Global developmental delay-visual anomalies-progressive cerebellar atrophy-truncal hypotonia syndrome

What it is

From: Orphanet

Global developmental delay-visual anomalies-progressive cerebellar atrophy-truncal hypotonia syndrome is a rare, genetic, neurological disorder characterized by mild to severe developmental delay and speech impairment, truncal hypotonia, abnormalities of vision (including cortical visual impairment and abnormal visual-evoked potentials), progressive brain atrophy mainly affecting the cerebellum, and shortened or atrophic corpus callosum. Other clinical findings may include increased muscle tone in the extremities, dystonic posturing, hyporeflexia, scoliosis, postnatal microcephaly and variable facial dysmorphism (e.g. deep-set eyes, gingival hyperplasia, short philtrum and retrognathia).

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.

Corpus callosum atrophy · Very frequent (99-80%)

The presence of atrophy (wasting) of the corpus callosum.

Deeply set eye · Very frequent (99-80%)

An eye that is more deeply recessed into the plane of the face than is typical.

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.

Diffuse cerebellar atrophy · Very frequent (99-80%)

Diffuse unlocalised atrophy affecting the cerebellum.

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.

Retrognathia · Very frequent (99-80%)

An abnormality in which the mandible is mislocalised posteriorly.

Abnormality of visual evoked potentials · Frequent (79-30%)

An anomaly of visually evoked potentials (VEP), which are electrical potentials, initiated by brief visual stimuli, which are recorded from the scalp overlying the visual cortex.

Cerebral atrophy · Frequent (79-30%)

Atrophy (wasting, decrease in size of cells or tissue) affecting the cerebrum.

Dystonic gait · Frequent (79-30%)

Dystonic gait disorders frequently appear bizarre, particularly because activity increases dystonic tonus and posture. The abnormal posture of the foot in dystonic gait typically involves inversion, plantar flexion and tonic extension of the big toe. In many patients complex types of walking, such as walking backwards and running are paradoxically less impaired than walking forward and may seem completely unaffected. Sensory tricks, for instance, if the affected individual rests a hand on his or her neck, may improve or even normalize dystonic gait in some patients.

Gingival overgrowth · Frequent (79-30%)

Hyperplasia of the gingiva (that is, a thickening of the soft tissue overlying the alveolar ridge. The degree of thickening ranges from involvement of the interdental papillae alone to gingival overgrowth covering the entire tooth crown.

Hyporeflexia · Frequent (79-30%)

Reduction of neurologic reflexes such as the knee-jerk reaction.

Intellectual disability, profound · Frequent (79-30%)

Profound intellectual disability (ID) is defined as a type of ID characterized by profoundly sub-average adaptive functioning and intellectual functioning, with an intelligence quotient (IQ) below 20.

Progressive microcephaly · Frequent (79-30%)

Progressive microcephaly is diagnosed when the head circumference falls progressively behind age- and gender-dependent norms.

Other findings in the same source

From: Orphanet

Additional reported features include Prominent fingertip pads (Frequent (79-30%)); Scoliosis (Frequent (79-30%)); Short philtrum (Frequent (79-30%)); Limb hypertonia (Frequent (79-30%)); Abnormal pinna morphology (Occasional (29-5%)); Anal atresia (Occasional (29-5%)); Astigmatism (Occasional (29-5%)); Cerebral visual impairment (Occasional (29-5%)); EEG abnormality (Occasional (29-5%)); Esotropia (Occasional (29-5%)). This is a selected summary, not a complete description of the condition.

When it may begin

From: Orphanet

Childhood; Infancy

Inheritance in the source

From: Orphanet

Autosomal dominant; Autosomal recessive

Frequency and the population described

From: Orphanet

Reported case(s): 6.0; Worldwide. This is a published case count, not prevalence. Point prevalence: <1 / 1 000 000; Worldwide; Class only.

Which doctor should you see?

The suggested department for discussing Global developmental delay-visual anomalies-progressive cerebellar atrophy-truncal hypotonia syndrome is Clinical Genetics, with a clinical geneticist as the relevant type of clinician. Paediatrician (children) or physician (adults), with 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.

• Does the exact genetic or chromosome finding explain the observed features?
• Would a genetic counsellor help the family understand the result?
• Which organ-specific assessments are appropriate for this particular diagnosis?

Treatment discussions and follow-up

The material gathered for this draft does not provide a complete condition-specific treatment pathway for Global developmental delay-visual anomalies-progressive cerebellar atrophy-truncal hypotonia 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.