De Grouchy Syndrome Explained: An Overview of the Cause, Symptoms and Prognosis

Two Types of de Grouchy Syndrome

De Grouchy syndrome is a rare congenital condition caused by a chromosome 18 abnormality; and the disorder has two classified forms, type 1 or type 2. The type of de Grouchy syndrome is classified by the nature of the genetic damage or loss of function.

The deletion of the genes from the short arm of chromosome 18 is considered to be de Grouchy syndrome type 1. When the long arm of chromosome 18 is affected, this is de Grouchy syndrome type 2.

Symptoms of de Grouchy Syndrome

De Grouchy syndrome manifests clinically as mental retardation. The affected person will have a short stature, hypotonia (lack of muscle tone), hearing impairment, and foot deformities. Poor coordination, nystagmus (involuntary eye movement), seizures, a small head, underdeveloped mid-face, deep set eyes, a carp-shaped mouth, and autistic behavior. Foot deformities include clubfoot and abnormal toe placement. There are also many abnormalities related to sexual development. An underdeveloped labia minora, undescended testes, small scrotum and penis are some of these.

Less common symptoms include inner epicanthal folds, slanted spaces between the eyelids, widely spaced eyes and small eyes, and corneal abnormalities.

The symptoms of de Grouchy syndrome have no direct connection with a single gene. As several genes can be lost, it may be that different symptoms are caused by the loss of specific genes.

How is de Grouchy Syndrome Diagnosed?

Suspicion of a chromosomal abnormalities tend to arise due to the presence of birth defects or developmental delays. To effectively diagnose de Grouchy syndrome, a genetic analysis needs to be performed. A common method used is called Fluorescent In Situ Hybridization (FISH). This method visualizes the chromosomes of the patient to see if any part of chromosome 18 is missing. Another method used to diagnose de Grouchy syndrome is Magnetic Resonance Imaging (MRI), but it cannot be used alone to diagnose the disorder. Prenatal diagnosis can also be made through amniocentesis.


The prognosis depends on a number of different factors. These include: the type of de Grouchy syndrome, the severity of the symptoms, and how they develop. A person with de Grouchy syndrome can have a reasonable prognosis or they can be considered severely handicapped. An early diagnosis means that interventions can start sooner which can improve prognosis.


De Grouchy syndrome treatment varies depending on the type and severity of the symptoms. Surgery can be used to correct defects or abnormalities that occur. Abnormalities that can be corrected include a cleft palate, heart defects and many sexual development problems. Physical therapy can help improve lack of muscle tone and other physical issues. Speech therapy, educational support, social and vocational services are also recommended.


Lumrix: de Grouchy Syndrome –

United Leukodystrophy Foundation – 18q Syndrome, What causes 18q syndrome? –