Hypertelorism, and Cerebellar hypoplasia

Lissencephaly syndrome, Norman-Roberts type is characterised by the association of lissencephaly type I with craniofacial anomalies (severe microcephaly, a low sloping forehead, a broad and prominent nasal bridge and widely set eyes) and postnatal growth retardation.

LISSENCEPHALY SYNDROME, NORMAN-ROBERTS TYPE Is also known as norman-roberts syndrome|lissencephaly syndrome, norman-roberts type|microlissencephaly type a

• Intellectual disability
• Seizures
• Generalized hypotonia
• Microcephaly
• Growth delay

SOURCES: ORPHANET OMIM MENDELIAN

GPIBD15 is an autosomal recessive disorder characterized by delayed psychomotor development, variable intellectual disability, hypotonia, early-onset seizures in most patients, and cerebellar atrophy, resulting in cerebellar signs including gait ataxia and dysarthria. The disorder is caused by a defect in glycosylphosphatidylinositol (GPI) biosynthesis (summary by Nguyen et al., 2017).For a discussion of genetic heterogeneity of GPI biosynthesis defects, see GPIBD1 (OMIM ).

GLYCOSYLPHOSPHATIDYLINOSITOL BIOSYNTHESIS DEFECT 15; GPIBD15 Is also known as developmental delay, epilepsy, cerebellar atrophy, and osteopenia

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

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

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

SOURCES: OMIM MENDELIAN

Autosomal recessive primary microcephaly-17 (MCPH17) is a severe neurologic disorder characterized by very small head circumference that is apparent at birth and worsens over time (up to -12 SD). Affected individuals have delayed psychomotor development, intellectual disability, spasticity, axial hypotonia, and dysmorphic features. Brain imaging shows a simplified gyral pattern; more severe cases have lissencephaly with hypoplasia of the brainstem and cerebellum (summary by Harding et al., 2016).For a phenotypic description and a discussion of genetic heterogeneity of primary microcephaly, see MCPH1 (OMIM ).

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

SOURCES: OMIM MENDELIAN

Intellectual disability-obesity-brain malformations-facial dysmorphism syndrome is a rare, syndromic intellectual disability primarily characterized by moderate to severe intellectual disability, true-to-relative microcephaly and brain abnormalities including a thin corpus callosum, cerebellar hypoplasia, cerebral white matter hypoplasia and multi-focal hyperintensity of cerebral white matter on MRI. Obesity and distinctive craniofacial dysmorphism (including brachycephaly, round face, straight eyebrows, synophrys, hypertelorism, epicanthus, wide and depressed nasal bridge, protruding ears with uplifted lobe, downslanting corners of the mouth) are additional features.

INTELLECTUAL DISABILITY-OBESITY-BRAIN MALFORMATIONS-FACIAL DYSMORPHISM SYNDROME Is also known as autosomal recessive intellectual disability due to trappc9 deficiency

• Seizures
• Global developmental delay
• Microcephaly
• Hypertelorism
• Abnormal facial shape

SOURCES: ORPHANET MENDELIAN

Joubert syndrome-26 is an autosomal recessive ciliopathy characterized by global developmental delay associated with cerebellar hypoplasia and variable additional abnormalities, including hypotonia and possibly pituitary abnormalities (summary by Sanders et al., 2015).For a phenotypic description and a discussion of genetic heterogeneity of Joubert syndrome, see {213300}.

• Global developmental delay
• Short stature
• Generalized hypotonia
• Ataxia
• Hypertelorism

SOURCES: OMIM MENDELIAN

Galloway-Mowat syndrome is a renal-neurologic disease characterized by early-onset nephrotic syndrome associated with microcephaly, gyral abnormalities of the brain, 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 ).

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

SOURCES: OMIM MENDELIAN

HeterotaxyHeterotaxy ('heter' meaning 'other' and 'taxy' meaning 'arrangement'), or situs ambiguus, is a developmental condition characterized by randomization of the placement of visceral organs, including the heart, lungs, liver, spleen, and stomach. The organs are oriented randomly with respect to the left-right axis and with respect to one another (Srivastava, 1997). Heterotaxy is a clinically and genetically heterogeneous disorder. Multiple Types of Congenital Heart DefectsCongenital heart defects (CHTD) are among the most common congenital defects, occurring with an incidence of 8/1,000 live births. The etiology of CHTD is complex, with contributions from environmental exposure, chromosomal abnormalities, and gene defects. Some patients with CHTD also have cardiac arrhythmias, which may be due to the anatomic defect itself or to surgical interventions (summary by van de Meerakker et al., 2011). ReviewsObler et al. (2008) reviewed published cases of double-outlet right ventricle and discussed etiology and associations. Genetic Heterogeneity of Visceral HeterotaxySee also HTX2 (OMIM ), caused by mutation in the CFC1 gene (OMIM ) on chromosome 2q21; HTX3 (OMIM ), which maps to chromosome 6q21; HTX4 (OMIM ), caused by mutation in the ACVR2B gene (OMIM ) on chromosome 3p22; HTX5 (OMIM ), caused by mutation in the NODAL gene (OMIM ) on chromosome 10q22; HTX6 (OMIM ), caused by mutation in the CCDC11 gene (OMIM ) on chromosome 18q21; HTX7 (OMIM ), caused by mutation in the MMP21 gene (OMIM ) on chromosome 10q26; and HTX8 (OMIM ), caused by mutation in the PKD1L1 gene (OMIM ) on chromosome 7p12. Genetic Heterogeneity of Multiple Types of Congenital Heart DefectsAn X-linked form of CHTD, CHTD1, is caused by mutation in the ZIC3 gene on chromosome Xq26. CHTD2 (OMIM ) is caused by mutation in the TAB2 gene (OMIM ) on chromosome 6q25. A form of nonsyndromic congenital heart defects associated with cardiac rhythm and conduction disturbances (CHTD3 ) has been mapped to chromosome 9q31. CHTD4 (OMIM ) is caused by mutation in the NR2F2 gene (OMIM ) on chromosome 15q26. CHTD5 (OMIM ) is caused by mutation in the GATA5 gene (OMIM ) on chromosome 20q13. CHTD6 (OMIM ) is caused by mutation in the GDF1 gene (OMIM ) on chromosome 19p13.

HETEROTAXY, VISCERAL, 1, X-LINKED; HTX1 Is also known as situs inversus, complex cardiac defects, and splenic defects, x-linked|laterality, x-linked|dextrocardia with other cardiac malformations

• Hypertelorism
• Failure to thrive
• Cleft palate
• Ventricular septal defect
• Atrial septal defect

SOURCES: MESH OMIM ORPHANET MENDELIAN

MRD13 is an autosomal dominant form of mental retardation associated with variable neuronal migration defects resulting in cortical malformations. More variable features include early-onset seizures and mild dysmorphic features. Some patients may also show signs of peripheral neuropathy, such as abnormal gait, hyporeflexia, and foot deformities (summary by Willemsen et al., 2012 and Poirier et al., 2013).

MENTAL RETARDATION, AUTOSOMAL DOMINANT 13; MRD13 Is also known as mental retardation, autosomal dominant 13, with neuronal migration defects

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

SOURCES: OMIM MENDELIAN