Generalized hypotonia, and Hypertelorism

X-linked mental retardation-19 (MRX19) is a nonsyndromic form of mild to moderate mental retardation. Carrier females may be mildly affected. Mutation in the RPS6KA3 gene also causes Coffin-Lowry syndrome (CLS ), a mental retardation syndrome with dysmorphic facial features and skeletal anomalies. Some patients with RPS6KA3 mutations have an intermediate phenotype with mental retardation and only mild anomalies reminiscent of CLS. These individuals have mutations resulting in some residual protein function, which likely explains the milder phenotype (summary by Field et al., 2006).

• Intellectual disability
• Short stature
• Generalized hypotonia
• Scoliosis
• Hypertelorism

SOURCES: OMIM MESH MENDELIAN

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

SOURCES: OMIM MENDELIAN

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

SOURCES: OMIM MENDELIAN

IECEE1 is a neurodevelopmental disorder characterized by delayed psychomotor development apparent in infancy and resulting in severe to profound intellectual disability with poor or absent speech. Most patients never achieve independent walking. Patients typically have onset of refractory multifocal seizures between the first weeks and years of life, and some may show developmental regression. Additional features, such as hypotonia and cortical visual impairment, are more variable (summary by Myers et al., 2017). Genetic Heterogeneity of Infantile or Early Childhood Epileptic EncephalopathySee also IECEE2 (OMIM ), caused by mutation in the GABRB2 gene (OMIM ) on chromosome 5q34, and IECEE3 (OMIM ), caused by mutation in the ATP6V1A gene (OMIM ) on chromosome 3q13.

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

SOURCES: OMIM MENDELIAN

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

SOURCES: OMIM MENDELIAN

The peroxisomal biogenesis disorder (PBD) Zellweger syndrome (ZS) is an autosomal recessive multiple congenital anomaly syndrome. 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 4 (CG4, equivalent to CG6 and CGC) have mutations in the PEX6 gene. For information on the history of PBD complementation groups, see {214100}.

• Seizures
• Generalized hypotonia
• Hypertelorism
• Depressed nasal bridge
• Epicanthus

SOURCES: OMIM MESH MENDELIAN

Intellectual developmental disorder with neuropsychiatric features is an autosomal recessive disorder characterized by moderate intellectual disability, relatively mild seizures, and neuropsychiatric abnormalities, such as anxiety, obsessive-compulsive behavior, and autistic features. Mild facial dysmorphic features may also be present (summary by Srour et al., 2017).

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

SOURCES: OMIM MENDELIAN

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

SOURCES: OMIM MENDELIAN

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

SOURCES: OMIM MENDELIAN

Although the phenotypic spectrum and severity of FG syndrome is wide, the cardinal features include congenital hypotonia, delayed speech development, relative macrocephaly, dysmorphic facies, and anal anomalies or severe constipation (Unger et al., 2007).For a general phenotypic description and a discussion of genetic heterogeneity of FG syndrome, see FGS1 (OMIM ).

• Intellectual disability
• Seizures
• Generalized hypotonia
• Hypertelorism
• Failure to thrive

SOURCES: OMIM MENDELIAN