Beschreibung:
<jats:title>Abstract</jats:title>
<jats:sec id="j_jpem-2021-0165_abs_001">
<jats:title>Objectives</jats:title>
<jats:p>Hypomagnesemia 1, intestinal (HOMG1) is characterized by neurological symptoms that occur due to hypocalcemia and hypomagnesemia and caused by mutations in the <jats:italic>TRPM6</jats:italic>. Most of the identified variants in <jats:italic>TRPM6</jats:italic> lead to premature termination: nonsense, frameshift, deletion, and splice site mutations.</jats:p>
</jats:sec>
<jats:sec id="j_jpem-2021-0165_abs_002">
<jats:title>Case presentation</jats:title>
<jats:p>Herein, we report a 1.5 month-old case who presented with convulsion due to hypocalcemia and hypomagnesemia in the early infancy. Sequencing of <jats:italic>TRPM6</jats:italic> revealed a novel homozygous synonymous variant [c.2538G > A (p.Thr846Thr)] in the last codon of exon 19, which is most likely to affect the splicing. We report a novel homozygous synonymous variant in the <jats:italic>TRPM6</jats:italic> leading to HOMG1, expanding the mutational spectrum.</jats:p>
</jats:sec>
<jats:sec id="j_jpem-2021-0165_abs_003">
<jats:title>Conclusions</jats:title>
<jats:p>Synonymous mutations that were previously considered as harmless should be evaluated at the nucleotide level, keeping in mind that they may affect splicing and cause to the disease.</jats:p>
</jats:sec>