The SLO/RSH Foundation is pleased to present information about current studies recruiting children/adults affected by Smith-Lemli-Opitz  Syndrome.

Clinical Studies

7001: Smith-Lemli-Opitz Syndrome: A Longitudinal Clinical Study of Patients Receiving Cholesterol Supplementation

Status: Recruiting

Study Summary

The purpose of this study is to learn as much as possible about Smith-Lemli-Opitz Syndrome (SLOS) by following a large group of affected children and adults over time. In this study, we will measure cholesterol and other similar chemicals in blood and urine, evaluate development and behavior, do limited medical evaluation, and carry out imaging studies (brain MRIs (magnetic resonance imaging)). This study will help researchers:

  • learn more about what causes the problems in SLOS and how those problems change with age,
  • note differences in features of SLOS among those affected,
  • evaluate the effect of giving extra cholesterol in this condition, and
  • develop ways to evaluate whether treatments developed in the future will be helpful.

Please Note: The Rare Diseases Clinical Research Network will make every effort to enroll all the patients we can, but we cannot make any guarantees that we will be able to enroll everyone in a particular study who wants to participate.


Smith-Lemli-Opitz syndrome (SLOS) is a disorder of cholesterol production by the body. It is caused by changes in the DHCR7 gene, which is the blueprint for an enzyme called 7-dehydrocholesterol- delta7-reductase. This enzyme is necessary for the production of cholesterol by the body. People affected by SLOS often have malformations of major organs, poor weight gain (often accompanied by poor height growth and feeding difficulties) and intellectual disability or learning problems.

The features of SLOS are thought to be related to low cholesterol levels and a buildup of toxic cholesterol precursors (substances from which cholesterol is formed). However, the clinical and biochemical properties of SLOS are not completely understood. Despite the widespread use of cholesterol supplementation (increasing dietary cholesterol), there is no proven therapy. It is therefore important to better characterize the disease and its progression while patients are receiving cholesterol. The study will contribute to creating a comprehensive SLOS clinical registry and will identify markers for diagnostic testing, screening and measuring outcomes in future studies of treatment.

Research questions:

The goal of the study is to describe the SLOS disease progression and identify correlations between clinical, biochemical and physiological features of the disease in patients receiving cholesterol supplementation.

The main research question is: does cholesterol supplementation improve I.Q. and behavior?

Other research questions include:

  1. Does cholesterol supplementation change the whole body cholesterol content in patients with SLOS? and
  2. Does cholesterol supplementation change brain development as shown by MRI?

About this Study

Type of study: Natural history, interventional (because to participate, patients must be on cholesterol supplementation)

Length of study: Four years (2010 – 2014 and beyond)

Number of participants: 80-100

Methods of examination/treatment:

Participants are asked to come once a year to the research centers for a 3 to 5 day inpatient visit. During this visit, they will undergo a comprehensive clinical and metabolic evaluation that includes:

  • blood draws (collection of blood from a vein for laboratory testing),
  • urine collections,
  • feeding / swallowing / oral motor assessments,
  • behavioral and developmental testing,
  • brain MRI
  • dietary cholesterol intake assessment.

Changes in learning or intellectual outcomes over time will be correlated with cholesterol intake, biochemical markers, and changes in whole body cholesterol content.


To be eligible for this study, patients must:

  • have a confirmed diagnosis of SLOS and
  • be able to travel to a STAIR site and participate in study procedures.

Anyone meeting these eligibility criteria can participate. This includes:

  • Patients currently followed at STAIR sites and already enrolled in research studies
  • Patients referred to STAIR by their physicians, and
  • Patients who are not currently participating in any research but directly contact STAIR sites.

How to participate

In order to participate in a study, you must personally contact the study coordinator of any of the participating institutions by phone or by e-mail. Please use the information below to inquire about participation.


  • Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda Sandra K. Conley, RN, MS, CPNP Study Coordinator Phone: 301-594-2005 E-mail:


  • University of Nebraska Medical Center, Omaha Machelle Zink, RN Study Coordinator Phone: 402-559-5698 E-mail:


  • Cincinnati Children’s Hospital Medical Center, Cincinnati Donna Buckley, M.Ed, CCRP Study Coordinator/CTRC Phone: 513-636-8549 E-mail:


  • Oregon Health & Science University, Portland Abigail Hata, MS, CGC Study Coordinator, Board Certified Genetic Counselor Phone: 503-418-1061 E-mail:


  • Children’s Hospital of Pittsburgh of University of Pittsburgh Medical Center, Pittsburgh Nancy Perrott, RD, LDN Study Coordinator, Metabolic Dietitian Phone: (412) 692-3150 E-mail:


Be notified when new locations open for this study!

Join the Contact Registry for Smith-Lemli-Opitz Syndrome