Generalized hypotonia, and Abnormality of extrapyramidal motor function

Guanidinoacetate methyltransferase (GAMT) deficiency is a creatine deficiency syndrome characterized by global developmental delay/intellectual disability (DD/ID), prominent speech delay, autistic/hyperactive behavioral disorders, seizures, and various types of pyramidal and/or extra-pyramidal manifestations.

GUANIDINOACETATE METHYLTRANSFERASE DEFICIENCY Is also known as gamt deficiency|creatine deficiency syndrome due to gamt deficiency|guanidinoacetate methyltransferase deficiency

• Intellectual disability
• Seizures
• Global developmental delay
• Generalized hypotonia
• Ataxia

SOURCES: MESH ORPHANET OMIM MENDELIAN

• Global developmental delay
• Generalized hypotonia
• Ataxia
• Hyperreflexia
• Intellectual disability, severe

SOURCES: OMIM MENDELIAN

Alternating hemiplegia of childhood is a rare syndrome characterized by infantile onset of episodic hemi-or quadriplegia. Most cases are accompanied by dystonic posturing, choreoathetoid movements, abnormal ocular movements, developmental delay, and progressive cognitive impairment (summary by Heinzen et al., 2012).For discussion of genetic heterogeneity of alternating hemiplegia of childhood, see AHC1 (OMIM ).

• Intellectual disability
• Seizures
• Global developmental delay
• Generalized hypotonia
• Ataxia

SOURCES: OMIM MENDELIAN

Neuronal ceroid lipofuscinosis-13 is an autosomal recessive neurodegenerative disorder characterized by adult onset of progressive cognitive decline and motor dysfunction leading to dementia and often early death. Some patients develop seizures. Neurons show abnormal accumulation of autofluorescent material (summary by Smith et al., 2013).Adult-onset neuronal ceroid lipofuscinosis is sometimes referred to as Kufs disease.For a discussion of genetic heterogeneity of neuronal ceroid lipofuscinosis (CLN), see CLN1 (OMIM ).

CLN13 DISEASE Is also known as ceroid lipofuscinosis, neuronal, 13, kufs type

• Seizures
• Generalized hypotonia
• Ataxia
• Cognitive impairment
• Hyperreflexia

SOURCES: OMIM ORPHANET MENDELIAN

PARKINSON DISEASE 4, AUTOSOMAL DOMINANT; PARK4 Is also known as parkinson disease 4, autosomal dominant lewy body

• Generalized hypotonia
• Cognitive impairment
• Tremor
• Dementia
• Weight loss

SOURCES: OMIM MESH MENDELIAN

DEDSM is a neurodevelopmental disorder characterized by global developmental delay, variable intellectual disability, and early-onset seizures with a myoclonic component. Most patients have delayed motor development and show abnormal movements, including ataxia, dystonia, and tremor (summary by Hamdan et al., 2017).

• Intellectual disability
• Seizures
• Global developmental delay
• Short stature
• Generalized hypotonia

SOURCES: OMIM MENDELIAN

Mild non-BH4-deficient hyperphenylalaninemia (HPANBH4) is an autosomal recessive disorder characterized by increased serum phenylalanine usually detected by newborn screening and associated with highly variable neurologic defects, including movement abnormalities and intellectual disability. Laboratory analysis shows dopamine and serotonin deficiencies in the cerebrospinal fluid, and normal BH4 metabolism. Evidence suggests that treatment with neurotransmitter precursors can lead to clinical improvement or even prevent the neurologic defects if started in infancy (summary by Anikster et al., 2017).

HYPERPHENYLALANINEMIA DUE TO DNAJC12 DEFICIENCY Is also known as non-phenylketonuric non-bh4-deficiency hyperphenylalaninemia

• Intellectual disability
• Seizures
• Global developmental delay
• Generalized hypotonia
• Nystagmus

SOURCES: ORPHANET OMIM MENDELIAN

• Intellectual disability
• Global developmental delay
• Generalized hypotonia
• Hearing impairment
• Ataxia

SOURCES: OMIM MENDELIAN

Spinocerebellar ataxia type 2 (SCA2) is a subtype of type I autosomal dominant cerebellar ataxia (ADCA type I; see this term) characterized by truncal ataxia, dysarthria, slowed saccades and less commonly ophthalmoparesis and chorea.

SPINOCEREBELLAR ATAXIA TYPE 2 Is also known as sca2

• Generalized hypotonia
• Nystagmus
• Dysarthria
• Dystonia
• Hyporeflexia

SOURCES: ORPHANET MENDELIAN

Pontocerebellar hypoplasia (PCH) represents a heterogeneous group of disorders characterized by an abnormally small cerebellum and brainstem. PCH type 2 is characterized by progressive microcephaly from birth combined with extrapyramidal dyskinesia and chorea, epilepsy, and normal spinal cord findings (Barth, 1993).For a phenotypic description and a discussion of genetic heterogeneity of PCH, see PCH1 (OMIM ).

• Seizures
• Generalized hypotonia
• Microcephaly
• Spasticity
• Feeding difficulties

SOURCES: OMIM MENDELIAN