PAFAH1B1-related lissencephaly/subcortical band heterotopia (SBH) comprises a spectrum of severity. Affected newborns typically have mild-to-moderate hypotonia, feeding difficulties, and poor head control. During the first years, neurologic examination typically demonstrates poor visual tracking and response to sounds, axial hypotonia, and mild distal spasticity that can transition over time to more severe spasticity. Seizures occur in more than 90% of individuals with lissencephaly and often include infantile spasms. Seizures are often drug resistant, but even with good seizure control, the best developmental level achieved (excluding the few individuals with partial lissencephaly) is the equivalent of about age three to five months. In individuals with PAFAH1B1-related lissencephaly/SBH, developmental delay ranges from mild to severe. Other findings in PAFAH1B1-related lissencephaly/SBH include feeding issues and aspiration (which may result in need for gastrostomy tube placement), progressive microcephaly, and occasional developmental regression.

Fukuyama congenital muscular dystrophy (FCMD) is characterized by hypotonia, symmetric generalized muscle weakness, and CNS migration disturbances that result in changes consistent with cobblestone lissencephaly with cerebral and cerebellar cortical dysplasia. Mild, typical, and severe phenotypes are recognized. Onset typically occurs in early infancy with poor suck, weak cry, and floppiness. Affected individuals have contractures of the hips, knees, and interphalangeal joints. Later features include myopathic facial appearance, pseudohypertrophy of the calves and forearms, motor and speech delays, intellectual disability, seizures, ophthalmologic abnormalities including visual impairment and retinal dysplasia, and progressive cardiac involvement after age ten years. Swallowing disturbance occurs in individuals with severe FCMD and in individuals older than age ten years, leading to recurrent aspiration pneumonia and death.

Congenital muscular dystrophy-dystroglycanopathy with brain and eye anomalies (type A), which includes both the more severe Walker-Warburg syndrome (WWS) and the slightly less severe muscle-eye-brain disease (MEB), is an autosomal recessive disorder with characteristic brain and eye malformations, profound mental retardation, congenital muscular dystrophy, and death usually in the first years of life. It represents the most severe end of a phenotypic spectrum of similar disorders resulting from defective glycosylation of DAG1 (128239), collectively known as 'dystroglycanopathies' (Beltran-Valero de Bernabe et al., 2004). For a general phenotypic description and a discussion of genetic heterogeneity of muscular dystrophy-dystroglycanopathy type A, see MDDGA1 (236670).

Congenital muscular dystrophy-dystroglycanopathy with brain and eye anomalies (type A), which includes both the more severe Walker-Warburg syndrome (WWS) and the slightly less severe muscle-eye-brain disease (MEB), is an autosomal recessive disorder with characteristic brain and eye malformations, profound mental retardation, congenital muscular dystrophy, and death usually in the first years of life. It represents the most severe end of a phenotypic spectrum of similar disorders resulting from defective glycosylation of alpha-dystroglycan (DAG1; 128239), collectively known as 'dystroglycanopathies' (summary by Roscioli et al., 2012). For a general phenotypic description and a discussion of genetic heterogeneity of muscular dystrophy-dystroglycanopathy type A, see MDDGA1 (236670).

Congenital muscular dystrophy-dystroglycanopathy with brain and eye anomalies (type A) is an autosomal recessive disorder with congenital muscular dystrophy resulting in muscle weakness early in life and brain and eye anomalies. It is usually associated with delayed psychomotor development and shortened life expectancy. The phenotype includes the alternative clinical designations Walker-Warburg syndrome (WWS) and muscle-eye-brain disease (MEB). The disorder represents the most severe end of a phenotypic spectrum of similar disorders resulting from defective glycosylation of alpha-dystroglycan (DAG1; 128239), collectively known as dystroglycanopathies (summary by Stevens et al., 2013). For a general phenotypic description and a discussion of genetic heterogeneity of muscular dystrophy-dystroglycanopathy type A, see MDDGA1 (236670).

Any complex cortical dysplasia with other brain malformations in which the cause of the disease is a mutation in the KIF2A gene.

Any complex cortical dysplasia with other brain malformations in which the cause of the disease is a mutation in the TUBG1 gene.

Congenital muscular dystrophy-dystroglycanopathy with brain and eye anomalies (type A) is an autosomal recessive disorder with characteristic brain and eye malformations, profound mental retardation, and congenital muscular dystrophy. The phenotype includes the alternative clinical designation Walker-Warburg syndrome (WWS), which is associated with death in infancy. The disorder represents the most severe end of a phenotypic spectrum of similar disorders resulting from defective glycosylation of alpha-dystroglycan (DAG1), collectively known as 'dystroglycanopathies' (summary by Geis et al., 2013 and Riemersma et al., 2015). For a general phenotypic description and a discussion of genetic heterogeneity of muscular dystrophy-dystroglycanopathy type A, see MDDGA1 (236670).

Lissencephaly-7 with cerebellar hypoplasia (LIS7) is a severe neurodevelopmental disorder characterized by lack of psychomotor development, facial dysmorphism, arthrogryposis, and early-onset intractable seizures resulting in death in infancy (Magen et al., 2015). For a general description and a discussion of genetic heterogeneity of lissencephaly, see LIS1 (607432).

Congenital muscular dystrophy-dystroglycanopathy with brain and eye anomalies (type A), which includes both the more severe Walker-Warburg syndrome (WWS) and the slightly less severe muscle-eye-brain disease (MEB), is a genetically heterogeneous autosomal recessive disorder with characteristic brain and eye malformations, profound mental retardation, congenital muscular dystrophy, and early death. The phenotype commonly includes cobblestone (type II) lissencephaly, cerebellar malformations, and retinal malformations. More variable features include macrocephaly or microcephaly, hypoplasia of midline brain structures, ventricular dilatation, microphthalmia, cleft lip/palate, and congenital contractures (Dobyns et al., 1989). Those with a more severe phenotype characterized as Walker-Warburg syndrome often die within the first year of life, whereas those characterized as having muscle-eye-brain disease may rarely acquire the ability to walk and to speak a few words. These are part of a group of disorders resulting from defective glycosylation of DAG1 (128239), collectively known as 'dystroglycanopathies' (Godfrey et al., 2007). Genetic Heterogeneity of Congenital Muscular Dystrophy-Dystroglycanopathy with Brain and Eye Anomalies (Type A) Muscular dystrophy-dystroglycanopathy with brain and eye anomalies (type A) is genetically heterogeneous and can be caused by mutation in other genes involved in DAG1 glycosylation: see MDDGA2 (613150), caused by mutation in the POMT2 gene (607439); MDDGA3 (253280), caused by mutation in the POMGNT1 gene (606822); MDDGA4 (253800), caused by mutation in the FKTN gene (607440); MDDGA5 (613153), caused by mutation in the FKRP gene (606596); MDDGA6 (613154), caused by mutation in the LARGE gene (603590); MDDGA7 (614643), caused by mutation in the ISPD gene (CRPPA; 614631); MDDGA8 (614830) caused by mutation in the GTDC2 gene (POMGNT2; 614828); MDDGA9 (616538), caused by mutation in the DAG1 gene (128239); MDDGA10 (615041), caused by mutation in the TMEM5 gene (RXYLT1; 605862); MDDGA11 (615181), caused by mutation in the B3GALNT2 gene (610194); MDDGA12 (615249), caused by mutation in the SGK196 gene (POMK; 615247); MDDGA13 (615287), caused by mutation in the B3GNT1 gene (B4GAT1; 605517); and MDDGA14 (615350), caused by mutation in the GMPPB gene (615320).

A congenital cortical development anomaly due to abnormal neuronal migration involving neocortical and hippocampal lamination, corpus callosum, cerebellum and brainstem. A large clinical spectrum can be observed, from children with severe epilepsy and intellectual and motor deficit to cases with severe cerebral dysgenesis in the antenatal period leading to pregnancy termination due to the severity of the prognosis.

Lissencephaly-8 (LIS8) is an autosomal recessive neurologic disorder characterized by delayed psychomotor development, intellectual disability with poor or absent speech, early-onset refractory seizures, and hypotonia. Brain imaging shows variable features, including cortical gyral abnormalities and hypoplasia of the corpus callosum, brainstem, and cerebellum (Jerber et al., 2016). For a general description and a discussion of genetic heterogeneity lissencephaly, see LIS1 (607432).

DCX-related disorders include the neuronal migration disorders: Classic thick lissencephaly (more severe anteriorly), usually in males. Subcortical band heterotopia (SBH), primarily in females. Males with classic DCX-related lissencephaly typically have early and profound cognitive and language impairment, cerebral palsy, and epileptic seizures. The clinical phenotype in females with SBH varies widely with cognitive abilities that range from average or mild cognitive impairment to severe intellectual disability and language impairment. Seizures, which frequently are refractory to anti-seizure medication, may be either focal or generalized and behavioral problems may also be observed. In DCX-related lissencephaly and SBH the severity of the clinical manifestation correlates roughly with the degree of the underlying brain malformation as observed in cerebral imaging.

PAFAH1B1-related lissencephaly/subcortical band heterotopia (SBH) comprises a spectrum of severity. Affected newborns typically have mild-to-moderate hypotonia, feeding difficulties, and poor head control. During the first years, neurologic examination typically demonstrates poor visual tracking and response to sounds, axial hypotonia, and mild distal spasticity that can transition over time to more severe spasticity. Seizures occur in more than 90% of individuals with lissencephaly and often include infantile spasms. Seizures are often drug resistant, but even with good seizure control, the best developmental level achieved (excluding the few individuals with partial lissencephaly) is the equivalent of about age three to five months. In individuals with PAFAH1B1-related lissencephaly/SBH, developmental delay ranges from mild to severe. Other findings in PAFAH1B1-related lissencephaly/SBH include feeding issues and aspiration (which may result in need for gastrostomy tube placement), progressive microcephaly, and occasional developmental regression.

Lissencephaly-10 (LIS10) is a neurologic disorder characterized by variably delayed development with mildly to moderately impaired intellectual development and language delay, as well as seizures, which are often intractable. There is a spectrum of severity, with some patients having normal early development and only borderline to mild cognitive impairment. Brain imaging shows features consistent with neuronal migration defects, including posterior-predominant lissencephaly, pachygyria, agyria, and subcortical band heterotopia (summary by Tsai et al., 2020). For a general description and a discussion of genetic heterogeneity of lissencephaly, see LIS1 (607432).