patients 2 and 3 showed only the c.1448T4C (p.L483P)
mutation, which could be homozygous or hemizygous. Therefore,
the genotypes of their parents were studied and revealed that all were
heterozygous for the p.L483P (L444P) mutation, suggesting that
patients 2 and 3 were homozygous for the mutation. p.L483P
(L444P) is the most common mutant allele in the Thai
patients with GD studied, accounting for 60% of mutant alleles.
Notably, because conventional PCR method could not distinguish the
isolate p.L483P (L444P) mutation and the p.L483P (L444P) as a part
of a recombinant allele carrying additional pseudogene sequence
alterations, further evaluation by other techniques such as direct
sequencing to establish the presence or absence of a complex allele
should be considered.8,9 The p.L483P (L444P) mutation occurs with
significant frequencies in various populations, including 41% of
mutant alleles in the Japanese,6 and 2.84% in the Jewish.10 At the
age of death at 16 years in patient 2 and 12 years in patient 3, both
patients with homozygous p.L483P (L444P) did not show
primary neurological manifestations, and, therefore, were categorized
as type 1. A previously reported Thai patient with homozygous for the
p.L483P (L444P) mutation was described to have a ‘Norbottnian-like’