<unk>  (OS), also known as Au–Kline syndrome (AKS), is a very rare autosomal dominant genetic condition characterised by congenital hydronephrosis, low muscle tone, heart defects, intellectual disability and characteristic facial features. Those affected often have neurological and skeletal abnormalities, as well as frequent urinary tract infections. Language and walking are usually delayed. Facial features include prominent, downturned ears, an open, downturned mouth and drooping eyelids (ptosis). The syndrome is caused by mutations in the HNRNPK gene, which codes for heterogeneous nuclear ribonucleoprotein K. This protein is involved in the process of DNA transcription and translation into proteins. A mutation in this gene impairs DNA transcription, disrupting some developmental processes. As an autosomal dominant disorder, only one faulty copy of the gene is required for the condition to occur. The syndrome is typically diagnosed based on the physical symptoms and then confirmed by genetic testing. Treatment has centred around the symptoms. Sign language and assistive language technology can aid communication. The prognosis is not yet fully known, due to the lack of patients in literature, however most of the patients have at least lived through childhood. The urinary system defects have been the most significant contributors to mortality. , 26 individuals worldwide were known to be affected. The syndrome was first described in 1997 by Nobuhiko<unk>  et al., and the gene responsible was first identified in 2015 by Ping-Yee Billie Au, Antonie D. Kline et al. In 2019,<unk>  proposed that Au–Kline syndrome and<unk>  were synonymous.
Okamoto syndrome
Yushō disease
Sanjad-Sakati syndrome
Satoyoshi syndrome
Mungan syndrome
Pashayan syndrome
Nakajo syndrome
Abruzzo–Erickson syndrome