scholarly journals Adult male patient with severe intellectual disability caused by a homozygous mutation in the HNMT gene

2020 ◽  
Vol 13 (12) ◽  
pp. e235972
Author(s):  
Willem M A Verhoeven ◽  
Jos I M Egger ◽  
Paddy K C Janssen ◽  
Arie van Haeringen

Histamine is involved in various physiological functions like sleep–wake cycle and stress regulation. The histamine N-methyltransferase (HNMT) enzyme is the only pathway for termination of histamine neurotransmission in the central nervous system. Experiments with HNMT knockout mice generated aggressive behaviours and dysregulation of sleep–wake cycles. Recently, seven members of two unrelated consanguineous families have been reported in whom two different missense HNMT mutations were identified. All showed severe intellectual disability, delayed speech development and mild regression from the age of 5 years without, however, any dysmorphisms or congenital abnormality. A diagnosis of mental retardation, autosomal recessive 51 was made. Here, we describe a severely mentally retarded adolescent male born from second cousins with a homozygous mutation in HNMT. His phenotypic profile comprised aggression, delayed speech, autism, sleep disturbances and gastro-intestinal problems. At early age, regression occurred. Treatment with hydroxyzine combined with a histamine-restricted diet resulted in significant general improvement.

Author(s):  
Arvid Nikolai Kildahl ◽  
Trine Lise Bakken ◽  
Espen Arnfinn Winther Matre ◽  
Jane Margrethe Askeland Hellerud ◽  
Maria Hagen Engebretsen ◽  
...  

2015 ◽  
Vol 88 (1) ◽  
pp. E1-E4 ◽  
Author(s):  
M. Srour ◽  
F. F. Hamdan ◽  
Z. Gan-Or ◽  
D. Labuda ◽  
C. Nassif ◽  
...  

2020 ◽  
Vol 8 ◽  
pp. 232470962095777 ◽  
Author(s):  
Maria Elena Romero-Ibarguengoitia ◽  
Consuelo Cantú-Reyna ◽  
Dalia Gutierrez-González ◽  
Héctor Cruz-Camino ◽  
Arnulfo González-Cantú ◽  
...  

The intellectual disability syndrome characterized by seizures and dysmorphic features was initially described in 2017 and was associated with genetic variants in the OTUD6B gene, identified by exome sequencing (ES) in a large cohort. This multisystem disorder primarily affects the central nervous system, the gastrointestinal, and the skeletal systems. In this article, we describe the first Mexican patient diagnosed by ES. The homozygous c.433C>T (p.Arg145*) variant of the OTUD6B gene confirmed this intellectual disability syndrome. In addition to seizures and other more frequently reported manifestations of this condition, this is the third patient with associated hypothyroidism and hypogammaglobulinemia, underscoring the value of screening for these conditions in other patients. The current challenge with this patient is to ensure medical management of his seizures and provide him with a better quality of life. The possibilities of additional therapeutic approaches may increase by understanding the physiopathology of the involved pathways.


2013 ◽  
Vol 68 (3) ◽  
pp. 191-193 ◽  
Author(s):  
Joep de Ligt ◽  
Marjolein H. Willemsen ◽  
Bregje W. M. van Bon ◽  
Tjitske Kleefstra ◽  
Helger G. Yntema ◽  
...  

2001 ◽  
Vol 45 (5) ◽  
pp. 407-415 ◽  
Author(s):  
C. Sheard ◽  
J. Clegg ◽  
P. Standen ◽  
J. Cromby

1992 ◽  
Vol 36 (3) ◽  
pp. 318-327 ◽  
Author(s):  
Carolyn Grbich ◽  
Stewart Sykes

The area of severe intellectual disability has received little attention in Australian research. This Victorian study examined the issue of access to curricula in post primary school and special school placements for a group of students with severe intellectual disability. Results from the investigation indicated: that parents were generally dissatisfied with the lack of choice available regarding educational placements and the lack of opportunity for them to contribute in a supportive manner to their daughter's/son's schooling: that teachers in post primary schools reported an urgent need for special training or for specialised staff to assist them with curricular modification: and that the female students in this group experienced disadvantage in several curricular areas.


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