Potter syndrome

Potter syndrome is a rare condition characterized by physical features of the fetus that develop when there is too little amniotic fluid in the uterus during pregnancy (oligohydramnios). Complete absence of amniotic fluid is called anhydramnios. Amniotic fluid supports, cushions, and protects the developing fetus. If amniotic fluid is too low, the abnormal pressure on the fetus during pregnancy can lead to certain physical features, such as characteristic facial appearance or skeletal abnormalities.

If oligohydramnios is present from early pregnancy, the lungs are also underdeveloped (pulmonary hypoplasia), which can cause severe breathing difficulties. The most common cause of this condition is the absence of both kidneys (bilateral renal agenesis). This is sometimes referred to as classic Potter syndrome.

Potter syndrome may also result from other conditions, such as polycystic kidney disease, malformed (dysplastic) or underdeveloped (hypoplastic) kidneys, and obstructive uropathy, in which urine cannot drain from the bladder and backs up into the kidneys. Sometimes, later in pregnancy, leakage of amniotic fluid may occur; this does not lead to Potter syndrome.

Potter syndrome is an extremely severe condition and often results in death at birth or shortly afterward, mainly due to pulmonary hypoplasia.

Some physicians consider the term Potter sequence more appropriate than Potter syndrome, because although signs and symptoms may vary among affected newborns, the sequence of events leading to the condition is the same. Some clinicians use Potter sequence to refer to a milder form, but in medical literature the terms Potter syndrome, Potter sequence, and oligohydramnios sequence are all used. The condition was first described in 1946 by Edith Potter, a pathologist in Chicago, Illinois.

Diagnosis:
The signs and symptoms of Potter syndrome can vary among individual newborns. However, the condition is associated with severe complications affecting the developing fetus and is often fatal at birth or shortly thereafter. When Potter syndrome is caused by bilateral renal agenesis, it is incompatible with life. Potter syndrome due to other causes is also frequently fatal at or shortly after birth, although there is a slightly higher chance of survival. Infants who survive the neonatal period usually develop chronic lung disease and chronic kidney failure.

Due to the lack of amniotic fluid protecting the developing fetus, normal pressure from the uterine walls can affect fetal growth and development. This pressure can cause distinctive facial features, including a receding chin, a flattened and depressed nasal bridge, widely spaced eyes (hypertelorism), low-set ears lacking cartilage (Potter ears), abnormally prominent epicanthal folds, and a fold under the lower lip. This collection of facial features is sometimes referred to as “Potter facies.”

Due to abnormalities of the kidneys, there is usually a lack of urine production. Absence (agenesis) of both kidneys is the most common defect associated with Potter syndrome. The kidneys may also be malformed (dysplastic) or damaged due to broader syndromes affecting the kidneys, such as polycystic kidney disease, a group of rare disorders characterized by the development of multiple cysts in the kidneys.

The lungs may be underdeveloped (pulmonary hypoplasia), and most newborns experience severe respiratory complications after birth (respiratory distress).

Sometimes abnormalities occur in the development of the arms and legs, incomplete formation of half of a vertebra (hemivertebrae), absence of the lower part of the spine (sacral agenesis), congenital heart defects, or eye abnormalities such as cataract or displacement/prolapse of the eye lens.

Infants with Potter syndrome are often born prematurely and are small for gestational age, meaning they are smaller than expected for the duration of pregnancy.

Potter syndrome is a rare disorder, and the exact incidence or prevalence is not known. The main cause, bilateral renal agenesis, occurs in about 1 in 5,000 fetuses and accounts for approximately 20% of Potter syndrome cases. The incidence of other causes is not known. Overall estimates of incidence or prevalence range from 1 in 4,000 to 1 in 10,000 births. Several studies have shown that male newborns are affected more often than female newborns, likely due to obstructive uropathy occurring more frequently in males.

Treatment:
There is no treatment for Potter syndrome caused by bilateral absence of the kidneys, as this condition is not compatible with life. Efforts should be made to ensure that the entire family receives support for coping with grief and appropriate counseling. Genetic counseling is recommended. Psychosocial support for the whole family is also essential.

Newborns with Potter syndrome due to other causes usually require mechanical ventilation. Resuscitation may also be necessary. Decisions regarding resuscitation are made in close cooperation with parents, physicians, and the entire medical team.

In some newborns with partially functioning kidneys and sufficient lung function, dialysis may be required, which is an intensive and burdensome treatment for neonates.

• Chronic lung diseases
• Chronic kidney failure
• “Potter facies” – characteristic facial features including a recessed chin; flattened and depressed nasal bridge; widely spaced eyes (hypertelorism); low-set ears lacking cartilage (Potter ears); prominent epicanthal folds (abnormally pronounced skin folds at the inner corners of the eyes); and a fold beneath the lower lip