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Language delay and attention deficit-hyperactivity disorder/cognitive impairment with or without cardiac arrhythmia(LDMLS2)

MedGen UID:
934645
Concept ID:
C4310678
Disease or Syndrome
Synonyms: LDMLS2; LODDER-MERLA SYNDROME, TYPE 2, WITH DEVELOPMENTAL DELAY AND WITH OR WITHOUT CARDIAC ARRHYTHMIA
 
Gene (location): GNB5 (15q21.2)
 
Monarch Initiative: MONDO:0014957
OMIM®: 617182

Disease characteristics

Excerpted from the GeneReview: GNB5-Related Neurodevelopmental Disorder
GNB5-related neurodevelopmental disorder (GNB5-NDD) is characterized by a spectrum of neurodevelopmental phenotypes that range from severe-to-profound intellectual disability (ID; 31/41 reported individuals), to mild-to-moderate ID (5/41), to normal intellect with severe language disorder (5/41, one extended family). A unique and specific feature of GNB5-NDD – regardless of neurodevelopmental phenotype – is nearly universal bradycardia caused by sinoatrial node dysfunction (sick sinus syndrome). Most individuals with severe and profound ID have a developmental and epileptic encephalopathy with focal seizures or epileptic spasms, as well as visual impairment (central or retinal) with nystagmus, difficulty feeding, and gastroesophageal reflux disease. The risk of early mortality is increased. [from GeneReviews]
Authors:
Gemma Poke  |  Lynette Grant Sadleir  |  Giuseppe Merla, et. al.   view full author information

Additional description

From OMIM
Lodder-Merla syndrome type 2 with developmental delay and with or without cardiac arrhythmia (LDMLS2) is an autosomal recessive neurodevelopmental disorder characterized by severe expressive and receptive language delay apparent from early childhood. Affected individuals have additional developmental or behavioral abnormalities, including attention deficit, hyperactivity, or mild intellectual disability. Some patients develop cardiac arrhythmias reminiscent of sick sinus syndrome (summary by Lodder et al., 2016 and Shamseldin et al., 2016). Genotype-Phenotype Correlation A direct correlation has been noted between the type of GNB5 variant and the severity of the related phenotype. Individuals with missense variants, both in homozygous or compound heterozygous states (LDMLS2), present with a less severe/moderate phenotype characterized mainly by sinus node dysfunction in combination with mild intellectual disabilities, whereas individuals homozygous for null alleles (LDMLS1) have severe ID, global developmental delay including early infantile developmental and epileptic encephalopathy, hypotonia, as well as sinus node dysfunction (Malerba et al., 2018).  http://www.omim.org/entry/617182

Clinical features

From HPO
Patent foramen ovale
MedGen UID:
8891
Concept ID:
C0016522
Congenital Abnormality
Failure of the foramen ovale to seal postnatally, leaving a potential conduit between the left and right cardiac atria.
Sick sinus syndrome
MedGen UID:
20749
Concept ID:
C0037052
Disease or Syndrome
An abnormality involving the generation of the action potential by the sinus node and is characterized by an atrial rate inappropriate for physiological requirements. Manifestations include severe sinus bradycardia, sinus pauses or arrest, sinus node exit block, chronic atrial tachyarrhythmias, alternating periods of atrial bradyarrhythmias and tachyarrhythmias, and inappropriate responses of heart rate during exercise or stress.
Bradycardia
MedGen UID:
140901
Concept ID:
C0428977
Finding
A slower than normal heart rate (in adults, slower than 60 beats per minute).
Gastroesophageal reflux
MedGen UID:
1368658
Concept ID:
C4317146
Finding
A condition in which the stomach contents leak backwards from the stomach into the esophagus through the lower esophageal sphincter.
Seizure
MedGen UID:
20693
Concept ID:
C0036572
Sign or Symptom
A seizure is an intermittent abnormality of nervous system physiology characterised by a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain.
Hyperactivity
MedGen UID:
98406
Concept ID:
C0424295
Finding
Hyperactivity is a condition characterized by constant and unusually high levels of activity, even in situations where it is deemed inappropriate.
Delayed speech and language development
MedGen UID:
105318
Concept ID:
C0454644
Finding
A degree of language development that is significantly below the norm for a child of a specified age.
Global developmental delay
MedGen UID:
107838
Concept ID:
C0557874
Finding
A delay in the achievement of motor or mental milestones in the domains of development of a child, including motor skills, speech and language, cognitive skills, and social and emotional skills. This term should only be used to describe children younger than five years of age.
Attention deficit hyperactivity disorder
MedGen UID:
220387
Concept ID:
C1263846
Mental or Behavioral Dysfunction
Attention-deficit/hyperactivity disorder (ADHD) is a behavioral disorder that typically begins in childhood and is characterized by a short attention span (inattention), an inability to be calm and stay still (hyperactivity), and poor impulse control (impulsivity). Some people with ADHD have problems with only inattention or with hyperactivity and impulsivity, but most have problems related to all three features.\n\nIn people with ADHD, the characteristic behaviors are frequent and severe enough to interfere with the activities of daily living such as school, work, and relationships with others. Because of an inability to stay focused on tasks, people with inattention may be easily distracted, forgetful, avoid tasks that require sustained attention, have difficulty organizing tasks, or frequently lose items.\n\nHyperactivity is usually shown by frequent movement. Individuals with this feature often fidget or tap their foot when seated, leave their seat when it is inappropriate to do so (such as in the classroom), or talk a lot and interrupt others.\n\nImpulsivity can result in hasty actions without thought for the consequences. Individuals with poor impulse control may have difficulty waiting for their turn, deferring to others, or considering their actions before acting.\n\nIn most affected individuals, ADHD continues throughout life, but in about one-third of individuals, signs and symptoms of ADHD go away by adulthood.\n\nMore than two-thirds of all individuals with ADHD have additional conditions, including insomnia, mood or anxiety disorders, learning disorders, or substance use disorders. Affected individuals may also have autism spectrum disorder, which is characterized by impaired communication and social interaction, or Tourette syndrome, which is a disorder characterized by repetitive and involuntary movements or noises called tics.
Motor delay
MedGen UID:
381392
Concept ID:
C1854301
Finding
A type of Developmental delay characterized by a delay in acquiring motor skills.
Absent speech
MedGen UID:
340737
Concept ID:
C1854882
Finding
Complete lack of development of speech and language abilities.
Poor fine motor coordination
MedGen UID:
356863
Concept ID:
C1867864
Finding
An abnormality of the ability (skills) to perform a precise movement of small muscles with the intent to perform a specific act. Fine motor skills are required to mediate movements of the wrists, hands, fingers, feet, and toes.
Intellectual disability
MedGen UID:
811461
Concept ID:
C3714756
Mental or Behavioral Dysfunction
Intellectual disability, previously referred to as mental retardation, is characterized by subnormal intellectual functioning that occurs during the developmental period. It is defined by an IQ score below 70.
Hypotonia
MedGen UID:
10133
Concept ID:
C0026827
Finding
Hypotonia is an abnormally low muscle tone (the amount of tension or resistance to movement in a muscle). Even when relaxed, muscles have a continuous and passive partial contraction which provides some resistance to passive stretching. Hypotonia thus manifests as diminished resistance to passive stretching. Hypotonia is not the same as muscle weakness, although the two conditions can co-exist.
Microcephaly
MedGen UID:
1644158
Concept ID:
C4551563
Finding
Head circumference below 2 standard deviations below the mean for age and gender.
Nystagmus
MedGen UID:
45166
Concept ID:
C0028738
Disease or Syndrome
Rhythmic, involuntary oscillations of one or both eyes related to abnormality in fixation, conjugate gaze, or vestibular mechanisms.

Professional guidelines

PubMed

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Recent clinical studies

Etiology

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Guasch E, Mont L
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Diagnosis

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Therapy

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Prognosis

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