medwireNews: Established genetic risk factors for adult-onset Graves’ disease apply equally in patients with a diagnosis in childhood, say researchers.
However, they also show that having more risk alleles for some of these variants may be associated with an earlier onset age.
Aleksander Kuś (Medical University of Warsaw, Poland) and co-researchers analysed 40 established and suggested Graves’ disease risk variants, identifying six for which the allele frequencies were significantly different in 179 patients with paediatric-onset Graves’ disease (diagnosed at ≤18 years) compared with in 1054 healthy control participants.
These same six variants were significantly associated with Graves’ disease among 1088 patients diagnosed in adulthood, as were an additional four variants. There was, however, no significant difference in the allele frequencies between patients with childhood- and adulthood-onset Graves’ disease, the researchers report in Clinical Endocrinology.
But they stress that they only assessed previously identified genetic variants, and that “there well may be variants specifically associated with” a paediatric-onset age. Identifying such variants would require a genome-wide association study in an “appropriately large cohort” of patients with paediatric-onset Graves’ disease.
The six variants associated with Graves’ disease irrespective of onset age were in the genes HCP5, TNF, TSHR, PTPN22, MAGI3 and CTLA4. The researchers observe that their study confirms a previous report of the association of CTLA4 with paediatric-onset Graves’ disease.
Of note, although the allele frequency of HCP5 did not differ between paediatric- and adult-onset patients, it was associated with onset age per se, with each additional C allele at the rs3094228 single nucleotide polymorphism associated with a significantly younger onset age.
There were also nonsignificant associations between onset age and variants in the PRICKLE1, SCGB3A2, RNASET2, MAGI3 and PTPN22 genes. However, Kuś and team stress that some of these nominal associations may represent false-positive findings.
They also point out that their findings may apply only to Caucasian patients, as only White participants were recruited to this study, and that their analysis was underpowered to detect variants with small or moderate effects.
By Eleanor McDermid
Clin Endocrinol 2018; doi:10.1111/cen.13887
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