is in up to 90% caused by pathogenic variants in the X-linked PDHA1 gene. We aimed to investigate female relatives of index patients with PDHA1-related disease to (i) describe the prevalence of female PDHA1 carriers, (ii) determine whether they had symptoms and signs, and (iii) delineate the associated phenotype.

Methods: In a national population-based study, we identified 37 patients with pathogenic variants in PDHA1. Sanger sequencing for the presence of the pathogenic variant was performed in their mothers and female relatives. The identified female carriers were clinically assessed, and their medical records were reviewed.

Results: The proportion carrying a de novo variant was 86%. We identified seven female PDHA1 carriers from five families. Five of them exhibited clinical features of the disease and were previously undiagnosed; all had signs of peripheral axonal neuropathy, four presented with strokelike episodes including two with Leigh-like lesions, and three had facial stigmata.

Conclusions: PDHA1-related disease is underrecognized in heterozygous female carriers. Peripheral axonal neuropathy, strokelike and Leigh-like changes, and facial dysmorphism should raise suspicion of the disorder. Genetic analysis and clinical examination of potential female carriers are important for genetic counseling and have implications for treatment.

Keywords: PDHA1; PDHc deficiency; mitochondrial; peripheral axonal neuropathy; stroke.

FIGURE 1

Pedigrees of four families with maternally inherited PDHA1‐related mitochondrial pyruvate dehydrogenase complex (PDHc) deficiency.

FIGURE 2

Clinical and neuroradiological manifestations of mitochondrial pyruvate dehydrogenase complex deficiency related to age. Source: Adapted from Savvidou et al. 2022, Barnerias et al. 2010, Patel et al. 2012, Debrosse et al. 2012. m, months; MRI, magnetic resonance imaging; PVL, periventricular leukomalacia; yo, years old [4, 5, 14, 19].