Seizures-scoliosis-macrocephaly syndrome
Learn about Seizures-scoliosis-macrocephaly syndrome, its reported features, relevant specialists, and questions to discuss at a medical consultation.
Also known as: SSM syndrome
The sources compiled here do not cover: diagnosis, treatment, prevention, prognosis. Ask the treating doctor about these.
What it is
From: Orphanet
Seizures-scoliosis-macrocephaly syndrome is a rare, genetic neurometabolic disorder characterized by seizures, macrocephaly, delayed motor milestones, moderate intellectual disability, scoliosis with no exostoses, muscular hypotonia present since birth, as well as renal dysfunction. Coarse facial features (including hypertelorism and long hypoplastic philtrum) and bilateral cryptorchidism (in males) are also commonly reported. Additional manifestations include abnormal gastrointestinal motility (resulting in constipation, diarrhea, gastroesophageal reflux and dysphagia), gait disturbances, strabismus and ventricular septal defects.
Reported clinical features and what the terms mean
The following findings are associated with this condition in Orphanet. They are not a checklist for diagnosing yourself, and they do not all occur in every affected person. Some are examination, imaging or laboratory findings that cannot be recognised at home.
The frequency labels describe how often a finding was reported among people with the condition in the source. They do not give the chance that a person with that symptom has the condition. Definitions below reproduce HPO terminology; they explain the term, not the likely severity in an individual.
- Delayed speech and language development · Very frequent (99-80%)
- A degree of language development that is significantly below the norm for a child of a specified age.
- Global developmental delay · Very frequent (99-80%)
- A delay in the achievement of motor or mental milestones in the domains of development of a child, including motor skills, speech and language, cognitive skills, and social and emotional skills. This term should only be used to describe children younger than five years of age.
- Reduced bone mineral density · Very frequent (99-80%)
- A reduction of bone mineral density, that is, of the amount of matter per cubic centimeter of bones.
- Seizure · Very frequent (99-80%)
- A seizure is an intermittent abnormality of nervous system physiology characterized by a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain.
- Abnormal cardiovascular system morphology · Frequent (79-30%)
- Any structural anomaly of the heart and blood vessels.
- Abnormality of the kidney · Frequent (79-30%)
- An abnormality of the kidney.
- Abnormality of the outer ear · Frequent (79-30%)
- An abnormality of the external ear.
- Abnormality of the skin · Frequent (79-30%)
- An abnormality of the skin.
- Autism · Frequent (79-30%)
- Autism is a neurodevelopmental disorder characterized by impaired social interaction and communication, and by restricted and repetitive behavior. Autism begins in childhood. It is marked by the presence of markedly abnormal or impaired development in social interaction and communication and a markedly restricted repertoire of activity and interest. Manifestations of the disorder vary greatly depending on the developmental level and chronological age of the individual (DSM-IV).
- Broad-based gait · Frequent (79-30%)
- An abnormal gait pattern in which persons stand and walk with their feet spaced widely apart. This is often a component of cerebellar ataxia.
- Bulbous nose · Frequent (79-30%)
- Increased volume and globular shape of the anteroinferior aspect of the nose.
- Constipation · Frequent (79-30%)
- Infrequent or difficult evacuation of feces.
- Cryptorchidism · Frequent (79-30%)
- Testis in inguinal canal. That is, absence of one or both testes from the scrotum owing to failure of the testis or testes to descend through the inguinal canal to the scrotum.
- Gastroesophageal reflux · Frequent (79-30%)
- A condition in which the stomach contents leak backwards from the stomach into the esophagus through the lower esophageal sphincter.
Other findings in the same source
From: Orphanet
Additional reported features include Hypertelorism (Frequent (79-30%)); Hypotonia (Frequent (79-30%)); Intellectual disability, mild (Frequent (79-30%)); Intellectual disability, moderate (Frequent (79-30%)); Long philtrum (Frequent (79-30%)); Macrocephaly (Frequent (79-30%)); Nausea (Frequent (79-30%)); Overlapping toe (Frequent (79-30%)); Scoliosis (Frequent (79-30%)); Atrial septal defect (Occasional (29-5%)). This is a selected summary, not a complete description of the condition.
When it may begin
From: Orphanet
Infancy
Inheritance in the source
From: Orphanet
Autosomal recessive
Frequency and the population described
From: Orphanet
Reported case(s): 10.0; Worldwide. This is a published case count, not prevalence. Point prevalence: <1 / 1 000 000; Worldwide; Class only.
Understanding the inheritance label
From: MedlinePlus Genetics
An autosomal recessive pattern usually involves disease-causing changes in both copies of a gene. Parents may each carry one altered copy without having the condition themselves. A genetic counsellor can explain carrier testing and reproductive implications using the actual laboratory findings, rather than the condition name alone.
Which doctor should you see?
The suggested department for discussing Seizures-scoliosis-macrocephaly syndrome is Metabolic Medicine, with a metabolic specialist / clinical geneticist as the relevant type of clinician. Paediatrician (children) or physician (adults), with metabolic specialist / clinical geneticist referral.
This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.
How to prepare for an assessment
Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.
Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.
- Is a biochemical or molecular result needed to clarify the diagnosis?
- Does this condition require an individual plan for illness or reduced food intake?
- Should nutrition advice come from a specialist metabolic dietitian?
Treatment discussions and follow-up
The material gathered for this draft does not provide a complete condition-specific treatment pathway for Seizures-scoliosis-macrocephaly syndrome. That gap does not mean that treatment is unavailable. A clinician needs to establish the diagnosis and review current guidance before recommending medicines, procedures, rehabilitation or other support.
Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.
The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.
When to seek emergency help
Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.
This condition is usually assessed by a metabolic specialist / clinical geneticist. The Doctor Index does not list that speciality yet. A family physician or paediatrician can examine, arrange first tests and refer to the right specialist centre.
All metabolic medicine conditions →
Sources
- Orphanet — Seizures-scoliosis-macrocephaly syndrome — Orphadata Science, CC BY 4.0
- Human Phenotype Ontology Consortium — terminology definitions — HPO licence; definitions reproduced without alteration
- MedlinePlus Genetics — inheritance patterns — Public-domain Genetics education
- Government of India — Emergency Response Support System — Official reference for India emergency number
Source: MedlinePlus, National Library of Medicine. Orphadata Science: Free access data from Orphanet. © INSERM 1999; July 2026 data, CC BY 4.0. This product uses the Human Phenotype Ontology (hp/releases/2026-09-01). Only sources listed for this article apply. Source material has been selected and arranged; HPO definitions are reproduced without alteration. No source organisation endorses this compilation. Köhler S et al. The Human Phenotype Ontology project: linking molecular biology and disease through phenotype data. Nucleic Acids Research 2014;42(D1):D966–D974. doi:10.1093/nar/gkt1026.
General information, not advice about your situation. Errors can be reported through the corrections process. Reference TDI-C-2119.