LEOPARD syndrome- 1

Overview

LEOPARD syndrome is a rare autosomal dominant, multisystem disease caused by a mutation in the protein tyrosine phosphatase, non-receptor type 11 gene (PTPN11). The disease is a complex of features, mostly involving the skin, skeletal and cardiovascular systems, they may or may not be present in all patients. The nature of how the mutation causes each of the condition's symptoms is not well known, however research is ongoing. Related to Noonan syndrome, LEOPARD syndrome is caused by a different missense mutation of the same gene. LEOPARD syndrome may also be called multiple lentigines syndrome, cardiomyopathic lentiginosis, Gorlin's syndrome II, Capute-Rimoin-Konigsmark-Esterly-Richardson syndrome, or Moynahan syndrome. Noonan syndrome is fairly common (1:1000 to 1:2500 live births), and neurofibromatosis 1 (which was once thought to be related to LEOPARD syndrome) is also common (1:3500), but however no epidemiologic data exists for LEOPARD syndrome

Symptoms

Lentigines - Reddish-brown to dark brown macules (surface skin lesion) generally occurring in a high number (10,000+) over a large portion of the skin, at times higher than 80% coverage. These can even appear inside the mouth (buccal), or on the surface of the eye (scleral). These have irregular borders and range in size from 1 mm in diameter to café-au-lait spot's, several cm's in diameter. Also, some areas of vitiligo-like hypopigmentation may be observed.

Ocular hypertelorism: Wideset eyes, which lead to a similar facial resemblance between patients. Facial abnormalities are the second highest occurring symptom after the lentigines. Abnormalities also include: broad nasal root, prognathism (protruding lower jaw), or low-set, possibly rotated, ears.

Pulmonary stenosis: Narrowing of the pulmonary artery as it exits the heart. Other cardiac abnormalities may be present, including aortic stenosis, or mitral valve prolapse.

Abnormal genitalia: (usually cryptorchidism (retention of testicles in body) or monorchism (single testicle). In female patients, this presents as missing or single ovaries, much harder by nature to detect. Ultrasound imaging is performed at regular intervals, from the age of 1 year, to determine if ovaries are present.

Retarded growth: Slow, or stunted growth. Most newborns with this syndrome are of normal birth weight and length, but will often slow within the first year.

Deafness: Sensorineural (nerve deafness).

Diagnosis

The presence of the disease can be confirmed with a genetic test. In a study of 10 infants with clinical indications of LEOPARD syndrome prior to their first birthday, 8 (80%) patients were confirmed to have the suspected mutation. An additional patient, with the suspected mutation was subsequently found to have NF1, following evaluation of the mother. There are 5 identified allelic variants responsible for LEOPARD syndrome. Y279C, T468M, A461T, G464A, and Q510P which seems to be a unique familial mutation, in that all other variants are caused by transition errors, rather than transversion.

Prognosis

LEOPARD syndrome is not a life threatening diagnosis, most people diagnosed with the condition live normal lives. Obstructive cardiomyopathy and other pathologic findings involving the cardiovascular system may be a cause of death in those whose cardiac deformities are profound. It is suggested that, once diagnosed, individuals be routinely followed by a cardiologist, endocrinologist, dermatologist, and other appropriate specialties as symptoms present. It is recommended that those with the syndrome who are capable of having children seek genetic counseling before deciding to have children. As the syndrome presents frequently as a forme fruste (incomplete, or unusual form) variant, an examination of all family members must be undertaken. As an autosomal dominant trait there is a fifty percent chance with each child, that they will also be born with the syndrome. This does not take into account the possibility of the gene mutating, on its own, in a child of a LEOPARD syndrome patient who does not inherit the gene from the affected parent. Since the syndrome has a variable penetrance and expression, one generation may have a mild expression of the syndrome, while the next may be profoundly affected. Once a decision to have children is made, and the couple conceives, the fetus is monitored during the pregnancy for cardiac evaluation. If a gross cardiac malformation is found, parents receive counseling on continuing with the pregnancy.

Treatment

1. For those with endocrine issues (low levels of thyrotopin [a pituitary hormone responsible for regulating thyroid hormones], follicle stimulating hormone) drug therapy is recommended.

2. For those who are disturbed by the appearance of lentigines, cryosurgery may be beneficial. Due to the large number of lentigines this may prove time consuming. An alternative treatment with tretinoin or hydroquinone creams may help.

3. Drug therapies for those with cardiac abnormalities, as those abnormalities become severe enough to warrant the use of these therapies. ECG's are mandatory prior to any surgical interventions, due to possible arrythmia.