Maple syrup urine disease (MSUD) is an autosomal recessive genetic disease and an inherited autosomal recessive trait. It is characterised by a deficiency of an enzyme complex, resulting in an excess of branched-chain amino acids (BCAAs), which are toxic to the nervous system. Our four cases generally presented with lethargy and poor feeding weeks after birth. They were all treated for sepsis until the laboratory results showed high levels of BCAAs, which indicated MSUD. Genetic analysis showed that the four cases were homozygous for the DBT gene mutation c.1196C>G (p.S399C), a possible founder mutation. All of our cases were managed accordingly, with regular monitoring of the BCAA levels. Dietary support, with infant formulas free of BCAAs, was provided to all four cases with regular follow-up at the paediatric genetic clinic. All cases had spastic diplegic and developmental delays.

Ornithine transcarbamylase (OTC) deficiency (OTCD), the most common urea cycle disorder, is an X-linked genetic disorder due to complete or partial lack of the OTC enzyme. Its clinical presentation depends on the degree of enzyme deficiency and ranges from an acute neonatal metabolic crisis with a high mortality rate through to an asymptomatic adult. We present a case of a newborn baby boy who presented with poor feeding, vomiting, lethargy, and respiratory distress. Laboratory investigations revealed severe hyperammonaemia, hyperglutaminaemia, hyperalaninaemia, absence of citrulline, and marked orotic aciduria. Family screening confirmed the presence of an OTC disease-causing mutation in his mother. It was a heterozygous mutation, c.316G>A. p. Gly106Arg in exon 4.