Au-Kline syndrome with a novel variant in a girl presenting with heat intolerance in the summer: A case report and literature review

Background

Au-Kline syndrome (AKS) is characterized by moderate-to-severe intellectual disability, hypotonia, and distinctive characteristic facies. Other features, such as cardiac malformations, feeding difficulties, hydronephrosis, high pain tolerance, recurrent fever, abnormal sweating, and heat intolerance, have also been reported. However, our understanding of the heat tolerance of AKS remains limited.

Objective

We present a rare case of AKS in a 3-year old girl who presented with poor oral intake during the summer due to heat intolerance. Furthermore, we conducted a detailed review of AKS and investigated the extent to which heat intolerance was reported in patients with AKS.

Methods

To evaluate the “heat intolerance” in patients with HNRNPK variants, the literature in English was reviewed for cases reported as patients with HNRNPK variants by searching the PubMed database.

Results

A total of 456 articles were identified. We thoroughly reviewed the abstracts and selected articles describing cases with variants in HNRNPK, including two original articles, eight clinical case reports, and two letters to the editor. The cohort consisted of 23 male and 23 female patients with HNRNPK variants. Seventeen patients harbored missense variants, 27 harbored a truncating variant, and two harbored an intron variant. All variants in all the cases were de novo. In this review, we found no reported cases of heat intolerance.

Conclusion

We identified a novel HNRNPK variant of AKS associated with heat intolerance symptoms caused by abnormal sweating. Whether heat intolerance in AKS is extremely rare or underreported remains unclear, and further investigation is required.