Megalencephaly-Polymicrogyria-Polydactyly-Hydrocephalus syndrome

Alternate names

MPPH syndrome; Megalencephaly and perisylvian polymicrogyria with postaxial polydactyly and hydrocephalus; Megalencephaly, polymicrogyria, and hydrocephalus (MPPH) syndrome; Megalencephaly-polymicrogyria-postaxial polydactyly-hydrocephalus syndrome

Definition

MPPH syndrome is a disorder characterized by the presence of multiple birth defects and developmental delay. Classic signs and symptoms include polymicrogyria, megalencephaly, seizures, polydactyly, and hydrocephalus.

Epidemiology

About 60 affected individuals have been described in the medical literature.

Cause

• Mutations in at least three different genes causes MPPH syndrome, including PIK3R2, AKT3, and CCND2.
• It is not known exactly how mutations within these genes causes MPPH syndrome; however, studies show that they are involved in a number of different functions in the body including vascular, limb, and brain development as well as regulation of growth.

Inheritance

Most cases of MPPH syndrome are new (de novo) in families with no prior history.

Signs and symptoms

• Common signs and symptoms of MPPH syndrome include polymicrogyria, megalencephaly, intellectual disability, seizures, polydactyly, and hydrocephalus.
• Additional signs and symptoms reported in the medical literature include thin corpus callosum, psychomotor impairment (i.e., slowing down of physical reactions, movements, and speech), impaired vision, low muscle tone (hypotonia), connective tissue symptoms including skin elasticity, mild characteristic facial differences, macrosomia (often at birth), and infantile spasms.

Clinical presentation

For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed.

80%-99% of people have these symptoms Hydrocephalus(Too much cerebrospinal fluid in the brain)

• Macrocephaly(Increased size of skull)
• Megalencephaly
• Polymicrogyria(More grooves in brain)
• Postaxial hand polydactyly(Extra little finger)

30%-79% of people have these symptoms

• Abnormal localization of kidney(Abnormal localisation of kidneys)
• Abnormal nasal morphology(Abnormal of nasal shape)
• Depressed nasal bridge(Depressed bridge of nose)
• High forehead
• Hypertelorism(Wide-set eyes)
• Mitral regurgitation
• Narrow mouth(Small mouth)
• Seizure
• Telecanthus(Corners of eye widely separated)
• Ventricular septal defect(Hole in heart wall separating two lower heart chambers)

Diagnosis

The diagnosis of MPPH syndrome is based on physical examination, imaging studies, and genetic testing.

Treatment

Hydrocephalus warrants early neurosurgical intervention. Oromotor difficulties, developmental delays, and epilepsy are treated as per usual clinical care standards.[1].

NIH genetic and rare disease info

• NIH info on Megalencephaly-Polymicrogyria-Polydactyly-Hydrocephalus syndrome

Megalencephaly-Polymicrogyria-Polydactyly-Hydrocephalus syndrome is a rare disease.