Intellectual disability, and Distal sensory impairment

HSN2C is an autosomal recessive disorder characterized by onset in the first decade of progressive distal sensory loss leading to ulceration and amputation of the fingers and toes. Affected individuals also develop distal muscle weakness, primarily affecting the lower limbs (summary by Riviere et al., 2011).For a discussion of genetic heterogeneity of HSN, see HSAN1 (OMIM ).

• Global developmental delay
• Short stature
• Muscle weakness
• Peripheral neuropathy
• Areflexia

SOURCES: ORPHANET OMIM MENDELIAN

Autosomal dominant Charcot-Marie-Tooth disease, type 2K (CMT2K) is an axonal CMT peripheral sensorimotor polyneuropathy.

AUTOSOMAL DOMINANT CHARCOT-MARIE-TOOTH DISEASE TYPE 2K Is also known as cmt2k

• Motor delay
• Skeletal muscle atrophy
• Gait disturbance
• Arrhythmia
• Proximal muscle weakness

SOURCES: ORPHANET MENDELIAN

CHARCOT-MARIE-TOOTH DISEASE TYPE 1A Is also known as cmt1a|microduplication 17p12|charcot-marie-tooth neuropathy, type 1f

• Intellectual disability
• Generalized hypotonia
• Muscle weakness
• Motor delay
• Peripheral neuropathy

SOURCES: OMIM ORPHANET MENDELIAN

X-linked Charcot-Marie-Tooth disease type 4 is a rare, genetic, axonal, peripheral sensorimotor neuropathy characterized by an X-linked recessive inheritance pattern and the neonatal- to early childhood-onset of severe, slowly progressive, distal muscle weakness and atrophy (in particular of the peroneal group), as well as sensory impairment (with the lower extremities being more affected than the upper extremities), pes cavus, areflexia and hammertoes. Sensorineural hearing loss and cognitive impairment may also be associated. Females are asymptomatic and do not display the phenotype.

X-LINKED CHARCOT-MARIE-TOOTH DISEASE TYPE 4 Is also known as neuropathy, axonal motor-sensory, with deafness and mental retardation|charcot-marie-tooth disease with deafness and mental retardation|cowchock syndrome|nadmr|cmt4x|namsd|charcot-marie-tooth disease, x-linked recessive, 4|cmtx4

• Intellectual disability
• Global developmental delay
• Hearing impairment
• Scoliosis
• Ataxia

SOURCES: ORPHANET OMIM MENDELIAN

Charcot-Marie-Tooth disease type 4B3 (CMT4B3) is a subtype of Charcot-Marie-Tooth type 4 characterized by a childhood onset of slowly progressing, demyelinating sensorimotor neuropathy, focally folded myelin sheaths in nerve biopsy, reduced nerve conduction velocities (less than 38 m/s), and the typical CMT phenotype (i.e. distal muscle weakness and atrophy, and sensory loss).

CHARCOT-MARIE-TOOTH DISEASE TYPE 4B3 Is also known as charcot-marie-tooth disease with focally folded myelin|cmt4b3

• Intellectual disability
• Microcephaly
• Scoliosis
• Ataxia
• Strabismus

SOURCES: OMIM ORPHANET MENDELIAN

Autosomal recessive spinocerebellar ataxia-21 is a neurologic disorder characterized by onset of cerebellar ataxia associated with cerebellar atrophy in early childhood. Affected individuals also have recurrent episodes of liver failure in the first decade, resulting in chronic liver fibrosis, as well as later onset of a peripheral neuropathy. Mild learning disabilities may also occur (summary by Schmidt et al., 2015).

ACUTE INFANTILE LIVER FAILURE-CEREBELLAR ATAXIA-PERIPHERAL SENSORY MOTOR NEUROPATHY SYNDROME Is also known as spinocerebellar ataxia, autosomal recessive 21, with hepatopathy|autosomal recessive spinocerebellar ataxia type 21|scar21

• Intellectual disability
• Global developmental delay
• Ataxia
• Muscle weakness
• Spasticity

SOURCES: ORPHANET OMIM MENDELIAN

Ataxia-oculomotor apraxia syndrome is an early-onset autosomal recessive cerebellar ataxia with peripheral axonal neuropathy, oculomotor apraxia (defined as the limitation of ocular movements on command), and hypoalbuminemia (Moreira et al., 2001). Genetic Heterogeneity of Ataxia-Oculomotor ApraxiaSee also AOA2 (OMIM ), caused by mutation in the SETX gene (OMIM ) on chromosome 9q34; AOA3 (OMIM ), caused by mutation in the PIK3R5 gene (OMIM ) on chromosome 17p; and AOA4 (OMIM ), caused by mutation in the PNKP gene (OMIM ) on chromosome 19q13.

ATAXIA, EARLY-ONSET, WITH OCULOMOTOR APRAXIA AND HYPOALBUMINEMIA; EAOH Is also known as eoca-ha|aoa|ataxia-oculomotor apraxia syndrome|ataxia-oculomotor apraxia 1|aoa1|cerebellar ataxia, early-onset, with hypoalbuminemia|ataxia-telangiectasia-like syndrome

• Intellectual disability
• Scoliosis
• Ataxia
• Nystagmus
• Muscle weakness

SOURCES: OMIM MENDELIAN

Spinocerebellar ataxia with axonal neuropathy type 1 is a rare, genetic neurological disorder characterized by a late childhood onset of slowly progressive cerebellar ataxia. Initial manifestations include weakness and atrophy of distal limb muscles, areflexia and loss of pain, vibration and touch sensations in upper and lower extremities. Gaze nystagmus, cerebellar dysarthria, peripheral neuropathy, stepagge gait and pes cavus develop as disease progresses. Cerebellar atrophy (especially of the vermis) is present in all affected individuals. Additional reported manifestations include seizures, mild brain atrophy, mild hypercholesterolemia and borderline hypoalbuminemia.

SPINOCEREBELLAR ATAXIA WITH AXONAL NEUROPATHY TYPE 1 Is also known as scan1

• Intellectual disability
• Seizures
• Ataxia
• Nystagmus
• Neoplasm

SOURCES: OMIM MESH ORPHANET MENDELIAN

Yuan-Harel-Lupski syndrome is a complex neurodevelopmental disorder characterized by global developmental delay and early-onset peripheral neuropathy. The disorder comprises features of both demyelinating Charcot-Marie-Tooth disease type 1A (CMT1A ), which results from duplication of the PMP22 gene on 17p12, and Potocki-Lupski syndrome (PTLS ), which results from duplication of a slightly proximal region on 17p11.2 that includes the RAI1 gene. These 2 loci are about 2.5 Mb apart. The resultant YUHAL phenotype may be more severe in comparison to the individual contributions of each gene, with particularly early onset of peripheral neuropathy and features of both central and peripheral nervous system involvement (summary by Yuan et al., 2015).

PMP22-RAI1 CONTIGUOUS GENE DUPLICATION SYNDROME Is also known as trisomy 17p11.2-p12|dup(17)(p11.2p12)|trisomy 17p11.2p12|yuan-harel-lupski syndrome|17p11.2p12 microduplication syndrome

• Intellectual disability
• Global developmental delay
• Generalized hypotonia
• Failure to thrive
• Strabismus

SOURCES: OMIM ORPHANET MENDELIAN

Autosomal recessive spastic paraplegia type 55 (SPG 55) is a rare, complex type of hereditary spastic paraplegia characterized by childhood onset of progressive spastic paraplegia associated with optic atrophy (with reduced visual acuity and central scotoma), ophthalmoplegia, reduced upper-extremity strength and dexterity, muscular atrophy in the lower extremities, and sensorimotor neuropathy. SPG55 is caused by mutations in the C12ORF65 gene (12q24.31) encoding probable peptide chain release factor C12orf65, mitochondrial.

AUTOSOMAL RECESSIVE SPASTIC PARAPLEGIA TYPE 55 Is also known as spg55

• Intellectual disability
• Global developmental delay
• Nystagmus
• Strabismus
• Muscle weakness

SOURCES: ORPHANET OMIM MENDELIAN