The neuronal ceroid lipofuscinoses are a group of inherited neurodegenerative disorders usually presenting in childhood, often known together as Batten Disease. Inheritance of two pathogenic alleles in the CLN2 gene causes a deficiency of the lysosomal enzyme, TPP1.CLN2 disease commonly presents with epilepsy between the ages of two and four years on a background of developmental delay which predominantly affects expressive speech. Brineura, an enzyme replacement therapy, was granted a Marketing Authorisation by the EMA and FDA in 2017, and approved byNICE and NHS England in November 2019[1]. A pivotal multinational clinical trial had demonstrated that this treatment preventedthe expected decline of clinical disease severity scores compared with untreated historical controls[2]. Going forward, comparison of disease milestones in treated patients with untreated patients cared for within the UK NHS will be essential in the evaluation of this and other novel therapies. This study was performed in order to begin to fill a knowledge gap.

The Evelina London Batten service has been taking national referrals since 2003. Referral patterns have varied over the years as the Batten Disease Family Association (BDFA) and their capacity to provide information and support for families has grown and other UK centres have developed expertise.

Clinical records of 45 patients with a confirmed diagnosis of CLN2 disease were reviewed and data extracted. Some patients became known to the author through participation in an early natural history study funded by the BDFA and the available data is patchy in some. In 25 patients, results of diagnostic genetic testing was available. The children were born between 1993 and 2015 and (in those 22 children in whom the date of diagnosis is known) diagnosed between 2004 and 2017.