Hearing impairment, and Generalized myoclonic seizures

Histidinemia is a rare metabolic disorder characterized by elevated histidine levels in blood, urine, and cerebrospinal fluid, generally with no clinical repercussions.

HISTIDINEMIA Is also known as his deficiency|histidinuria|histidase deficiency|hyperhistidinemia|hal deficiency|histidine ammonia-lyase deficiency

• Intellectual disability
• Sensorineural hearing impairment
• Wide nasal bridge
• Long philtrum
• Macrotia

SOURCES: ORPHANET OMIM MENDELIAN

Neonatal intractable myoclonus is a severe neurologic disorder characterized by the onset of intractable myoclonic seizures soon after birth. Affected infants have intermittent apnea, abnormal eye movements, pallor of the optic nerve, and lack of developmental progress. Brain imaging shows a progressive leukoencephalopathy. Some patients may die in infancy. There is phenotypic and biochemical evidence of mitochondrial dysfunction (summary by Duis et al., 2016).

• Seizures
• Generalized hypotonia
• Hearing impairment
• Microcephaly
• Nystagmus

SOURCES: OMIM MENDELIAN

Fiskerstrand type peripheral neuropathy is a slowly-progressive Refsum-like disorder associating signs of peripheral neuropathy with late-onset hearing loss, cataract and pigmentary retinopathy that become evident during the third decade of life.

POLYNEUROPATHY-HEARING LOSS-ATAXIA-RETINITIS PIGMENTOSA-CATARACT SYNDROME Is also known as peripheral neuropathy, fiskerstrand type|pharc syndrome

• Seizures
• Hearing impairment
• Ataxia
• Nystagmus
• Sensorineural hearing impairment

SOURCES: MESH OMIM ORPHANET MENDELIAN

Spinal muscular atrophy-progressive myoclonic epilepsy syndrome is characterized by hereditary myoclonus and progressive distal muscular atrophy. Less than 10 cases have been reported. Treatment with clonazepam results in complete and lasting improvement of the myoclonus.

SPINAL MUSCULAR ATROPHY-PROGRESSIVE MYOCLONIC EPILEPSY SYNDROME Is also known as hereditary myoclonus-progressive distal muscular atrophy syndrome|jankovic-rivera syndrome|myoclonus, hereditary, with progressive distal muscular atrophy

• Seizures
• Generalized hypotonia
• Hearing impairment
• Scoliosis
• Sensorineural hearing impairment

SOURCES: ORPHANET MESH OMIM MENDELIAN

MGCA8 is an autosomal recessive metabolic disorder resulting in death in infancy. Features include hypotonia, abnormal movements, respiratory insufficiency with apneic episodes, and lack of developmental progress, often with seizures. Brain imaging is variable, but may show progressive cerebral atrophy. Laboratory studies show increased serum lactate and 3-methylglutaconic aciduria, suggesting a mitochondrial defect (summary by Mandel et al., 2016).For a phenotypic description and a discussion of genetic heterogeneity of 3-methylglutaconic aciduria, see MGCA type I (OMIM ).

• Seizures
• Generalized hypotonia
• Hearing impairment
• Microcephaly
• Growth delay

SOURCES: OMIM MENDELIAN

Combined oxidative phosphorylation defect type 14 is a rare mitochondrial disease due to a defect in mitochondrial protein synthesis characterized by neonatal or infancy-onset of seizures that are refractory to treatment, delayed or absent psychomotor development and lactic acidosis. Additional manifestations reported include poor feeding, failure to thrive, microcephaly, hypotonia, anemia and thrombocytopenia.

COMBINED OXIDATIVE PHOSPHORYLATION DEFECT TYPE 14 Is also known as coxpd14

• Seizures
• Global developmental delay
• Generalized hypotonia
• Hearing impairment
• Microcephaly

SOURCES: ORPHANET OMIM MENDELIAN

Permanent neonatal diabetes mellitus (PNDM) is a monogenic form of neonatal diabetes (NDM, see this term) characterized by persistent hyperglycemia within the first 12 months of life in general, requiring continuous insulin treatment.

PERMANENT NEONATAL DIABETES MELLITUS Is also known as monogenic diabetes of infancy|pndm

• Intellectual disability
• Global developmental delay
• Hearing impairment
• Ataxia
• Failure to thrive

SOURCES: ORPHANET MENDELIAN

Transient neonatal diabetes mellitus (TNDM) is a genetically heterogeneous form of neonatal diabetes (NDM, see this term) characterized by hyperglycemia presenting in the neonatal period that remits during infancy but recurs in later life in most patients.

TRANSIENT NEONATAL DIABETES MELLITUS Is also known as tndm3|tndm

• Intellectual disability
• Seizures
• Global developmental delay
• Hearing impairment
• Failure to thrive

SOURCES: ORPHANET OMIM MENDELIAN

Spastic paraplegia-severe developmental delay-epilepsy syndrome is a rare, genetic, complex spastic paraplegia disorder characterized by an infantile-onset of psychomotor developmental delay with severe intellectual disability and poor speech acquisition, associated with seizures (mostly myoclonic), muscular hypotonia which may be noted at birth, and slowly progressive spasticity in the lower limbs leading to severe gait disturbances. Ocular abnormalities and incontinence are commonly associated. Other symptoms may include verbal dyspraxia, hypogenitalism, macrocephaly and sensorineural hearing loss, as well as dystonic movements and ataxia with upper limb involvement.

SPASTIC PARAPLEGIA-SEVERE DEVELOPMENTAL DELAY-EPILEPSY SYNDROME Is also known as spastic paraplegia-psychomotor retardation-seizures syndrome|spprs syndrome

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

SOURCES: OMIM ORPHANET MENDELIAN

Spinocerebellar ataxia with epilepsy is a rare, mitochondrial DNA maintenance syndrome characterized by cerebellar ataxia, sensory peripheral neuropathy, myoclonus, epilepsy, progressive cognitive impairment, late-onset ptosis and external ophthalmoplegia. Liver failure may also occur, most often in association with the use of antiepileptic drug sodium valproate.

SPINOCEREBELLAR ATAXIA WITH EPILEPSY Is also known as mitochondrial spinocerebellar ataxia with epilepsy|mscae|sensory ataxic neuropathy with mitochondrial dna deletions, autosomal recessive|scae

• Seizures
• Hearing impairment
• Ataxia
• Nystagmus
• Sensorineural hearing impairment

SOURCES: OMIM ORPHANET MENDELIAN