Sleep disorders in succinic semialdehyde dehydrogenase deficiency: a family report

Speech Motor Function and Auditory Perception in Succinic Semialdehyde Dehydrogenase Deficiency: Toward Pre-Supplementary Motor Area (SMA) and SMA-Proper Dysfunctions

This study reviews the fundamental roles of pre-supplementary motor area (SMA) and SMA-proper responsible for speech-motor functions and auditory perception in succinic semialdehyde dehydrogenase (SSADH) deficiency. We comprehensively searched the databases of PubMed, Google Scholar, and the electronic journals Springer, PreQuest, and Science Direct associated with keywords SSADHD, SMA, auditory perception, speech, and motor with AND operator. Transcranial magnetic stimulation emerged for assessing excitability/inhibitory M1 functions, but its role in pre-SMA and SMA proper dysfunction remains unknown. There was a lack of data on resting-state and task-based functional magnetic resonance imaging (MRI), with a focus on passive and active tasks for both speech and music, in terms of analysis of SMA-related cortex and its connections. Children with SSADH deficiency likely experience a dysfunction in connectivity between SMA portions with cortical and subcortical areas contributing to disabilities in speech-motor functions and auditory perception. Early diagnosis of auditory-motor disabilities in children with SSADH deficiency by neuroimaging techniques invites opportunities for utilizing sensory-motor integration as future interventional strategies.

The characterization of psychotic symptoms in succinic semialdehyde dehydrogenase deficiency: a review

Succinic semialdehyde dehydrogenase (SSADH) deficiency is an ultra-rare inborn error of metabolism that results in disrupted gamma-amino butyric acid (GABA) catabolism. In addition to developmental delay, intellectual disability, hypotonia, ataxia, and seizures, a variety of neuropsychiatric symptoms may occur, including psychosis. By highlighting all available and relevant case reports/series, this qualitative review seeks to characterize the prevalence, clinical manifestation, pathophysiology, and treatment of psychotic symptoms in this population. Psychosis occurs in a minority of SSADH-deficient individuals, and most commonly presents as auditory or visual hallucinations with an onset in adolescence or young adulthood. Although the pathophysiology underlying the development of psychosis in this context is not fully understood, it likely in part relates to increased GABA and/or gamma hydroxybutyric acid activity. Although antipsychotic medications should be used cautiously in SSADH deficiency, they may be effective at treating emergent psychotic symptoms.

Incidence and Geographic Distribution of Succinic Semialdehyde Dehydrogenase (SSADH) Deficiency

The incidence of succinic semialdehyde dehydrogenase (SSADH) deficiency, an autosomal recessive inherited disorder of GABA degradation, is unknown. Upon a recent diagnosis of a new family of affected fraternal twins from the Punjabi ethnic group of India, case ascertainment from the literature and our database was done to determine the number of confirmed cases along with their geographic distribution. The probands presented with global developmental delay, infantile onset epilepsy, and a persistent neurodevelopmental disorder upon diagnosis at 10 years of age with intellectual disability, expressive aphasia, and behavioral problems most prominent for hyperactivity. Gamma-hydroxybutyric aciduria and homozygous ALDH5A1 c.608C>T; p.Pro203Leu mutations were confirmed. Identification of all available individual cases with clinical details available including geographic or ethnic origin revealed 182 patients from 40 countries, with the largest number of patients reported from the USA (24%), Turkey (10%), China (7%), Saudi Arabia (6%), and Germany (5%). This study provides an accounting of all published cases of confirmed SSADH deficiency and provides data useful in planning further studies of this rare inborn error of metabolism.