Two previously described mutations have been identified in the proband and confirmed in the parents
(Table 1). The first mutation, carried by the father, is the nonsense mutation c.78GNA (p.Trp26X) in exon 1.
This mutation was initially identified in combination with the missense mutation p.Arg178Leu in a patient
with infantile TSD of unspecified descent (Triggs-Raine et al., 1991). It was also described in homozygosity
in two Arab patients (Drucker and Navon, 1993; Haghighi et al., 2011). This mutation does not result in
any functional protein and therefore would not be expected to contribute to the residual Hex A activity
found in our patient