Serpentine Fibula-Polycystic Kidney Syndrome

Elongated serpentine fibulas, bowed lower legs and forearms, bowed radii, polycystic kidneys, small stature, unusual facial appearance, large skull and occipital depression, severe pectus excavatum, hirsutism, and deafness but normal intelligence.

SFPKS.

Most likely autosomal recessive; predominance of affected females raises the possibility of X-linked dominance with lethality in hemizygous affected males.

Unknown.

Clinical and radiological features. Most striking radiological feature is the elongated and deformed S-shaped fibulae. Other features include bowing of forearms and lower legs and metatarsus adductus. Abdominal ultrasonography must be used to confirm the presence of polycystic kidney. Chromosomal study is normal.

Unusual facial appearance: coarse hair, hirsute forehead and neck, marked eyebrows, micrognathia. Skull: large skull with occipital depression in one patient. Thorax: shield chest; pectus excavatum. Urology: polycystic kidney. Other features include short neck, low-set ears, and deafness in some cases. Cardiac: atrial septal defect and patent ductus arteriosus in one report. Growth: small stature in most cases. Intelligence is normal in all cases. Renal function usually well maintained until late.

The cardiac function must be assessed through examination, chest radiography, ECG, and echocardiogram to rule out cardiac defect. Assess the airway for potential difficulty if micrognathia and short neck are present. Biochemistry screen for potassium, creatinine, and urea to assess renal function.

Potential for difficult airway with abnormal facies.

Considerations for cardiac defect include prophylactic antibiotic, avoidance of air embolism, and adequate rehydration.

Melnick-Needles Syndrome (MNS): Characterized by severe typical facies (exophthalmos [frog-like eyes], full red cheeks, high forehead, micrognathia and malalignment of teeth), flaring of the metaphyses of long bones, S-like curvature of bones of legs, irregular constrictions in the ribs, and sclerosis of base of skull. It is caused by mutations in the gene encoding filamin A.

Hajdu Cheney Syndrome: Characterized by acroosteolysis, multiple wormian bones, and hypoplasia of ramus of mandible. The presence of generalized osteoporosis and multiple fractures of the skull, spine and digits, short stature, persistent cranial sutures, early loss of teeth, and joint laxity are reported as features associated in varying degrees. The patients show bathrocephaly (projection of the occipital area and a deep groove at the lambdoidal sutures between the occipital and parietal bones). In addition to micrognathia and narrow high palate, prominent ears may be a feature.

Ter Haar Syndrome: Characterized by bone changes and facial features (frog-like eyes, micrognathia), bilateral glaucoma, congenital heart defect (ventricular septal defect), delay in closure of the anterior fontanel and sclerosis of the base of the skull and mastoids. It is considered an autosomal recessive disorder. Other features include brachycephaly with flat occiput, large anterior fontanel, hypertelorism, anteverted nostrils, thoracolumbar kyphosis, prominent coccyx with skin fold, short hands and feet, flexion deformity of fingers, and clubfeet.