X-linked intellectual disability-cerebellar hypoplasia-spondylo-epiphyseal dysplasia syndrome

What it is

From: Orphanet

A rare genetic multiple congenital anomalies/dysmorphic syndrome characterized by global developmental delay, intellectual disability, growth retardation, hypotonia, cerebellar symptoms such as ataxia, spondyloepiphyseal dysplasia, and dysmorphic craniofacial features (including microcephaly, dolichocephaly, prominent ears, epicanthus, broad nasal bridge, long and flat philtrum, or small mouth). Additional reported manifestations are epilepsy, retinitis pigmentosa, and urogenital abnormalities, among others. Brain imaging may show cerebellar hypoplasia.

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.

Abnormal facial shape · Very frequent (99-80%)

An abnormal morphology (form) of the face or its components.

Intellectual disability, severe · Very frequent (99-80%)

Severe intellectual disability (ID) is defined as a type of ID characterized by severely sub-average adaptive functioning and intellectual functioning, with an intelligence quotient (IQ) the range of 20-34.

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.

Absent speech · Frequent (79-30%)

Complete lack of development of speech and language abilities.

Ataxia · Frequent (79-30%)

Ataxia refers to impaired coordination of voluntary muscle movement. Cerebellar ataxia refers to ataxia due to dysfunction of the cerebellum. This causes a variety of elementary neurological deficits including asynergy (lack of coordination between muscles, limbs and joints), dysmetria (lack of ability to judge distances that can lead to under- or overshoot in grasping movements), and dysdiadochokinesia (inability to perform rapid movements requiring antagonizing muscle groups to be switched on and off repeatedly).

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).

Cerebellar hypoplasia · Frequent (79-30%)

Cerebellar hypoplasia is a descriptive term implying a cerebellum with a reduced volume, but a normal shape and is stable over time.

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.

Delayed speech and language development · Frequent (79-30%)

A degree of language development that is significantly below the norm for a child of a specified age.

Floppy infant · Frequent (79-30%)

Floppiness/hypotonia is defined as reduced resistance to passive movement of joints. Physical examination of floppy/hypotonic infants shows head lag, lack of shoulder and elbow muscle contraction on traction response, inability to tighten the shoulder girdle muscles (or slipping through) when held under the axillae, scarf sign (when the arm is pulled to the opposite side, the arm wraps around the neck with the elbow crossing midline), hyperdorsiflexion of the feet, easy apposition of the thumb against the forearm, feet touching the cheek with ease and without discomfort, frog leg position, and inverted U sign on ventral suspension (head, arms, and legs hanging down without elbow or knee flexion and the trunk rounded in a dome shape).

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.

Growth delay · Frequent (79-30%)

A deficiency or slowing down of growth pre- and postnatally.

Macrotia · Frequent (79-30%)

Median longitudinal ear length greater than two standard deviations above the mean and median ear width greater than two standard deviations above the mean (objective); or, apparent increase in length and width of the pinna (subjective).

Mandibular prognathia · Frequent (79-30%)

Abnormal prominence of the chin related to increased length of the mandible.

Other findings in the same source

From: Orphanet

Additional reported features include Microcephaly (Frequent (79-30%)); Scoliosis (Frequent (79-30%)); Spondyloepiphyseal dysplasia (Frequent (79-30%)); Anteverted ears (Frequent (79-30%)); Atrial septal defect (Occasional (29-5%)); Bilateral tonic-clonic seizure (Occasional (29-5%)); Broad forehead (Occasional (29-5%)); Clinodactyly of the 5th finger (Occasional (29-5%)); Decreased testicular size (Occasional (29-5%)); Delayed puberty (Occasional (29-5%)). This is a selected summary, not a complete description of the condition.

When it may begin

From: Orphanet

Infancy; Neonatal

Inheritance in the source

From: Orphanet

X-linked recessive

Frequency and the population described

From: Orphanet

Reported case(s): 2.0; 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 X-linked recessive pattern involves a gene on the X chromosome. The number of X chromosomes and the particular genetic change influence how a condition is expressed. A genetic counsellor should interpret the result and the family history before discussing risks for relatives or future pregnancies.

Which doctor should you see?

The suggested department for discussing X-linked intellectual disability-cerebellar hypoplasia-spondylo-epiphyseal dysplasia syndrome is Orthopaedics, with a orthopaedic specialist as the relevant type of clinician. General physician / Family Medicine; paediatrician for children. Referral depends on symptoms.

Additional services that may be relevant, depending on the findings, include: Clinical Genetics.

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.

• What explains the change in pain, movement or function?
• Which activities need adjustment while the diagnosis is being clarified?
• What are the roles of rehabilitation, observation and surgery in this situation?

Treatment discussions and follow-up

The material gathered for this draft does not provide a complete condition-specific treatment pathway for X-linked intellectual disability-cerebellar hypoplasia-spondylo-epiphyseal dysplasia 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.