X-linked lissencephaly with abnormal genitalia

What it is, symptoms and effects

From: MedlinePlus Genetics, National Library of Medicine

X-linked lissencephaly with abnormal genitalia (XLAG) is a condition that affects the development of the brain and genitalia. It occurs most often in males.

XLAG is characterized by abnormal brain development that results in the brain having a smooth appearance (lissencephaly) instead of its normal folds and grooves. Individuals without any folds in the brain (agyria) typically have more severe symptoms than people with reduced folds and grooves (pachygyria). Individuals with XLAG may also have a lack of development (agenesis) of the tissue connecting the left and right halves of the brain (corpus callosum).

In XLAG, the brain abnormalities can cause severe intellectual disability and developmental delay, abnormal muscle stiffness (spasticity), weak muscle tone (hypotonia), and feeding difficulties. Starting soon after birth, babies with XLAG have frequent and recurrent seizures (epilepsy). Most children with XLAG do not survive past early childhood.

Another key feature of XLAG in males is abnormal genitalia that can include an unusually small penis (micropenis), undescended testes (cryptorchidism), or external genitalia that do not look clearly male or clearly female.

Additional signs and symptoms of XLAG include chronic diarrhea, periods of increased blood glucose (transient hyperglycemia), and problems with body temperature regulation.

ORPHANET DEFINITION A rare genetic multiple congenital anomalies/dysmorphic syndrome characterized by lissencephaly, agenesis of the corpus callosum and other cerebral structural anomalies, early-onset intractable seizures, and ambiguous genitalia. Consequences of hypothalamic dysfunction, such as disturbed temperature regulation, may be observed. Additional anomalies including dysmorphic craniofacial features have been reported. The disease is fatal in infancy or childhood in males, while female carriers may be unaffected or show a milder phenotype with developmental delay, behavioral abnormalities, and seizures.

Inheritance

From: MedlinePlus Genetics, National Library of Medicine

X-linked dominant

Frequency in the source

From: MedlinePlus Genetics, National Library of Medicine

Reported family(ies): 30.0; Worldwide. This is a published case count, not prevalence. Point prevalence: Unknown; Worldwide; Class only.

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.

Agenesis of corpus callosum · Very frequent (99-80%)

Absence of the corpus callosum as a result of the failure of the corpus callosum to develop, which can be the result of a failure in any one of the multiple steps of callosal development including cellular proliferation and migration, axonal growth or glial patterning at the midline.

Ambiguous genitalia · Very frequent (99-80%)

A genital phenotype that is not clearly assignable to a single gender. Ambiguous genitalia can be evaluated using the Prader scale: Prader 0: Normal female external genitalia. Prader 1: Female external genitalia with clitoromegaly. Prader 2: Clitoromegaly with partial labial fusion forming a funnel-shaped urogenital sinus. Prader 3: Increased phallic enlargement. Complete labioscrotal fusion forming a urogenital sinus with a single opening. Prader 4: Complete scrotal fusion with urogenital opening at the base or on the shaft of the phallus. Prader 5: Normal male external genitalia. The diagnosis of ambiguous genitalia is made for Prader 1-4.

Cryptorchidism · Very frequent (99-80%)

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.

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.

Intellectual disability · Very frequent (99-80%)

The term intellectual disability or intellectual developmental disorder is used to describe significantly sub-average intellectual and adaptive functioning based on clinical assessment and as measured by individually administered, appropriately normed, standardized and validated tests of intellectual functioning and adaptive behavior, with onset during the developmental period from infancy through adolescence.

Microcephaly · Very frequent (99-80%)

Head circumference below 2 standard deviations below the mean for age and gender.

Pachygyria · Very frequent (99-80%)

Pachygyria is a malformation of cortical development with abnormally wide gyri with sulci 1,5-3 cm apart and abnormally thick cortex measuring more than 5 mm (radiological definition). See also neuropathological definitions for 2-, 3-, and 4-layered lissencephaly.

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.

Hypoplasia of penis · Very frequent (99-80%)

Death in infancy · Frequent (79-30%)

Death within the first 24 months of life.

Hypohidrosis · Frequent (79-30%)

Abnormally diminished capacity to sweat.

Hypotonia · Frequent (79-30%)

Hypotonia is an abnormally low muscle tone (the amount of tension or resistance to movement in a muscle). Even when relaxed, muscles have a continuous and passive partial contraction which provides some resistance to passive stretching. Hypotonia thus manifests as diminished resistance to passive stretching. Hypotonia is not the same as muscle weakness, although the two conditions can co-exist.

Malabsorption · Frequent (79-30%)

Impaired ability to absorb one or more nutrients from the intestine.

Ventriculomegaly · Frequent (79-30%)

An increase in size of the ventricular system of the brain.

Other findings in the same source

From: Orphanet

Additional reported features include Aganglionic megacolon (Occasional (29-5%)); Exocrine pancreatic insufficiency (Occasional (29-5%)); Micrognathia (Occasional (29-5%)); Patent ductus arteriosus (Occasional (29-5%)); Prominent forehead (Occasional (29-5%)); Spasticity (Occasional (29-5%)); Ventricular septal defect (Occasional (29-5%)). This is a selected summary, not a complete description of the condition.

When it may begin

From: MedlinePlus Genetics, National Library of Medicine

Neonatal

Inheritance in the source

From: MedlinePlus Genetics, National Library of Medicine

X-linked dominant

Frequency and the population described

From: MedlinePlus Genetics, National Library of Medicine

Reported family(ies): 30.0; Worldwide. This is a published case count, not prevalence. Point prevalence: Unknown; Worldwide; Class only.

Understanding the inheritance label

From: MedlinePlus Genetics

An X-linked dominant pattern involves a gene on the X chromosome. Expression can differ between individuals and between sexes. Family counselling requires the actual genetic finding and a clear family history; a general description cannot calculate the risk or severity for a particular child.

Which doctor should you see?

The suggested department for discussing X-linked lissencephaly with abnormal genitalia is Clinical Genetics, with a clinical geneticist as the relevant type of clinician. Paediatrician (children) or physician (adults), with clinical geneticist referral.

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

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 X-linked lissencephaly with abnormal genitalia. 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.