Generalized hypotonia, and Micrognathia

SLC35A3-CDG is a form of congenital disorders of N-linked glycosylation characterized by distal arthrogryposis (mild flexion contractures of the fingers, deviation of the distal phalanges, swan-neck deformity), retromicrognathia, general muscle hypotonia, delayed psychomotor development, autism spectrum disorder (speech delay, abnormal use of speech, difficulties in initiating, understanding and maintaining social interaction, limited non-verbal communication and repetitive behavior), seizures, microcephaly and mild to moderate intellectual disability that becomes apparent with age. The disease is caused by mutations in the gene SLC35A3 (1p21).

AUTISM SPECTRUM DISORDER-EPILEPSY-ARTHROGRYPOSIS SYNDROME Is also known as slc35a3-cdg

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

SOURCES: OMIM ORPHANET MENDELIAN

Lethal congenital contracture syndrome-7, an axoglial form of arthrogryposis multiplex congenita, is characterized by congenital distal joint contractures, polyhydramnios, reduced fetal movements, and severe motor paralysis leading to death early in the neonatal period (Laquerriere et al., 2014).For a general phenotypic description and a discussion of genetic heterogeneity of lethal congenital contracture syndrome, see LCCS1 (OMIM ).

• Generalized hypotonia
• Micrognathia
• Cleft palate
• Flexion contracture
• Areflexia

SOURCES: OMIM MENDELIAN

• Generalized hypotonia
• Hearing impairment
• Micrognathia
• Sensorineural hearing impairment
• Cataract

SOURCES: OMIM MENDELIAN

Galloway-Mowat syndrome is a renal-neurologic disease characterized by early-onset nephrotic syndrome associated with microcephaly, gyral abnormalities, and delayed psychomotor development. Most patients have dysmorphic facial features, often including hypertelorism, ear abnormalities, and micrognathia. Other features, such as arachnodactyly and visual impairment, are more variable. Most patients die in the first years of life (summary by Braun et al., 2017).For a general phenotypic description and a discussion of genetic heterogeneity of GAMOS, see GAMOS1 (OMIM ).

• Seizures
• Global developmental delay
• Short stature
• Generalized hypotonia
• Microcephaly

SOURCES: OMIM MENDELIAN

Centronuclear myopathy-5 is an autosomal recessive congenital myopathy characterized by severe neonatal hypotonia with respiratory insufficiency and difficulty feeding. Some patients die in infancy, and some develop dilated cardiomyopathy. Children show severely delayed motor development (summary by Agrawal et al., 2014).For a discussion of genetic heterogeneity of centronuclear myopathy, see CNM1 (OMIM ).

• Generalized hypotonia
• Micrognathia
• Flexion contracture
• High palate
• Motor delay

SOURCES: OMIM MENDELIAN

Lethal left ventricular non-compaction-seizures-hypotonia-cataract-developmental delay syndrome is rare, genetic, neurometabolic disease characterized by global developmental delay, severe hypotonia, seizures, cataracts, cardiomyopathy (including left or bi-ventricular hypertrophy, dilated cardiomyopathy) and left ventricular non-compaction, typically resulting in infantile or early-childhood death. Patients usually present metabolic lactic acidosis, failure to thrive, head lag, respiratory problems and decrease in respiratory chain complex activity. Highly variable cerebral abnormalities have been reported and include microcephaly, prominent extra-axial cerebrospinal fluid spaces, diffuse neuronal loss and cortical/white matter gliosis.

• Seizures
• Global developmental delay
• Generalized hypotonia
• Microcephaly
• Failure to thrive

SOURCES: OMIM ORPHANET MENDELIAN

Fast-channel congenital myasthenic syndrome (FCCMS) is a disorder of the postsynaptic neuromuscular junction (NMJ) characterized by early-onset progressive muscle weakness. The disorder results from kinetic abnormalities of the acetylcholine receptor channel, specifically from abnormally brief opening and activity of the channel, with a rapid decay in endplate current and a failure to reach the threshold for depolarization. Treatment with pyridostigmine or amifampridine may be helpful; quinine, quinidine, and fluoxetine should be avoided (summary by Sine et al., 2003 and Engel et al., 2015).For a discussion of genetic heterogeneity of CMS, see CMS1A (OMIM ).

• Generalized hypotonia
• Micrognathia
• Muscle weakness
• Ptosis
• Flexion contracture

SOURCES: OMIM MENDELIAN

Early infantile epileptic encephalopathy-64 is a neurodevelopmental disorder characterized by onset of seizures usually in the first year of life and associated with intellectual disability, poor motor development, and poor or absent speech. Additional features include hypotonia, abnormal movements, and nonspecific dysmorphic features. The severity is variable: some patients are unable to speak, walk, or interact with others as late as the teenage years, whereas others may have some comprehension (summary by Straub et al., 2018).For a general phenotypic description and a discussion of genetic heterogeneity of EIEE, see EIEE1 (OMIM ).

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

SOURCES: OMIM MENDELIAN

Zellweger syndrome (ZS) is an autosomal recessive multiple congenital anomaly syndrome resulting from disordered peroxisome biogenesis. Affected children present in the newborn period with profound hypotonia, seizures, and inability to feed. Characteristic craniofacial anomalies, eye abnormalities, neuronal migration defects, hepatomegaly, and chondrodysplasia punctata are present. Children with this condition do not show any significant development and usually die in the first year of life (summary by Steinberg et al., 2006).For a complete phenotypic description and a discussion of genetic heterogeneity of Zellweger syndrome, see {214100}.Individuals with PBDs of complementation group K (CGK) have mutations in the PEX14 gene. For information on the history of PBD complementation groups, see {214100}.

• Seizures
• Generalized hypotonia
• Micrognathia
• Feeding difficulties
• Hepatomegaly

SOURCES: MESH OMIM MENDELIAN

CLASSIC MULTIMINICORE MYOPATHY Is also known as classic multiminicore disease|classic mmd

• Short stature
• Generalized hypotonia
• Scoliosis
• Failure to thrive
• High palate

SOURCES: ORPHANET MENDELIAN