ZELLWEGER SYNDROME (CEREBROHEPATORENAL SYNDROME)
DESCRIPTION A family of diseases of inborn errors of metabolism caused by agenesis or disruption of peroxisomes (subcellular organelles). It follows an autosomal recessive inheritance pattern, with an incidence of 1 in 25,000 to 1 in 50,000 live births. Characteristics include severe developmental delay, sensorineural deafness, renal cortical cysts, retinal dysfunction, hepatomegaly, and characteristic facies (thus, cerebrohepatorenal syndrome). Usually lethal in childhood, rare patients survive into adolescence and adulthood. Positive diagnosis is made by serum assay of very long-chain fatty acids and dihydroxyacetone phosphate acyl transferase. Hyperoxaluria and nephrocalcinosis may also be present. No known treatment exists.
REFERENCE
van Woerden CS, Groothoff JW, Wijburg FA, et al. High incidence of hyperoxaluria in generalized peroxisomal disorders. Mol Genet Metab. 2006;88(4):346–350.
ZINNER SYNDROME
DESCRIPTION Ejaculatory duct obstruction (EDO) resulting from a unilateral seminal vesicle cyst with associated ipsilateral kidney agenesis, the condition is caused by a congenital müllerian/wolffian/utricular abnormality. Although EDO accounts for <1% of infertility, it is a treatable entity, using transurethral resection of ejaculatory duct.
REFERENCE
Pace G, Galatioto GP, Gualà L, et al. Ejaculatory duct obstruction caused by a right giant seminal vesicle with an ipsilateral upper urinary tract agenesia: An embryologic malformation. Fertil Steril.2008;89(2):390–394.
ZIPPER ENTRAPMENT
DESCRIPTION Usually an emergency department presentation, this penile problem usually results from the entrapment of the foreskin between the fastener device and zipper teeth as a result of the caudal motion of the zipper. Often occurs in children 3–6 yr of age. Treatment should not include extraction of the foreskin or urgent circumcision, but instead should involve the release of the zipper median bar using orthopedic bone pliers (see below). An alternate method of release involves cutting the closed portion of the actuator (zipper teeth) with trauma shears to release the closed portion of the zipper from around the tissue.
• To remove a zipper, local anesthetic is injected into the area. Mineral oil is used to lubricate the zipper, and then 1 attempt is made to unzip the zipper. If this attempt is unsuccessful, a sturdy wire cutter (diagonal cutter) is used to cut the median bar on the top of the zipper slider, which connects its front and back plates. Then the slider falls off in 2 pieces, and the zipper teeth come apart readily (Image 
).
REFERENCES
Inoue N, Crook SC, Yamamoto LG. Comparing two methods of emergency zipper release. Am J Emer Med. 2005;23:480–482.
Porter R, ed. Merck Manual of Diagnosis and Therapy. Copyright 2013 by Merck Sharp & Dohme Corp., a subsidiary of Merck & Co, Inc, Whitehouse Station, NJ. Available at http://www.merckmanuals.com/professional/, Accessed April 5, 2014.
ZONA PELLUCIDA BINDING ASSAY
DESCRIPTION An assay used to counsel patients about their chances of success with IVF. Being species-specific, the human sperm-zona pelllucida binding requires human oocytes. Different sources of oocytes can be used, such as postmortem, IVF surplus, or surgical specimens. Oocytes are bisected, and 1/2 of the zona acts as the control. Different preservation methods are available, such as salt storage, dimethyl sulfoxide freezing, or ultra-low-temperature freezing. The assay is essentially composed of 2 steps: Initial attachment, followed by irreversible binding. After repeated rinsing, the number of tightly bound spermatozoa to ZP is counted using phase contrast microscopy. This can be expressed as the hemizona index, which is the number of the patient’s bound spermatozoa divided by the bound spermatozoa from the fertile control donor, multiplied by 1,003. Using a cut off of 35%, the hemizona index has been used by some to predict IVF success rate. (See also Section II: “Sperm Penetration Assay [Hamster Test].”)
REFERENCE
Oehninger S, Franken D, Alexander N, et al. Hemizona assay and its impact on the identification and treatment of human sperm dysfunctions. Andrologia. 1992;24:307–321.