Phelan McDermid syndrome is a genetic and neurodevelopmental
condition caused by deletion of chromosome 22q13, by loss of
genetic material from the terminal end of chromosome 22 [1]. The
vast majority of affected patients present intellectual disability,
with an important impact on learning and language [2]. They
may also suffer from muscle pathology, like hypotonia and visual
defects. Likewise, they suffer neuropsychiatric issues as seizures
and behavioural alterations, as well as autism spectrum disorder
features [3]. Atypical bipolar disorder has been described in
these patients too [3]. Although the deletion can sometimes be
detected by high resolution chromosomal analysis, fluorescent in
situ hybridization (FISH) or comparative genomic hybridization
(CGH) is recommended to confirm the diagnosis [2,4]. There is no
aetiological treatment for this syndrome. Treatment is based on comorbid
pathologies and symptomatic management, although new
treatments are being studied [4].
A 15-year-old male was brought to the emergency room
and later was admitted into the Psychiatry Adolescent Unit due
to aggressive behaviour. The patient had been diagnosed with
intellectual disability since childhood. Also, language development
alterations and features had been detected. After presenting several
episodes of psychomotor agitation as well as panic episodes,
while he was suffering from several urinary and fungal infections,
complete organic screening was performed, including a genetic
study. Fluorescent in situ hybridization (FISH) showed a SHANK3
mutation in chromosome 22, a result compatible with Phelan
McDermid syndrome, diagnosis that was established. The patient’s
phenotype was compatible with this syndrome.
One month later, the patient presented several episodes
of anxiety without any trigger. Psychomotor restlessness and
escalating physical aggression toward objects at home appeared,
while he became increasingly expansive and irritable. Sometimes
he presented unmotivated laughter and soliloquies. Sleep
disturbances were significant as well, including decreased need
for sleep. Progressively greater difficulties to stay calm at home
appeared and the patient was admitted into the Psychiatry Unit.
After the young person was evaluated and explored, the diagnosis
of mania episode was established and the patient was initiated
on Quetiapine and Valproic Acid, which lead to a significant
improvement.
a) Studies to detect genetic disorders as Phelan McDermid
syndrome should be arranged in patients suffering from severe
psychiatric disturbances, especially if they have dysmorphic
features.
b) Psychiatric co-morbidity may be present in patients affected
with genetic disorders as Phelan McDermid syndrome and this
co-morbidity includes severe psychiatric features as mania and
psychotic symptoms.