A Method Characterization Study to Evaluate Thermoregulatory Sweat Production in Healthy Volunteers and Patients With ROSAH Syndrome)

A Method Characterization Study to Evaluate Thermoregulatory Sweat Production in Healthy Volunteers and Patients With ROSAH Syndrome

This study is designed to characterize a new quantitative method for measuring sweat production induced by controlled heat exposure. Approximately 20 healthy volunteers and up to 10 patients with ROSAH syndrome will be enrolled. Sweat production will be quantified using a gravimetric filter-paper technique during standardized 30-minute heat exposure in a temperature-controlled sauna chamber. Each participant will complete three repeated testing sessions. The study will also pilot a questionnaire to evaluate the self-reported impact and severity of hypohidrosis/anhidrosis.

Study Overview

• Status: Not yet recruiting
• Conditions: Hypohidrosis; ROSAH Syndrome; Anhidrosis
• Intervention / Treatment: Procedure: Standardized Controlled Heat Exposure With Gravimetric Sweat Collection

Detailed Description

This multicenter, controlled-environment, repeated-measures study is designed as a physiological challenge test. The study will be initiated in healthy volunteers to characterize the feasibility, reproducibility, and reference distribution of the sweat measurement method under controlled heat exposure. Upon confirmation of the method's suitability, the study will proceed to enroll participants with ROSAH syndrome. Each participant will complete three heat-exposure sessions in a sauna, separated by 1-3 days, with all sessions completed within a maximum of one week. The primary outcome is Total Gravimetric Sweat Production (TGSP). Safety evaluations will include monitoring of adverse events, vital signs, and body temperature.

• Study Type: Interventional
• Enrollment (Estimated): 30
• Phase: Not Applicable

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Male or female participants 12 to 65 years of age at screening.
• Adolescent participants must be Tanner stage IV or V or have reached an equivalent level of sexual maturity.
• For the healthy-volunteer cohort, the participant must be considered healthy based on medical history and investigator assessment.
• For the ROSAH syndrome cohort, the participant must have a genetically and clinically confirmed diagnosis of ROSAH syndrome and must be considered clinically stable by the investigator.
• Able and willing to complete three controlled sauna heat-exposure tests.
• Able to remain seated in a temperature-controlled sauna chamber for up to 30 minutes.
• Willing to wear only underwear during testing; female participants may wear a bra.
• Willing to have hair at testing sites trimmed or shaved if necessary.
• Able to drink 300 mL of water before each test.
• Able and willing to comply with study requirements, instructions, and protocol restrictions and likely to complete the study as planned.
• Able to provide written informed consent.
• For minors, written informed consent must be provided by a parent or legal representative, and written assent must be provided by the participant.

Exclusion Criteria:

• Baseline body temperature greater than 37.5°C on the day of testing.
• Fever, acute infection, or acute illness within 7 days before testing.
• History of heat stroke, severe heat intolerance, heat-associated syncope, or severe dehydration.
• Clinically significant cardiovascular disease, uncontrolled hypertension, cardiac arrhythmia, or unstable respiratory disease.
• Severe anemia or unstable cytopenia, in the investigator's judgment.
• Active skin disease, wound, dermatitis, or skin infection at a filter paper placement site.
• Pregnant or breastfeeding.
• Current use of medication that may substantially affect sweating or thermoregulation unless approved by the investigator, including anticholinergic agents, systemic beta blockers, diuretics, selected antihistamines, or medications that reduce heat tolerance.
• Use of depilatory cream, waxing, an epilator, or another chemical or mechanical hair-removal method other than shaving from 7 days before the first sweat test through the final sweat test.
• Laser, intense pulsed light, or other energy-based hair removal within 3 months before screening.
• Unable to comply with clothing, privacy, or testing requirements.
• Any other condition that, in the investigator's judgment, would create an unacceptable risk or interfere with interpretation of the study results.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Controlled Heat Exposure and Gravimetric Sweat Assessment; Approximately 20 healthy volunteers and up to 10 participants with genetically confirmed ROSAH syndrome will undergo three standardized passive heat-exposure sessions in a temperature-controlled sauna chamber. Each session will last approximately 30 minutes, will be separated by at least 1 day, and all three sessions will be completed within 7 days. Preweighed filter papers will be placed at the chest, back, axilla, forehead, and forearm and reweighed after exposure to quantify total and regional sweat production. Physiologic and environmental parameters will be monitored throughout the procedure.

Procedure: Standardized Controlled Heat Exposure With Gravimetric Sweat Collection; Participants will drink 300 mL of water before testing and will sit in a temperature-controlled sauna chamber for approximately 30 minutes. The mean internal exposure temperature will be maintained above 42°C and below 44°C, with an adjustable nominal operating set point of approximately 45°C. Preweighed filter papers will be attached to prespecified anatomical sites and will be removed and reweighed immediately after exposure using a calibrated analytical balance. Body temperature, heart rate, symptoms, sauna temperature, and relative humidity will be monitored. The procedure will be stopped early if prespecified safety or intolerance criteria are met. The procedure will be repeated three times, with sessions at least 1 day apart and completed within 7 days.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Total Gravimetric Sweat Production (TGSP)	TGSP is defined as the sum of sweat mass collected from all prespecified and evaluable anatomical sites during a standardized heat-exposure session. For each site, sweat mass is calculated as the post-exposure filter paper weight minus the pre-exposure filter paper weight. TGSP will be reported in milligrams and may also be standardized by filter paper area according to the statistical analysis plan.	During each of three approximately 30-minute heat-exposure sessions, with sessions at least 1 day apart and all three sessions completed within 7 days.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Regional Gravimetric Sweat Production by Anatomical Site	Sweat mass at the chest, back, axilla, forehead, and forearm will be calculated separately as the post-exposure filter paper weight minus the pre-exposure filter paper weight. Results will be reported in milligrams and may also be standardized by filter paper area.	During each of three approximately 30-minute heat-exposure sessions, with sessions at least 1 day apart and completed within 7 days.
Test-Retest Reliability of Total Gravimetric Sweat Production	Short-term test-retest reliability of TGSP across the three heat-exposure sessions will be assessed using the intraclass correlation coefficient and graphical repeated-measures assessments.	Across the three heat-exposure sessions completed within 7 days.
Within-Participant Variability of Total Gravimetric Sweat Production	Within-participant variability in TGSP across the three sessions will be summarized using within-participant standard deviation and coefficient of variation.	Across the three heat-exposure sessions completed within 7 days.
Test-Retest Reliability and Variability of Regional Sweat Production	Test-Retest Reliability and Variability of Regional Sweat Production	Across the three heat-exposure sessions completed within 7 days.
Total and Regional Sweat Production by Clinical Group, Sex, and Age Category	TGSP and regional sweat production will be summarized descriptively by clinical group (healthy volunteers and participants with ROSAH syndrome), sex, and age category (adolescents and adults). Comparisons are exploratory and are not powered for confirmatory hypothesis testing.	During the three heat-exposure sessions completed within 7 days.
Sauna Chamber Temperature Stability	Sauna chamber temperature will be recorded continuously or at protocol-defined frequent intervals. Stability will be summarized using descriptive statistics and the extent of time within the protocol-defined operating range.	Throughout each approximately 30-minute heat-exposure session during the three sessions completed within 7 days.
Sauna Chamber Relative Humidity Stability	Sauna chamber relative humidity will be recorded continuously or at protocol-defined frequent intervals and summarized descriptively to characterize environmental consistency across sessions.	Throughout each approximately 30-minute heat-exposure session during the three sessions completed within 7 days.
Change in Body Temperature During Controlled Heat Exposure	Body temperature will be measured before sauna entry, at least every 5 minutes during exposure if not continuously monitored, at the end of exposure, and during recovery when clinically indicated. Change from the pre-exposure value and maximum observed temperature will be summarized.	Before, during, immediately after, and during recovery from each of the three heat-exposure sessions completed within 7 days.
Heat-Exposure Sessions Terminated Early Due to Body Temperature of 38.0°C or Higher or Participant Intolerance	The number and percentage of planned heat-exposure sessions that are terminated early because body temperature reaches or exceeds 38.0°C, the participant requests discontinuation, or the investigator identifies clinically significant intolerance will be summarized.	During the three heat-exposure sessions completed within 7 days.
Incidence, Type, and Severity of Adverse Events and Heat-Related Intolerance Events	Adverse events and procedure-related intolerance events will be collected and summarized by event type, severity, seriousness, and relationship to study procedures. Events of interest include heat intolerance, dizziness, presyncope or syncope, headache, nausea or vomiting, fatigue, palpitations, skin irritation, and clinically significant body-temperature elevation.	From initiation of the first study procedure through the follow-up assessment, up to approximately 17 days per participant.
Anhidrosis/Hypohidrosis Impact Questionnaire Total Score	The questionnaire contains six scored items covering heat intolerance, frequency of overheating, activity limitation, use of cooling measures, perceived ability to sweat, and overheating-related symptoms. Each item is scored from 0 to 4; the total score ranges from 0 to 24, with higher scores indicating greater heat intolerance or impact of impaired sweating.	Before the first heat-exposure session and 8 to 10 days after the final heat-exposure session.
Change in Anhidrosis/Hypohidrosis Impact Questionnaire Total Score	Change in questionnaire total score will be calculated as the follow-up total score minus the baseline total score. Item-level changes may also be summarized descriptively.	From before the first heat-exposure session to 8 to 10 days after the final heat-exposure session.
Test-Retest Reliability of the Anhidrosis/Hypohidrosis Impact Questionnaire	Short-term stability and test-retest reliability of questionnaire total scores will be evaluated using paired descriptive summaries, correlations, intraclass correlation coefficients, and graphical assessments, as appropriate.	Between the baseline assessment before the first heat-exposure session and the follow-up assessment 8 to 10 days after the final heat-exposure session.

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Spearman Correlation Between Baseline Anhidrosis/Hypohidrosis Impact Questionnaire Total Score and Mean Total Gravimetric Sweat Production (TGSP)	Spearman correlation will be used to assess the relationship between the Anhidrosis/Hypohidrosis Impact Questionnaire total score and Total Gravimetric Sweat Production (TGSP). The questionnaire includes 6 scored items, each rated from 0 to 4, yielding a total score of 0 to 24 points; higher scores indicate greater heat intolerance or impact of impaired sweating. TGSP is measured using a gravimetric filter-paper method and is defined as the sum of post-exposure minus pre-exposure filter-paper weights across all evaluable anatomical sites, expressed in milligrams (mg). The outcome will be reported as Spearman's rho, ranging from -1 to +1.	Baseline questionnaire assessment before the first heat-exposure session and TGSP measurements from the three heat-exposure sessions completed within 7 days.
Patient-Reported Change in Heat Tolerance	The change-impression item will be summarized by response category and may be encoded from -3 (very much worse) to +3 (very much improved). In this nontherapeutic study, the item should refer to change since the previous questionnaire assessment rather than change since starting treatment.	At the follow-up assessment 8 to 10 days after the final heat-exposure session.

Collaborators and Investigators

• Sponsor: The Third Xiangya Hospital of Central South University
• Collaborators: Drug Farm Inc

Study record dates

Study Major Dates

• Study Start (Estimated): August 15, 2026
• Primary Completion (Estimated): December 31, 2027
• Study Completion (Estimated): December 31, 2027

Study Registration Dates

• First Submitted: August 31, 2026
• First Submitted That Met QC Criteria: September 9, 2026
• First Posted (Actual): September 10, 2026

Study Record Updates

• Last Update Posted (Actual): September 10, 2026
• Last Update Submitted That Met QC Criteria: September 9, 2026
• Last Verified: September 1, 2026

More Information

Terms related to this study

• Keywords: Healthy Volunteers; Thermoregulation; Sweat Test; Weighted Filter Paper; ROSAH Syndrome; ALPK1 Gene
• Additional Relevant MeSH Terms: Skin Diseases; Sweat Gland Diseases; Skin and Connective Tissue Diseases; Hypohidrosis
• Other Study ID Numbers: DF-GSP-1001

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No