Global developmental delay, and Respiratory failure

Combined oxidative phosphorylation deficiency-28 (COXPD28) is a complex autosomal recessive multisystem disorder associated with mitochondrial dysfunction. The phenotype is variable, but includes episodic metabolic decompensation beginning in infancy that can result in mild muscle weakness, cardiorespiratory insufficiency, developmental delay, or even death. Biochemical studies of patient tissues show variable mitochondrial defects, including decreased activities of respiratory chain enzymes (summary by Kishita et al., 2015).For a discussion of genetic heterogeneity of combined oxidative phosphorylation deficiency, see COXPD1 (OMIM ).

NEONATAL SEVERE CARDIOPULMONARY FAILURE DUE TO MITOCHONDRIAL METHYLATION DEFECT Is also known as combined oxidative phosphorylation defect type 28|coxpd28

• Global developmental delay
• Generalized hypotonia
• Muscle weakness
• Pain
• Hypertension

SOURCES: OMIM ORPHANET MENDELIAN

Multiple mitochondrial dysfunctions syndrome is a severe autosomal recessive disorder of systemic energy metabolism, resulting in weakness, respiratory failure, lack of neurologic development, lactic acidosis, and early death (summary by Seyda et al., 2001). Genetic Heterogeneity of Multiple Mitochondrial Dysfunctions SyndromeSee also MMDS2 (OMIM ), caused by mutation in the BOLA3 gene (OMIM ) on chromosome 2p13; MMDS3 (OMIM ), caused by mutation in the IBA57 gene (OMIM ) on chromosome 1q42; MMDS4 (OMIM ), caused by mutation in the ISCA2 gene (OMIM ) on chromosome 14q24; MMDS5 (OMIM ), caused by mutation in the ISCA1 gene (OMIM ) on chromosome 9q21; and MMDS6 (OMIM ), caused by mutation in the PMPCB gene (OMIM ) on chromosome 7q22.

MULTIPLE MITOCHONDRIAL DYSFUNCTIONS SYNDROME 1; MMDS1 Is also known as mmds

• Global developmental delay
• Generalized hypotonia
• Failure to thrive
• Muscle weakness
• Feeding difficulties

SOURCES: OMIM MENDELIAN

Pontocerebellar hypoplasia type 4 (PCH4) is a very rare form of PCH (see this term), characterized by prenatal onset of polyhydramnios and contractures followed by hypertonia, severe clonus, primary hypoventilation leading to an early postnatal death.

PONTOCEREBELLAR HYPOPLASIA TYPE 4 Is also known as fatal infantile encephalopathy with olivopontocerebellar hypoplasia|olivopontocerebellar hypoplasia|encephalopathy, fatal infantile, with olivopontocerebellar hypoplasia|pch4

• Seizures
• Microcephaly
• Spasticity
• Flexion contracture
• Cerebellar atrophy

SOURCES: ORPHANET MESH OMIM MENDELIAN

Early-onset progressive encephalopathy with brain edema and/or leukoencephalopathy (PEBEL) is an autosomal recessive severe neurometabolic disorder characterized by rapidly progressive neurologic deterioration that is usually associated with a febrile illness. Affected infants tend to show normal early development followed by acute psychomotor regression with ataxia, hypotonia, respiratory insufficiency, and seizures, resulting in coma and death in the first years of life. Brain imaging shows multiple abnormalities, including brain edema and signal abnormalities in the cortical and subcortical regions (summary by Kremer et al., 2016).

• Seizures
• Global developmental delay
• Generalized hypotonia
• Ataxia
• Nystagmus

SOURCES: OMIM MENDELIAN

Severe neonatal-onset encephalopathy with microcephaly is a rare monogenic disease with epilepsy characterized by neonatal-onset encephalopathy, microcephaly, severe developmental delay or absent development, breathing abnormalities (including central hypoventilation and/or respiratory insufficiency), intractable seizures, abnormal muscle tone and involuntary movements. Early death is usual.

SEVERE NEONATAL-ONSET ENCEPHALOPATHY WITH MICROCEPHALY Is also known as severe congenital encephalopathy due to mecp2 mutation

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

SOURCES: ORPHANET MESH OMIM MENDELIAN

Pontocerebellar hypoplasia type 1C is a severe autosomal recessive neurodegenerative disorder characterized by severe muscle weakness and failure to thrive apparent in the first months of life. Affected infants showed delayed psychomotor development, often with visual and hearing impairment, and may die of respiratory failure. Brain imaging typically shows cerebellar hypoplasia, hypoplasia of the corpus callosum, and immature myelination (summary by Boczonadi et al., 2014).For a phenotypic description and a discussion of genetic heterogeneity of PCH, see PCH1A (OMIM ).

PONTOCEREBELLAR HYPOPLASIA, TYPE 1C; PCH1C Is also known as hypomyelination with spinal muscular atrophy and cerebellar hypoplasia

• Global developmental delay
• Hearing impairment
• Failure to thrive
• Muscle weakness
• Flexion contracture

SOURCES: OMIM MENDELIAN

Stress-induced childhood-onset neurodegeneration with variable ataxia and seizures (CONDSIAS) is an autosomal recessive neurodegenerative disorder with onset in the first years of life following normal early development. Patient have cyclic episodic deterioration in response to stress, such as infection or febrile illness. The severity is highly variable: some patients develop seizures early in life that are associated with loss of developmental milestones and early sudden death in childhood, whereas others present at a later age with muscle weakness, gait ataxia, impaired speech, more subtle clinical deterioration, and cognitive decline. Neurologic involvement includes gait ataxia, cerebellar signs associated with cerebellar atrophy, generalized brain atrophy, impaired intellectual development, hearing loss, and peripheral neuropathy (summary by Ghosh et al., 2018).

• Seizures
• Global developmental delay
• Hearing impairment
• Ataxia
• Nystagmus

SOURCES: OMIM MENDELIAN

Chronic Epstein-Barr virus infection syndrome is a rare infectious disease characterized by familial, primary, chronic Epstein-Barr virus infection which typically manifests with persistent mononucleosis-like signs and symptoms, in the absence of secondary immunodeficiency.

CHRONIC EPSTEIN-BARR VIRUS INFECTION SYNDROME Is also known as irf8 deficiency, autosomal recessive|epstein-barr virus, susceptibility to chronic infection by|immunodeficiency 32b, monocyte, dendritic cell, and natural killer cell deficiency, autosomal recessive|caebv syndrome|chronic ebv infection syndrome

• Global developmental delay
• Neoplasm
• Failure to thrive
• Anemia
• Hepatomegaly

SOURCES: ORPHANET OMIM MENDELIAN

Brain-lung-thyroid syndrome is a rare disorder characterized by congenital hypothyroidism (CH), infant respiratory distress syndrome (IRDS) and benign hereditary chorea (BHC; see these terms).

BRAIN-LUNG-THYROID SYNDROME Is also known as choreoathetosis-hypothyroidism-neonatal respiratory distress syndrome|brain-lung-thyroid syndrome

• Global developmental delay
• Generalized hypotonia
• Ataxia
• Muscular hypotonia
• Motor delay

SOURCES: OMIM MESH ORPHANET MENDELIAN

Hyperekplexia-4 is an autosomal recessive severe neurologic disorder apparent at birth. Affected infants have extreme hypertonia and appear stiff and rigid. They have little if any development, poor or absent visual contact, and no spontaneous movement, consistent with an encephalopathy. Some patients have early-onset refractory seizures, and many have inguinal or umbilical hernia. Most patients die in the first months of life due to respiratory failure or other complications (summary by Piard et al., 2018).For a general description and a discussion of genetic heterogeneity of hyperekplexia, see HKPX1 (OMIM ).

• Seizures
• Global developmental delay
• Flexion contracture
• High palate
• Hyperreflexia

SOURCES: OMIM MENDELIAN