Transaldolase deficiency: A new case expands the phenotypic spectrum

Transaldolase (TALDO) deficiency has various clinical manifestations including liver dysfunction, hepatosplenomegaly, anemia, thrombocytopenia, and dysmorphic features. We report a case presenting prenatally with hyperechogenic bowel and intrauterine growth restriction. The infant was born small for gestational age, with cutis laxa and hypertrichosis. Postnatally, meconium plug was identified, complicated with intestinal obstruction necessitating laparotomy, partial resection of the intestine, and ileostomy. Liver biopsy revealed cholangiolar proliferation and portal fibrosis. He also suffered from persistent congenital thrombocytopenia requiring platelet transfusions and severe hypothyroidism with normal anatomical and structural gland responding only to the combination of T3 and T4 treatment. Neurologically, severe hypotonia and anisocoria were noted at the age of 2 months. Brain MRI was normal. Shortly after the abdominal surgery, a rapid liver failure ensued, which eventually led to his death. Specific metabolic tests ruled out glycosylation disorders, yet urine analysis using 1H NMR showed accumulation of sedoheptulose which was previously described in patients with transaldolase deficiency. Sequencing of the gene-encoding transaldolase (TALDO1) revealed a homozygous stop mutation c.669C>G; p.Tyr223*. In conclusion, we present an infant with a novel homozygous mutation in TALDO1, causing TALDO deficiency, and extend the clinical characteristics of this rare syndrome.