IllnessIntellectual deficit + megalencephaly, differential diagnosis

NGS +

Megalencephaly defines an increased growth of cerebral structures related to dysfunctional anomalies during the various steps of brain development in the neuronal proliferation and/or migration phases. The condition has to be distinguished from macrocephaly that presents with different clinical situations. The disorders associated with megalencephaly are classically defined into 3 groups: idiopathic or benign, metabolic, anatomic. Abnormalities of brain growth can be clinically isolated or occur as part of complex syndromes associated with other neurodevelopmental like intellectual disability. Intellectual disability is a lifelong, debilitating condition.

• Alias: Intellectual disability + megalencephaly
• Alias: Psycho-motor retardation + megalencephaly
• Allelic: Breast cancer, somatic (PIK3CA)
• Allelic: Colorectal cancer, somatic (PIK3CA)
• Allelic: Focal cortical dysplasia, type II, somatic (MTOR)
• Allelic: Gastric cancer, somatic (PIK3CA)
• Allelic: Hepatocellular carcinoma, somatic (PIK3CA)
• Allelic: Keratosis, seborrheic, somatic (PIK3CA)
• Allelic: Macrodactyly, somatic (PIK3CA)
• Allelic: Nevus, epidermal, somatic (PIK3CA)
• Allelic: Nonsmall cell lung cancer, somatic (PIK3CA)
• Allelic: Ovarian cancer, somatic (PIK3CA)
• Alexander disease (GFAP)
• CLAPO syndrome, somatic (PIK3CA)
• CLOVE syndrome, somatic (PIK3CA)
• Cowden syndrome 5 (PIK3CA)
• Intellectual developmental disorder, AD 35 (PPP2R5D)
• Intellectual developmental disorder, AD 36 (PPP2R1A)
• Intellectual developmental disorder, AR 34, + variant lissencephaly (CRADD)
• Leukoencephalopathy, cystic, without megalencephaly (RNASET2)
• Macrocephaly/megalencephaly syndrome, AR (TBC1D7)
• Megalencephalic leukoencephalopathy, subcortical cysts (MLC1)
• Megalencephalic leukoencephalopathy, subcortical cysts 2A (HEPACAM)
• Megalencephalic leukoencephalopathy, subcortical cysts 2B, remitting, with/-out ment. ret. (HEPACAM)
• Megalencephaly-capillary malformation-polymicrogyria syndrome, somatic (PIK3CA)
• Megalencephaly-polymicrogyria-polydactyly-hydrocephalus syndrome 2 (AKT3)
• Megalencephaly-polymicrogyria-polydactyly-hydrocephalus syndrome 3 (CCND2)
• Polyhydramnios, megalencephaly + symptomatic epilepsy (STRADA)
• Smith-Kingsmore syndrome (MTOR)