Hypoparathyroidism, neutropenia and nephrotic syndrome in a patient with mitochondrial trifunctional protein deficiency: A case report and review of the literature

Mitochondrial trifunctional protein (TFP) deficiency is an autosomal recessive disorder that causes a clinical spectrum of diseases ranging from severe infantile cardiomyopathy to mild chronic progressive neuromyopathy, however, parathyroid glands, hematologic system and kidney damage are not the common presentations of this disease.We describe the clinical, biochemical and molecular features of the TFP deficiency patient at our institution. We also provide an extensive literature review of previous published cases with emphasis on the clinical/biochemical phenotype-genotype correlation of this disorder.Our case is a complete TFP deficiency patient dominated presented with hypoparathyroidism, neutropenia and nephrotic syndrome, which caused by compound heterozygoues variants in HADHB gene. Based on the retrospective study of 157 cases, TFP patients presented with diverse clinical, biochemical and molecular features. The onset age is typically before early childhood. Neuromuscular system is more vulnerable involved. Severe form is generally characterized by multiorgan involvement. A notable feature of severe and intermediate form is respiratory failure. Neuropathy and rhabdomyolysis are the typical manifestations of mild form. Increased long-chain 3-OH-acylcarnitines (C16-OH, C18:1-OH) are the most common biochemical finding. The mortality of the present study is as high as 57.9%, which is linked with the onset age, phenotype, mutation type and muscular histology. Mutations in HADHB are more frequent in Asian descent with complete TFP deficiency and usually presented with atypical presentations. The type of mutation, rather than residual enzyme activity seem to be more related to the phenotype and prognosis. The most common HADHA variant is 1528G > C, no common HADHB variant were detected.TFP deficiency is heterogeneous at both the molecular and phenotypic levels, generally a high mortality. Although there is no strict clinical/biochemical phenotype-genotype correlation, difference in ethnic and subunit mutations still have certain characteristics.